Diario de milewski

@frontyardscientist @graysquirrel @gregtasney @alan_dandie @prof_coffee @alzym @russellcumming

INTRODUCTION

In both Australia and southern Africa, the southwestern tips of the landmasses have rainfall mainly in winter (https://en.wikipedia.org/wiki/Mediterranean_climate). Adjacent to this mediterranean-type climate at temperate latitudes are semi-arid climates with rainfall mainly/partly in winter (https://en.wikipedia.org/wiki/Climate_of_Australia#/media/File:Australia_K%C3%B6ppen.svg and https://www.wits.ac.za/news/latest-news/opinion/2019/2019-02/scientists-split-on-south-africas-winter-and-summer-rainfall-zones.html).

In Australia, the relevant mediterranean regions occur disjunctly in Western Australia and South Australia. In southern Africa, the mediterranean region is restricted to Western Cape province, while the adjacent arid region extends to the westernmost part of Northern Cape province (https://en.wikipedia.org/wiki/Northern_Cape).

AIMS

In this Post, I make an intercontinental comparison of the sapindaceous indigenous floras of the two landmasses.

RESULTS: AUSTRALIA

Alectryon oleifolius https://www.inaturalist.org/taxa/783975-Alectryon-oleifolius and https://cdn.environment.sa.gov.au/landscape/docs/saal/alectryon-oleifolius-fact.pdf and https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Alectryon~oleifolius and https://bie.ala.org.au/species/https://id.biodiversity.org.au/node/apni/2900874

Diplopeltis huegelii https://www.inaturalist.org/taxa/1035979-Diplopeltis-huegelii
Diplopeltis intermedia https://www.inaturalist.org/taxa/1303004-Diplopeltis-intermedia
Diplopeltis petiolaris https://www.inaturalist.org/taxa/1412630-Diplopeltis-petiolaris

Dodonaea adenophora https://www.inaturalist.org/taxa/1353014-Dodonaea-adenophora
Dodonaea amblyophylla https://www.inaturalist.org/taxa/1442734-Dodonaea-amblyophylla
Dodonaea aptera https://www.inaturalist.org/taxa/1242403-Dodonaea-aptera
Dodonaea baueri https://www.inaturalist.org/taxa/928143-Dodonaea-baueri
Dodonaea bursariifolia https://www.inaturalist.org/taxa/1074467-Dodonaea-bursariifolia
Dodonaea caespitosa https://www.inaturalist.org/taxa/1417556-Dodonaea-caespitosa
Dodonaea ceratocarpa https://www.inaturalist.org/taxa/1004722-Dodonaea-ceratocarpa
Dodonaea concinna https://www.inaturalist.org/taxa/1442510-Dodonaea-concinna
Dodonaea ericoides https://www.inaturalist.org/taxa/1533196-Dodonaea-ericoides
Dodonaea hackettiana https://www.inaturalist.org/taxa/1162883-Dodonaea-hackettiana
Dodonaea hexandra https://www.inaturalist.org/taxa/962235-Dodonaea-hexandra
Dodonaea humifusa https://www.inaturalist.org/taxa/1442735-Dodonaea-humifusa
Dodonaea humilis https://www.inaturalist.org/taxa/958294-Dodonaea-humilis
Dodonaea inaequifolia https://www.inaturalist.org/taxa/958967-Dodonaea-inaequifolia
Dodonaea larreoides https://www.inaturalist.org/taxa/1413464-Dodonaea-larreoides
Dodonaea lobulata https://www.inaturalist.org/taxa/353810-Dodonaea-lobulata
Dodonaea microzyga https://www.inaturalist.org/taxa/940720-Dodonaea-microzyga
Dodonaea pinifolia https://www.inaturalist.org/taxa/1257565-Dodonaea-pinifolia
Dodonaea ptarmicifolia https://www.inaturalist.org/taxa/1363574-Dodonaea-ptarmicifolia
Dodonaea stenozyga https://www.inaturalist.org/taxa/499433-Dodonaea-stenozyga
Dodonaea viscosa https://www.inaturalist.org/taxa/122711-Dodonaea-viscosa

RESULTS: SOUTHERN AFRICA

Dodonaea viscosa 'angustifolia' https://www.inaturalist.org/taxa/122711-Dodonaea-viscosa

Erythrophysa alata https://www.inaturalist.org/taxa/183498-Erythrophysa-alata and https://pza.sanbi.org/erythrophysa-alata

Pappea capensis https://www.inaturalist.org/taxa/428559-Pappea-capensis and https://treesa.org/pappea-capensis/ and https://pza.sanbi.org/pappea-capensis

DISCUSSION

Alectryon/Pappea:

Alectryon (https://en.wikipedia.org/wiki/Alectryon_(plant)) and Pappea (https://www.inaturalist.org/posts/100103-a-comparison-of-sapindaceae-in-the-mediterranean-and-adjacent-arid-climates-of-australia-and-southern-africa#activity_comment_48b10771-dda9-4950-b8b3-291d52bbc76c) occur in the relevant semi-arid climates.

Both

• are large shrubs (multi-stemmed), unless reduced to tree-form (with a single bole) by large mammals (https://upload.wikimedia.org/wikipedia/commons/e/ea/Alectryon_oleifolius_plant.jpg and https://syzygium.xyz/saplants/Sapindaceae/Alectryon/Alectryon_oleifolius_ssp._canescens.html#&gid=1&pid=1), and
• are endozoochorous, with a reddish aril/arillode advertised to seed-dispersing birds by partial dehiscence of the capsule,

However, neither penetrates the mediterranean climate. This is partly owing to their dependence on fire-free regimes.

The Australian species, Alectryon oleifolius (https://keys.lucidcentral.org/keys/v3/scotia/key/Plants%20and%20Fungi%20of%20south%20western%20NSW/Media/Images/Alectryon_oleifolius_ssp._canescens/Alectryon_oleifolius_tree_501242_050910.jpg) differs from its approximate southern African counterpart, Pappea capensis, in

• being unspecialised in growth-form (https://upload.wikimedia.org/wikipedia/commons/e/ea/Alectryon_oleifolius_plant.jpg and https://syzygium.xyz/saplants/Sapindaceae/Alectryon/Alectryon_oleifolius_ssp._canescens.html#&gid=1&pid=1),
• having foliage that is particularly dull in hue, and similar in appearance to that of Dodonaea viscosa 'angustifolia',
• being cyanogenic in antiherbivore defence (https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0013/111190/prussic-acid-poisoning-in-livestock.pdf), and
• having relatively small fruits (https://www.gbif.org/species/7265069 and https://keys.lucidcentral.org/keys/v3/scotia/key/Plants%20and%20Fungi%20of%20south%20western%20NSW/Media/Images/Alectryon_oleifolius_ssp._canescens/Alectryon_oleifolius_Whyalla_CP_David_Poynter.jpg).

Please see

• https://www.inaturalist.org/posts/100103-a-comparison-of-sapindaceae-in-the-mediterranean-and-adjacent-arid-climates-of-australia-and-southern-africa#activity_comment_9a7aeac7-bbf5-4dc5-a36b-63de4ec10fb7, and
• https://www.inaturalist.org/posts/68618-the-puzzle-of-hakea-as-an-indigenous-woody-weed-in-currantbush-mixed-shrubland-in-western-australia.

Diplopeltis:

This relatively obscure genus seems typical of the Western Australian counterpart of coastal fynbos (https://www.jstor.org/stable/2260228) under semi-arid climates. It seems to be myrmecochorous (https://www.publish.csiro.au/BT/BT9750475), and is probably adapted to wildfire.

Dodonaea:

Dodonaea has undergone an evolutionary radiation in mediterranean and adjacent arid Australia, producing various shrubby growth-forms with evergreen foliage. These include

• myrmecochorous spp. (https://en.wikipedia.org/wiki/Myrmecochory), and
• at least one species with a 'burr' fruit, adhering to the pelage of rodents.

Dodonaea is indigenous also to mediterranean and adjacent arid southern Africa. This is extremely puzzling, biogeographically and in evolutionary terms.

Dodonaea viscosa has somehow found its way across the vast oceanic barrier, probably hundreds of thousands of years ago. It is a fully integrated species in a diverse Cape Flora (https://en.wikipedia.org/wiki/Cape_Floristic_Region) that is otherwise distinct from the corresponding flora in Australia.

This sharing of D. viscosa between the landmasses is neither a 'Gondwana link' (https://en.wikipedia.org/wiki/Gondwana) nor anthropogenic. Instead, it is an unique example of a tall shrub/low tree defying major biogeographical barriers.

Furthermore, the form of D. viscosa in southern Africa seems identical to one ('angustifolia') of the seven forms recorded in the species' original range in Australia as a whole.

This raises a paradox:
Dodonaea viscosa is intraspecifically variable in Australia. However, in southern Africa it has shown no subspeciation/ecotypy/raciality/genetic drift, despite being subject to several glacial/interglacial cycles in the Pleistocene.

One species that presents a somewhat parallel biogeographical puzzle is Metrosideros angustifolia (https://www.inaturalist.org/journal/milewski/81613-metrosideros-angustifolia-myrtaceae-the-pacific-face-of-fynbos#). This anomalous member of Myrtaceae resembles D. viscosa 'angustifolia' in growth- and foliage-form, and is sympatric with it. However, it differs ecologically, by being restricted to waterlogged substrates.

Erythrophysa:

Erythrophysa alata resembles D. viscosa - which is sympatric with it in Namaqualand in Northern Cape province - in being a drought-tolerant evergreen shrub with air-filled, somewhat winged, capsular fruits. However, it differs in the following ways:

• flowers (https://www.inaturalist.org/observations/243356855 and https://www.southernafricanplants.net/plantdata_sub.php?Mspec_ID=2365 and https://www.inaturalist.org/observations/227773842) suggesting pollination by a nectarivorous bird (https://www.inaturalist.org/taxa/145189-Cinnyris-fuscus) more specialised than any occurring in mediterranean and adjacent arid Australia,
• pinnate leaves (https://www.inaturalist.org/observations/237484643), similar to certain spp. of Dodonaea in Australia (https://www.inaturalist.org/observations/129530885), and
• a branching pattern (https://www.inaturalist.org/observations/233939691) suggesting nutrient-rich substrates, freedom from wildfire, and intense herbivory.

THE PUZZLE

Dodonaea viscosa (https://www.inaturalist.org/taxa/122711-Dodonaea-viscosa and https://prota.prota4u.org/protav8.asp?g=pe&p=Dodonaea+viscosa and https://www.anbg.gov.au/gnp/interns-2007/dodonaea-viscosa.html and https://anpsa.org.au/APOL27/sep02-1.html) is biologically puzzling in at least six ways.

Firstly, it is uniquely cosmopolitan for a woody plant. Long before human influence, it spread naturally across several oceans and then far inland on several continents.

Secondly, this wide natural distribution was achieved despite the fact that 60 other members of the same genus remain restricted to the same continent - and in many cases the same landscapes - from which D. viscosa originated.

Thirdly, its original occurrence was on a landmass, namely the 'island continent' of Australia/Sahul (https://en.wikipedia.org/wiki/Sahul), that has never been connected to any continent by a land-bridge.

Fourthly, its diaspores seem not to be particularly adapted for long-distance dispersal.

It is true that the seed-capsules have papery wings, suggesting anemochory (https://www.dictionary.com/browse/anemochory), and the seeds survive immersion in sea water (West, 1984, https://www.publish.csiro.au/sb/BRU9840001).

However,

• the capsules tend to remain attached to the plant for months (https://plantpono.org/pono-plants/dodonaea-viscosa-%CA%BBa%CA%BBali%CA%BBi/), as opposed to falling off and blowing away,
• the seeds possess a small elaiosome (clearly illustrated in https://spapps.environment.sa.gov.au/SeedsOfSA/speciesinformation.html?rid=1513#:~:text=Seed%20collecting%3A,for%201%20to%202%20weeks.), indicating local burial by ants, and
• most populations occur far from rivers or the coast, making it unlikely that the diaspore is particularly adapted for dispersal and sowing by means of flotation.

Fifthly, D. viscosa is polymorphic, in a way conforming to raciality rather than subspeciation or ecotypy (https://en.wikipedia.org/wiki/Ecotype).

Please see https://www.inaturalist.org/posts/99976-a-plant-that-seems-to-defy-biogeographical-and-evolutionary-rules-dodonaea-viscosa-sapindaceae#activity_comment_81def12b-fd99-44ea-9b4a-a264e1b52b8c.

In a given population, the leaves may take a distinctive form (e.g. https://wtlandcare.org/details/dodonaea-viscosa-subsp-cuneata/) without any geographical isolation from other forms.

By the same token, the leaves may remain true to form despite having been subjected to environmental pressures and 'genetic drift' on a completely different continent for hundreds of thousands of years.

Sixthly, D. viscosa has remarkably dense wood (air-dry specific gravity 1.2-1.25) for a fast-growing, 'weedy' (probably short-lived) tall shrub/short tree (up to 9 m high, https://landscapeplants.oregonstate.edu/plants/dodonaea-viscosa) that tends to act as a pioneer on bared ground.

DISCUSSION

The literature lacks any satisfactory hypothesis on how D. viscosa achieved its unique spread, either ecologically or mechanistically.

The following review of fruit-form and seed-dispersal in the family Sapindaceae, more generally, highlights the puzzle.

No sapindaceous plant seems to be adapted for long-distance dispersal.

This is because

• the typical fruit-form in this family is arillate (https://en.wikipedia.org/wiki/Aril), involving seed-dispersing animals ranging from ants through birds to mammals,
• those fruits adapted - by virtue of papery wings on the mature, dry capsule - to dispersal by wind tend not to move farther than a few hundred metres from the parent individual, and
• the seeds are not particularly small in any member of the Sapindaceae.

In Dodonaea, the aril is an outgrowth of the funicle (West, page 33). It is

• always so small that it is better-described as an elaiosome (https://en.wikipedia.org/wiki/Elaiosome) than as an aril, and
• absent in D. viscosa.

A relevant mystery is the adaptive value of the bright hues of the mature capsules of various spp. of Dodonaea, including D. viscosa (https://www.friendsgbg.org.au/uploads/images/Plants-in-Focus/Dodonaea%20viscosa.Lucy%20Pope.PiF.2018-11.1.150.PS.pdf and https://www.aboutgardendesign.com/plant-guide/item/dodonaea-viscosa-purpurea and https://resources.austplants.com.au/plant/dodonaea-boroniifolia/).

Please also see https://www.inaturalist.org/journal/milewski/100103-a-comparison-of-sapindaceae-in-the-mediterranean-and-adjacent-arid-climates-of-australia-and-southern-africa#.

...continued from https://www.inaturalist.org/journal/milewski/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae-part-1#

INTERCONTINENTAL SIMILARITY IN LACK OF LERP/MANNA/EXTRAFLORAL NECTAR IN DIETS

Meliphagids tend to eat honeydew/lerp/manna/extrafloral nectar as well as floral nectar (https://www.publish.csiro.au/mu/pdf/mu9800213#:~:text=Manna%2C%20honeydew%20and%20lerp%20have,of%20these%20resources%20and%20nectar. and https://www.tandfonline.com/doi/abs/10.1080/01584197.1980.11799277).

By contrast, nectariniids have not been recorded eating these alternative sugary exudates. The only exception of which I am aware is the ostensible eating of the sap of Elaeis guineensis (https://en.wikipedia.org/wiki/Elaeis_guineensis) by Cinnyris coccinigastrus (https://www.inaturalist.org/taxa/145182-Cinnyris-coccinigastrus), which may be anthropogenic.

I have not found any records of the eating of lerp/manna/extrafloral nectar in the meliphagids examined in this Post. This, as far as it goes, supports the notion of evolutionary convergence.

DISCUSSION

The above information shows a pattern of 'so near and yet so far'. There seems, at first sight, to be evolutionary convergence between certain meliphagids in Australia and certain nectariniids in southern Africa. However, closer scrutiny shows significant disparities in form and function.

There are two main ways of interpreting these disparities. Either the environments on the two landmasses are different enough that the adaptive outcomes (by means of natural selection) are also different, or convergence has been constrained by shortcomings in the ancestors.

In turn, the shortcomings were owing either to phylogenetic constraints or to geographical barriers to recruitment of suitable ancestors.

It is tempting to invoke the longstanding isolation of Australia, in explanation of the fact that a single family, viz. Meliphagidae, has undergone major adaptive radiation to a degree unrivalled by any avian family in southern Africa.

PHYLOGENETIC CONSTRAINTS?

The intercontinental differences pointed out here cannot be explained by means of phylogenetic constraints and the geographical isolation of Australia. This is because meliphagids show much adaptive versatility in relevant ways, including

• iridescence,
• form of the tongue, and
• form of the nest.

Iridescence is known in at least one species of meliphagid (https://en.wikipedia.org/wiki/T%C5%AB%C4%AB and https://www.inaturalist.org/taxa/12580-Prosthemadera-novaeseelandiae). Therefore, the failure of all the members of this family examined in this Post to develop iridescence is unlikely to be an accident of evolutionary history. It is instead likely to be adaptive in some poorly-understood way.

By a similar token, a brush-tipped, not tubular, tongue is known in at least one species of nectariniid (https://sora.unm.edu/sites/default/files/journals/condor/v073n04/p0485-p0486.pdf and https://www.inaturalist.org/taxa/979744-Kurochkinegramma-hypogrammicum).

One species of meliphagid (https://www.inaturalist.org/taxa/12364-Ramsayornis-modestus) does actually build a nest similar to that of nectariniids (https://www.perplexity.ai/search/does-the-brown-backed-honeyeat-Owk0Fg1ySme.S4UJwWfsEA). This is particularly significant because the other species in the same genus builds a cup-shaped nest, typical of meliphagids.

Again: the failure of all the members of this family examined in this Post to build dome nests is unlikely to be an accident of evolutionary history. It is instead likely to be adaptive, and the relative paucity of certain predators on the 'island continent' is a possible factor.

Also relevant to the question of phylogenetic constraints is the fact that nectariniids have in fact reached Australia. Indeed, several genera may have reached what is now the Australian mainland, when there was a broad land-bridge from what is now New Guinea. The failure of nectariniids to undergo evolutionary radiation across Australia indicates ecological unsuitability rather than an accident of history/phylogenetic constraints.

Further investigation is warranted of the possible difference between meliphagids and nectariniids in predation on relatively large and venomous spiders. My impression from the literature is that nectariniids are the family more resembling 'arachnophages', in the sense that they use their long beaks not only to probe flowers, but also to kill spiders safely (https://www.inaturalist.org/posts/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae#activity_comment_0590a394-7178-4d76-bec2-11bc68b0e569 and https://en.wikipedia.org/wiki/Black-bellied_sunbird).

AUSTRALIA

AVES

Parvipsitta porphyrocephala

https://www.inaturalist.org/taxa/1289564-Parvipsitta-porphyrocephala

Anthochaera carunculata woodwardi
35 cm 105 g
https://www.inaturalist.org/taxa/12622-Anthochaera-carunculata

Anthochaera lunulata

https://www.inaturalist.org/taxa/12621-Anthochaera-lunulata

Manorina flavigula

https://www.inaturalist.org/taxa/12223-Manorina-flavigula

Phylidonyris novaehollandiae longirostris
18 cm
https://www.inaturalist.org/taxa/12632-Phylidonyris-novaehollandiae

Phylidonyris niger gouldii

https://www.inaturalist.org/taxa/12638-Phylidonyris-niger

Gliciphila melanops melanops

https://www.inaturalist.org/taxa/144710-Gliciphila-melanops

Lichmera indistincta indistincta

https://www.inaturalist.org/taxa/12526-Lichmera-indistincta

Acanthorhynchus superciliosus

https://www.inaturalist.org/taxa/12237-Acanthorhynchus-superciliosus

Lichenostomus cratitius

https://www.inaturalist.org/taxa/12164-Lichenostomus-cratitius

Gavicalis virescens virescens

https://www.inaturalist.org/taxa/370319-Gavicalis-virescens

Melithreptus chloropsis

https://www.inaturalist.org/taxa/501225-Melithreptus-chloropsis

Zosterops lateralis chloronotus

MAMMALIA

Tarsipes rostratus

https://www.inaturalist.org/taxa/42788-Tarsipes-rostratus

Pseudomys albocinereus

https://en.wikipedia.org/wiki/Ash-grey_mouse

Pseudomys occidentalis

https://en.wikipedia.org/wiki/Western_mouse

Pseudomys shortridgei

https://en.wikipedia.org/wiki/Heath_mouse

SOUTHERN AFRICA

AVES

Promerops cafer
female 25-29 cm
'breeds during the winter months from March to August, but occasionally as early as February' (McLachlan and Liversidge 1980)
https://www.inaturalist.org/taxa/13442-Promerops-cafer

Anthobaphes violacea

https://www.inaturalist.org/taxa/145130-Anthobaphes-violacea

Cinnyris chalybeus chalybeus

https://www.inaturalist.org/taxa/145157-Cinnyris-chalybeus

Zosterops virens capensis

https://www.inaturalist.org/taxa/472770-Zosterops-virens

Ploceus capensis

https://www.inaturalist.org/taxa/13801-Ploceus-capensis

Ploceus velatus velatus

https://www.inaturalist.org/taxa/13804-Ploceus-velatus

Pycnonotus capensis

https://www.inaturalist.org/taxa/14594-Pycnonotus-capensis

MAMMALIA

https://pza.sanbi.org/sites/default/files/info_library/rodents.pdf
https://journals.co.za/doi/pdf/10.10520/AJA00423203_1071

Micaelamys namaquensis

https://www.inaturalist.org/taxa/851046-Micaelamys-namaquensis
https://www.sciencedirect.com/science/article/pii/S0254629909002361

Myomyscus verreauxii

https://www.inaturalist.org/taxa/74689-Myomyscus-verreauxii
https://www.inaturalist.org/taxa/589130-Leucospermum-prostratum

Acomys subspinosus

https://www.inaturalist.org/taxa/45587-Acomys-subspinosus

There are two permanent sea barriers between southeast Asia and first Wallacea (https://en.wikipedia.org/wiki/Wallacea) and then Australasia. The first is called the Wallace Line (https://en.wikipedia.org/wiki/Wallace_Line), and the second is called the Weber Line.

https://oceanexplorer.noaa.gov/okeanos/explorations/10index/background/biogeography/media/biogeography_lines.html

https://www.perplexity.ai/search/is-north-maluku-part-of-sahul-QsmsUpAKTkyh3O3NMuXHyA

https://en.m.wikipedia.org/wiki/Richard_Lydekker#/media/File%3AMap_of_Sunda_and_Sahul.svg

MELIPHAGIDAE (excluding Philemon and Melitograis) OF WALLACEA

https://www.inaturalist.org/taxa/12533-Lichmera-argentaurisWEST OF THE WEBER LINE

https://www.inaturalist.org/taxa/73083-Myzomela-chloroptera

https://www.inaturalist.org/taxa/73084-Myzomela-dammermani

https://www.inaturalist.org/taxa/1289511-Myzomela-prawiradilagae

https://www.inaturalist.org/taxa/12412-Myzomela-vulnerata

https://www.inaturalist.org/taxa/12453-Myzomela-blasii

https://www.inaturalist.org/taxa/786002-Myzomela-irianawidodoae

https://www.inaturalist.org/taxa/12312-Myza-celebensis

https://www.inaturalist.org/taxa/12535-Lichmera-lombokia

https://www.inaturalist.org/taxa/12536-Lichmera-monticola

https://www.inaturalist.org/taxa/12532-Lichmera-squamata

https://www.inaturalist.org/taxa/12537-Lichmera-deningeri

https://www.inaturalist.org/taxa/12534-Lichmera-notabilis

https://www.inaturalist.org/taxa/12538-Lichmera-flavicans

https://www.inaturalist.org/taxa/12315-Myza-sarasinorum

https://www.inaturalist.org/taxa/73085-Myzomela-wakoloensis

https://www.inaturalist.org/taxa/1263134-Myzomela-wahe

https://www.inaturalist.org/taxa/12416-Myzomela-boiei

https://www.inaturalist.org/taxa/1289522-Territornis-reticulata

MELIPHAGIDAE WEST OF THE WALLACE LINE

https://www.inaturalist.org/taxa/12526-Lichmera-indistincta

The following nectariniids occur in Wallacea:

• Anthreptes malaccensis (https://www.inaturalist.org/taxa/979598-Anthreptes-malacensis) extends to Sulawesi and the Lesser Sunda islands.
• Aethopyga siparaja (https://www.inaturalist.org/taxa/204458-Aethopyga-siparaja) extends to Sulawesi.
• Aethopyga duyvenbodei (https://www.inaturalist.org/taxa/13420-Aethopyga-duyvenbodei) occurs on Sangihe, an island located immediately north of Sulawesi.
• Cinnyris ornatus (https://www.inaturalist.org/taxa/1505007-Cinnyris-ornatus) extends to the Lesser Sunda islands (https://en.wikipedia.org/wiki/Lesser_Sunda_Islands).
• Cinnyris infrenatus (https://www.inaturalist.org/taxa/1505008-Cinnyris-infrenatus) occurs in southeasternmost Sulawesi (https://en.wikipedia.org/wiki/Wakatobi_Regency).
• Cinnyris teysmanni (https://www.inaturalist.org/taxa/1505012-Cinnyris-teysmanni) occurs on Kalaotoa Island.
• Aethopyga duyvenbodei (https://www.inaturalist.org/taxa/13420-Aethopyga-duyvenbodei) occurs in northeasternmost Sulawesi.
• Cinnyris buettikoferi (https://www.inaturalist.org/taxa/145195-Cinnyris-buettikoferi) occurs on Sumba Island.
• Cinnyris solaris (https://www.inaturalist.org/taxa/145196-Cinnyris-solaris) occurs on the Lesser Sunda islands and Timor island.

The following nectariniids occur in Australasia (https://en.wikipedia.org/wiki/Australasia):

• Cinnyris clementei (https://www.inaturalist.org/taxa/1505011-Cinnyris-clementiae) occurs in Maluku.
• Leptocoma aspasia (https://www.inaturalist.org/taxa/979764-Leptocoma-aspasia) of New Guinea is generalised in diet - with invertebrates and fleshy fruit-pulp apparently being equally important - than its congeners and most other nectariniids.
• Cinnyris fuscatus (https://www.inaturalist.org/taxa/1504995-Cinnyris-frenatus) occurs from Sulawesi through New Guinea (but not the island chain of the Lesser Sundas/Sumba/Timor) to northeastern Australia.

@kokhuitan @lukedowney @tonyrebelo @jeremygilmore @ludwig_muller @ptexis @vynbos @baldcoot @craigpeter @rion_c @rjq @moxcalvitiumtorgos @johnnybirder @jakob @christiaan_viljoen @shanafelt_ben @botswanabugs @thebeachcomber @wynand_uys @simontonge @bwjone432155 @jadonald @ratite @gumnut @gposs @skipperdogman @nyoni-pete @william-harland @lloyd_esler @bioshots_jm @chuditch @graham_winterflood @judebirder @em_nature @justinponder2505

INTRODUCTION

Australia and southern Africa are ecologically comparable.

Both landmasses possess a range of climates, from mediterranean (https://en.wikipedia.org/wiki/Mediterranean_climate) and adjacent arid to summer-rainfall tropical (https://en.wikipedia.org/wiki/Climate_of_Australia#:~:text=The%20largest%20part%20of%20Australia,varying%20between%20grasslands%20and%20desert. and https://en.wikipedia.org/wiki/Climate_of_South_Africa).

Furthermore, in both cases the substrates tend to be nutrient-poor, owing to profound weathering on a largely flat topography (https://pubmed.ncbi.nlm.nih.gov/17624961/ and https://www.researchgate.net/publication/6213166_Ecology_of_Australia_The_effects_of_nutrient-poor_soils_and_intense_fires and https://www.jstor.org/stable/2845371).

In both Australia and southern Africa, there are many and various plants pollinated mainly by birds (https://www.tandfonline.com/doi/pdf/10.1080/0028825X.1979.10432566#:~:text=The%20genera%20most%20frequently%20visited,insects%20as%20well%20as%20birds. and https://www.tandfonline.com/doi/abs/10.1080/0028825X.1979.10432566 and https://mdahlem.net/birds/plant/pollen.php and https://science.uct.ac.za/fitzpatrick/research-understanding-biodiversity-evolutionary-and-behavioural-ecology/bird-pollination-cape-floristic-region and https://naturesvalleytrust.co.za/wp-content/uploads/2023/07/Whitehead-K.-2018.pdf and https://www.sciencedirect.com/science/article/abs/pii/S0367253006000259 and https://www.jstor.org/stable/43234070).

On both landmasses, the flowers/inflorescences in question tend to be bright-hued, bearing copious nectar deep within a structure that makes it adaptive for nectarivorous passerine birds to have long, curved beaks.

In general, the norm in meliphagids is relatively large-bodied and short-beaked, whereas the norm in nectariniids is small-bodied and long-beaked. However, the variation seems sufficient for close counterparts potentially to have evolved on the two separate landmasses.

AIMS

It is widely believed that certain Meliphagidae (https://en.wikipedia.org/wiki/Honeyeater) in Australia and certain Nectariniidae (https://en.wikipedia.org/wiki/Sunbird) in southern Africa show evolutionary convergence (https://en.wikipedia.org/wiki/Convergent_evolution), as part of an adaptive syndrome of mutualism with ornithophilous plants (https://en.wikipedia.org/wiki/Ornithophily).

The aim of this Post is to test evolutionary convergence in the case of meliphagids in Australia vs nectariniids in southern Africa.

NON-CONVERGENCES EMERGING FROM MY INTERCONTINENTAL COMPARISON OF MELIPHAGIDS WITH NECTARINIIDS

The following scrutiny undermines the 'textbook' interpretation.

Meliphagids have undergone an extreme evolutionary radiation on the 'island continent', Australia. However, it is the differences between meliphagids and nectariniids that I find to be more significant than the similarities.

This failure of evolutionary convergence is partly in line with the observation that meliphagids generally differ from nectariniids in having relatively large bodies and relatively short beaks. However, the biological disparities are manifold, and most remain even in the closest intercontinental counterparts.

The main intercontinental disparities are as follows.

Firstly, no meliphagid in Australia has a beak as proportionately long as that of certain nectariniids in southern Africa.

In three genera (Nectarinia, Chalcomitra, and Cinnyris) in southern Africa, the length of the beak is at least 18% of the total length of the body (including the beak) in certain spp.

This is illustrated for Cinnyris afer in https://www.youtube.com/watch?app=desktop&v=d7Gg2wa9AJw.

The genus of meliphagids with the proportionately longest beak in Australia is Acanthorhynchus, for which I have found no measurements of beak length. However, this is less than 15% of body length, based on photos.

The meliphagid with the longest beak occurs beyond Australia, in New Guinea (https://en.wikipedia.org/wiki/Long-billed_honeyeater and https://ebird.org/species/lobhon2 and https://www.inaturalist.org/taxa/12359-Melilestes-megarhynchus). Even in this case, the beak seems not to rival that in the most extreme nectariniids in slenderness and proportional length.

Secondly, the tongues are remarkably different.

In meliphagids, the tongue is fairly simple except for its brush-like tip (https://www.perplexity.ai/search/does-the-morphology-of-the-ton-dWPr2lh8Qi.prkVX4Uv7Jg and https://www.perplexity.ai/search/can-the-tongue-of-any-nectarin-M7OaIr9IR86NcZp.ZVFZjA).

By contrast, in nectariniids the tongue is odd even among nectarivorous birds (https://www.biorxiv.org/content/10.1101/2024.05.14.594085v1.full.pdf). This is because it operates by means of suction, as opposed to either capillarity, or pressure exerted by the closure of the beak.

In other words, the tongue of nectariniids serves as a drinking straw (https://en.wikipedia.org/wiki/Drinking_straw), the main complication being the distal bifurcation of the straw.

Thirdly, the nostrils are not covered (operculate) in all meliphagids (https://avis.indianbiodiversity.org/books/meliphagidae/40335), whereas they are typically covered in nectariniids (https://biodiversity.org.au/afd/taxa/Nectariniidae and scroll to photo of Nectarinia famosa in https://www.sciencenews.org/article/sunbirds-feathers-iridescence-heat-light).

Fourthly, plumage and colouration differ according to the following syndrome. Meliphagids

• tend to be less sexually dimorphic than nectariniids;
• lack masculine breeding plumage in a seasonal context (https://www.perplexity.ai/search/in-nectariniidae-do-adult-male-rxXZ85P0T62TD9WeS6wEgA);
• (except for one species in New Zealand) lack iridescence in their plumage; by contrast, most nectariniids possess iridescent feathers, at least in males;
• never possess eclipse plumage (https://thebdi.org/glossary/eclipse-plumage/), which is common in nectariniids; and
• lack the pectoral tufts (which are conspicuously bright-hued) possessed by many nectariniids (https://www.perplexity.ai/search/does-any-meliphagid-possess-pe-xLw1BDwASGGbtUQe5_JhhA).

Fifthly, meliphagids typically build nests of cup-shape, whereas nectariniids typically build dome nests, protected and hidden by a roof (https://www.inaturalist.org/journal/milewski/98768-the-incidence-of-dome-nests-in-avifaunas-a-comparison-of-australia-and-southern-africa-under-similar-mediterranean-and-adjacent-arid-climates#).

Sixthly, the smallest-bodied meliphagids exceed the smallest-bodied nectariniids in body mass. This applies within Australia and southern Africa, where the minima are reached, respectively, by Myzomela sanguinolenta (females 8 g) and Cinnyris neergardi (females 6 g, https://www.inaturalist.org/posts/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae#activity_comment_65e44197-f882-4a14-909c-03d7b2635e5d).

CLOSEST INTERCONTINENTAL COUNTERPARTS

(My values for body length and body mass refer to adult females.)

In all the following cases:

• the tongue of meliphagids is brush-like, whereas that of nectariniids is tubular,
• the nest of meliphagids is open at the top, whereas that of nectariniids is sealed above, and
• there are no records of the consumption of sugary exudates other than floral nectar.

The meliphagid Sugomel nigrum (https://www.inaturalist.org/taxa/367631-Sugomel-nigrum, body length 11 cm, body mass 9.5 g) is fairly closely matched with the nectariniid Cinnyris fuscus (https://www.inaturalist.org/taxa/145189-Cinnyris-fuscus and https://thebdi.org/2024/06/04/dusky-sunbird-cinnyris-fuscus/, body length 10 cm, body mass ?8 g).

The habitat in both cases is the semi-arid interior of the landmass, where vegetation (including acacias in both cases) is sparse,

In both of these approximate counterparts,

• the plumage of males achieves conspicuousness by means of darkness, not hue or iridescence,
• the colouration differs between the sexes, and
• the populations tend to be nomadic.

The similarity in colouration is greatest when males of the nectariniid are in non-breeding plumage (https://www.inaturalist.org/posts/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae#activity_comment_68c95b95-0846-4b9d-85ab-c2631edd7749).

However, the following differences remain:

• the meliphagid remains larger-bodied than the nectariniid, with a proportionately smaller head and shorter beak,
• the meliphagid qualifies, in males, as pied/piebald (https://www.merriam-webster.com/dictionary/piebald), which is not quite emulated by C. fuscus (https://www.inaturalist.org/observations/229807463), let alone any other nectariniid,
• the meliphagid has frequently been recorded eating ash (https://www.researchgate.net/publication/289010983_Some_notes_on_the_Black_Honeyeater_Sugomel_niger_in_Western_Australia_with_special_reference_to_feeding_on_ash), which as far as I know has never been recorded in any nectariniid,
• the nectariniid remains categorically more iridescent (https://www.inaturalist.org/observations/47327328 and https://www.inaturalist.org/observations/152404812 and https://www.inaturalist.org/observations/122277798 and https://www.inaturalist.org/observations/103055723 and https://www.inaturalist.org/observations/74663407 and https://www.inaturalist.org/observations/47327356 and https://www.inaturalist.org/observations/27908216 and https://www.inaturalist.org/observations/156621773) than any meliphagid in Australia, and
• males of the nectariniid - even in non-breeding plumage - retain bright-hued pectoral tufts (https://www.inaturalist.org/observations/17509372 and https://www.inaturalist.org/observations/16648040 and https://www.inaturalist.org/observations/6591102), absent from meliphagids.

Sugomel nigrum is associated mainly with Myoporaceae (https://www.inaturalist.org/observations?subview=map&taxon_id=136365&view=species). The nectariniid is instead associated mainly with Asphodelaceae (https://www.inaturalist.org/observations?place_id=113055&subview=map&taxon_id=71400&view=species and https://www.naturepl.com/stock-photo-dusky-sunbird-cinnyris-fuscus-feeding-on-the-nectar-of-quiver-tree-nature-image01596050.html and https://www.inaturalist.org/observations/224213747 and https://www.inaturalist.org/observations/55666885).

The meliphagid Acanthorhynchus superciliosus (https://www.inaturalist.org/taxa/12237-Acanthorhynchus-superciliosus, female length 14 cm, body mass 9 g) is somewhat similar to the nectariniid Anthobaphes violacea (https://www.inaturalist.org/taxa/145130-Anthobaphes-violacea and http://stellenboschwriters.com/Stellenbirds/sun1.html, female length 12 cm, body mass 9.5 g, https://sora.unm.edu/sites/default/files/journals/condor/v095n01/p0115-p0126.pdf).

In both cases,

• colouration differs between the sexes,
• the beak is proportionately long, and
• there is a particular coevolutionary (mutualistic) association with extremely diverse floras (e.g. Proteaceae) in sclerophyllous, fire-prone vegetation (https://en.wikipedia.org/wiki/Kwongan and https://heartlandjourneys.com.au/about-us/ancient-wonderland/kwongan/ and https://en.wikipedia.org/wiki/Fynbos) on nutrient-poor, sandy substrates under mediterranean climates.

However, differences remain in

• the length of the beak (https://www.inaturalist.org/posts/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae#activity_comment_90cc4622-bbd7-4503-ab74-f7891d54c419),
• modes of flight (https://www.inaturalist.org/posts/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae-part-1#activity_comment_ca002a0e-38ee-4314-824e-6b1af5d7a273),
• colouration, with conspicuously pale-tipped tail (in flight) only in the Australian species, and iridescence only in the southern African species,
• clutch-size, which is normally two in the relevant meliphagids and nectariniids alike, but is often only one in A. superciliosus,
• egg size, which is 18 X 13 mm in the meliphagid, vs 16.5 X 12.4 mm in the nectariniid, and
• breeding season (https://www.inaturalist.org/posts/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae#activity_comment_12c18a8d-90b2-4d37-9f98-ad42baca9ec5).

Myzomela sanguinolenta (https://www.inaturalist.org/taxa/12443-Myzomela-sanguinolenta, body length 10 cm, body mass 8 g) is fairly similar to Hedydipna collaris (https://www.inaturalist.org/taxa/145122-Hedydipna-collaris and https://dewetswild.com/tag/anthreptes-collaris/#:~:text=Collared%20Sunbirds%20breed%20mainly%20during,hives%20of%20bees%20or%20wasps. and https://www.biodiversityexplorer.info/birds/nectariniidae/hedydipna_collaris.htm, body length 9.5 cm, body mass 8 g).

The meliphagid actually exceeds the nectariniid in sexual dimorphism in colouration.

Furthermore, both spp.

• are equally small-bodied, with M. sanguinolenta being the smallest-bodied and brightest-hued (in the case of males, which qualify as glossy albeit not iridescent) of all meliphagids (other than Ephthianura),
• have short beaks,
• are insectivorous as much as nectarivorous,
• depend on dense forests, and
• reach nearly to the southern extreme of the mainland, where rain falls year-round.

However,

• females of the meliphagid (https://www.graemechapman.com.au/library/viewphotos.php?c=268&pg=2) are duller-hued than those of the nectariniid (which are yellow and green, https://ebird.org/species/colsun2/TZ#:~:text=The%20male%20has%20a%20green,hover%20to%20catch%20insect%20prey.),
• not only does iridescence remain in the nectariniid, but it occurs in both females (https://www.inaturalist.org/observations/242214266) and males (https://www.inaturalist.org/observations/229059268 and https://www.inaturalist.org/observations/232094757 and https://www.inaturalist.org/observations/160806904),
• the meliphagid, unlike the nectariniid, is nomadic and associated mainly with flowering Myrtaceae,
• the meliphagid forages conspicuously, whereas the nectariniid forages unobtrusively, and
• the size of the clutch may differ, with only the nectariniid likely to lay as many as three eggs per breeding-attempt.

The intercontinental difference in the nests - in size as well as shape - is illustrated in:

• M. sanguinolenta https://www.birdsinbackyards.net/species/Myzomela-sanguinolenta, vs
• H. collaris https://upload.wikimedia.org/wikipedia/commons/9/94/Collared_Sunbird_%28Hedydipna_collaris%29_female_on_nest_..._%2830429792623%29.jpg.

The meliphagid Myzomela obscura (https://www.inaturalist.org/taxa/12376-Myzomela-obscura and https://search.informit.org/doi/abs/10.3316/informit.658559031573707, body length 13 cm, body mass ? g) is a counterpart for the nectarinid Cyanomitra olivacea (https://www.inaturalist.org/taxa/145136-Cyanomitra-olivacea, body length 13 cm, body mass 9 g).

Both forms

• lack sexual dimorphism in colouration,
• lack iridescence, even in males while breeding, and
• are remarkably dull-hued.

Myzomela obscura and C. olivacea are similar. They occur in wildfire-free, dense forests on the northeastern coastal strips of the landmasses.

However,

• the beak of the meliphagid (https://www.inaturalist.org/observations/191065425 and https://www.inaturalist.org/observations/217817820 and https://www.inaturalist.org/observations/215657135 and https://www.inaturalist.org/observations/199062178 and https://www.inaturalist.org/observations/101925662) is shorter than that of the nectariniid (https://www.inaturalist.org/observations/107888671 and https://www.inaturalist.org/observations/65335377 and https://www.inaturalist.org/observations/223149125),
• the diet of the meliphagid is more generalised than that of the nectariniid,
• the tongue of the meliphagid is particularly different from that of the nectariniid, because its tip has a particularly complex brush-like structure,
• the meliphagid lacks the bright-hued pectoral tufts retained by both sexes of the nectariniid (https://www.inaturalist.org/observations/7734503 and https://www.inaturalist.org/observations/91081303 and https://www.inaturalist.org/observations/226685593 and https://www.inaturalist.org/observations/193779256), and
• the nest of the nectariniid is even more different than usual from that of the meliphagid, because it has a 'tail', and the entrance is hooded.

Finally:
Cinnyris frenatus (https://www.inaturalist.org/taxa/1504995-Cinnyris-frenatus, body length 10 cm, body mass ?8 g) of tropical northeasternmost Australia is extremely similar to Cinnyris venustus (https://www.inaturalist.org/taxa/145188-Cinnyris-venustus, body length 10 cm, body mass 7 g) of northeasternmost southern Africa.

Both spp. are equatorial to tropical. The colouration is similar, including the sexual difference. (Is the Australian species the less sexually dimorphic in colouration?)

This, the closest intercontinental matching of all in the present context, does not represent much evolutionary convergence. This is because

• the intercontinental counterparts belong to a single, exceptionally widespread and speciose (total 63 spp.) genus, and
• the main convergence is in body size within the genus (relative to e.g. Cinnyris coccinigastrus, which may have double this body mass, based on body length of 14 cm).

to be continued in https://www.inaturalist.org/journal/milewski/99413-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae-part-2#...

https://www.inaturalist.org/journal/milewski/96927-is-the-common-hippopotamus-hippopotamus-amphibius-analogous-with-orangutans-pongo-spp-in-sexual-bimaturism-part-1#

https://www.inaturalist.org/journal/milewski/97918-is-the-common-hippopotamus-hippopotamus-amphibius-analogous-with-orangutans-pongo-spp-in-sexual-bimaturism-part-2#

https://www.inaturalist.org/journal/milewski/97780-sundry-notes-on-the-natural-history-of-the-common-hippopotamus-hippopotamus-amphibius-in-the-late-fifties-in-maputaland-by-kenneth-l-tinley#

https://www.inaturalist.org/journal/milewski/67690-floating-meadows-in-south-africa-with-particular-reference-to-behavioural-inversions-in-the-hippopotamus#

https://www.inaturalist.org/posts/82576-notes-on-hippopotamus-amphibius-from-haller-park-mombasa-kenya#

https://www.inaturalist.org/posts/82575-hippopotamidae-in-tropical-asia#

https://www.inaturalist.org/posts/85161-variation-in-walking-gaits-in-ungulates-part-1-why-some-hoofed-mammals-cross-walk-whereas-others-amble#

@tonyrebelo @jeremygilmore

INTRODUCTION

Dome nests (https://www.lls.nsw.gov.au/regions/murray/articles,-plans-and-publications/nrm-news-november-2020/birds-and-their-nests) are those combining the following characteristics:

• essentially spherical, as opposed to cup- or bowl-shaped,
• incorporating a roof, so that there is a restricted aperture for entrance/exit on the side of the structure,
• woven out of plant fibre (and spiderweb in some cases), as opposed to being made from mud, and
• located externally, as opposed to within cavities (hollows/holes in wood or the ground).

The concealment and enclosure of eggs and the incubating adult confer obvious adaptive advantages relative to predation.

Australia and southern Africa have similar climates and substrates, but differ greatly in their regimes of predation.

In general, the former landmass is relatively poor in predators, whereas the latter landmass is rich in predators. More particularly, Australia lacks counterparts for specialised predators at avian nests, such as

• the snake Dasypeltis (https://www.inaturalist.org/taxa/26717-Dasypeltis-scabra), and
• the raptor Polyboroides (https://www.inaturalist.org/taxa/5246-Polyboroides-typus).

AIMS

The main aim of this Post is to make an intercontinental comparison at the scale of avifaunal lists.

I base this approach on those regions with similar mediterranean-type and adjacent arid climates (https://en.wikipedia.org/wiki/Mediterranean_climate and https://link.springer.com/chapter/10.1007/978-3-642-65520-3_8#:~:text=The%20mediterranean%2Dtype%20climate%20of,the%20western%20half%20of%20Victoria. and https://www.tandfonline.com/doi/pdf/10.1080/01811789.1984.10826662).

I have excluded migratory birds that breed in the Northern Hemisphere, wintering in the Southern Hemisphere.

RESULTS

The following taxa of birds build dome nests in the relevant regions.

AUSTRALIA

Atrichornithidae:

Atrichornis clamosus https://www.inaturalist.org/taxa/7422-Atrichornis-clamosus

Estrildidae:

Stagonopleura all three spp. (https://en.wikipedia.org/wiki/Stagonopleura)

Acanthizidae:

Acanthiza apicalis https://www.inaturalist.org/taxa/72439-Acanthiza-apicalis
Acanthiza chrysorrhoa https://www.inaturalist.org/taxa/13469-Acanthiza-chrysorrhoa
Acanthiza inornata https://www.inaturalist.org/taxa/13466-Acanthiza-inornata
Acanthiza iredalei https://www.inaturalist.org/taxa/13472-Acanthiza-iredalei
Acanthiza lineata https://www.inaturalist.org/taxa/13467-Acanthiza-lineata
Acanthiza nana https://www.inaturalist.org/taxa/13470-Acanthiza-nana
Acanthiza pusilla https://www.inaturalist.org/taxa/13468-Acanthiza-pusilla
Acanthiza reguloides https://www.inaturalist.org/taxa/13471-Acanthiza-reguloides
Acanthiza robustirostris https://www.inaturalist.org/taxa/13475-Acanthiza-robustirostris
Acanthiza uropygialis https://www.inaturalist.org/taxa/13464-Acanthiza-uropygialis

Aphelocephala leucopsis https://www.inaturalist.org/taxa/13522-Aphelocephala-leucopsis

Calamanthus campestris https://www.inaturalist.org/taxa/979632-Calamanthus-campestris
Calamanthus fuliginosus https://www.inaturalist.org/taxa/13527-Calamanthus-fuliginosus
Calamanthus montanellus https://www.inaturalist.org/taxa/548191-Calamanthus-montanellus

Gerygone fusca https://www.inaturalist.org/taxa/13491-Gerygone-fusca
Gerygone olivacea https://www.inaturalist.org/taxa/13490-Gerygone-olivacea

Hylacola cauta https://www.inaturalist.org/taxa/72928-Hylacola-cauta
Hylacola pyrrhopygia https://www.inaturalist.org/taxa/72929-Hylacola-pyrrhopygia

Pyrrholaemus brunneus https://www.inaturalist.org/taxa/13477-Pyrrholaemus-brunneus

Sericornis maculatus https://www.inaturalist.org/taxa/1444429-Sericornis-maculatus

Smicrornis brevirostris https://www.inaturalist.org/taxa/13540-Smicrornis-brevirostris

Maluridae:

Amytornis textilis https://www.inaturalist.org/taxa/509110-Amytornis-textilis

Malurus assimilis https://www.inaturalist.org/taxa/827392-Malurus-assimilis
Malurus cyaneus https://www.inaturalist.org/taxa/12065-Malurus-cyaneus
Malurus elegans https://www.inaturalist.org/taxa/12063-Malurus-elegans
Malurus leucopterus https://www.inaturalist.org/taxa/12093-Malurus-leucopterus
Malurus pulcherrimus https://www.inaturalist.org/taxa/12072-Malurus-pulcherrimus
Malurus splendens https://www.inaturalist.org/taxa/12083-Malurus-splendens

Stipiturus malachurus https://www.inaturalist.org/taxa/12133-Stipiturus-malachurus
Stipiturus mallee https://www.inaturalist.org/taxa/12072-Malurus-pulcherrimus

Cisticolidae (https://en.wikipedia.org/wiki/Cisticolidae) :

Cisticola exilis (South Australia only) https://www.inaturalist.org/taxa/7657-Cisticola-exilis

Dicaeidae:

Dicaeum hirundinaceum https://www.inaturalist.org/taxa/13388-Dicaeum-hirundinaceum

Pomatostomidae:

Pomatostomus superciliosus https://www.inaturalist.org/taxa/14491-Pomatostomus-superciliosus

SOUTHERN AFRICA

Ploceidae:

Euplectes capensis https://www.inaturalist.org/taxa/13964-Euplectes-capensis
Euplectes orix https://www.inaturalist.org/taxa/13962-Euplectes-orix

Ploceus capensis https://www.inaturalist.org/taxa/13801-Ploceus-capensis
Ploceus velatus https://www.inaturalist.org/taxa/13804-Ploceus-velatus

Quelea quelea https://www.inaturalist.org/taxa/14005-Quelea-quelea

Estrildidae:

Coccopygia melanotis https://www.inaturalist.org/taxa/979663-Coccopygia-melanotis

Estrilda astrild https://www.inaturalist.org/taxa/13770-Estrilda-astrild

Ortygospiza atricollis https://www.inaturalist.org/taxa/204557-Ortygospiza-atricollis

Nectariniidae:

Anthobaphes violacea https://www.inaturalist.org/taxa/145130-Anthobaphes-violacea

Chalcomitra amethystina https://www.inaturalist.org/taxa/145142-Chalcomitra-amethystina

Cinnyris afer https://www.inaturalist.org/taxa/145163-Cinnyris-afer
Cinnyris chalybeus https://www.inaturalist.org/taxa/145157-Cinnyris-chalybeus
Cinnyris fuscus https://www.inaturalist.org/taxa/145189-Cinnyris-fuscus

Nectarinia famosa https://www.inaturalist.org/taxa/13300-Nectarinia-famosa

Cisticolidae:

Apalis thoracica https://www.inaturalist.org/taxa/7742-Apalis-thoracica

Cisticola fulvicapilla https://www.inaturalist.org/taxa/72731-Cisticola-fulvicapilla
Cisticola juncidis https://www.inaturalist.org/taxa/7697-Cisticola-juncidis
Cisticola subruficapilla https://www.inaturalist.org/taxa/72733-Cisticola-subruficapilla
Cisticola textrix https://www.inaturalist.org/taxa/7700-Cisticola-textrix
Cisticola tinniens https://www.inaturalist.org/taxa/7660-Cisticola-tinniens

Eremomela icteropygialis https://www.inaturalist.org/taxa/204508-Eremomela-icteropygialis
Eremomela gregalis https://www.inaturalist.org/taxa/15460-Eremomela-gregalis

Euryptila subcinnamomea https://www.inaturalist.org/taxa/7782-Euryptila-subcinnamomea

Malcorus pectoralis https://www.inaturalist.org/taxa/7703-Malcorus-pectoralis

Phragmacia substriata https://www.inaturalist.org/taxa/73280-Phragmacia-substriata

Prinia maculosa https://www.inaturalist.org/taxa/7730-Prinia-maculosa

Macrosphenidae:

Sylvietta rufescens https://www.inaturalist.org/taxa/15254-Sylvietta-rufescens

Paridae:

Melaniparus afer https://www.inaturalist.org/taxa/144845-Melaniparus-afer

Remizidae:

Anthoscopus minutus https://www.inaturalist.org/taxa/13671-Anthoscopus-minutus

DISCUSSION

On both continents, there is a major incidence of birds that build dome nests.

Most of the families differ, indicating that there has been evolutionary convergence in this aspect, in a broad sense.

However, several avifaunal elements are shared, viz.

• the families Estrildidae and Cisticolidae, and
• the genus Cisticola.

Meliphagidae does not feature in these lists, despite

• the extreme adaptive radiation of this family on the island continent, and
• the similarity of Acanthorhynchus, Lichmera, and Sugomel to certain nectariniids (https://www.inaturalist.org/journal/milewski/98889-failure-of-evolutionary-convergence-in-nectarivorous-birds-between-australia-meliphagidae-and-southern-africa-nectariniidae-part-1#).

I have no simple explanation for the broad equivalence of the two landmasses in the incidence of dome nests.

A next step would be a detailed comparison of the faunas of relevant predators in Australia and southern Africa.

However, the following intercontinental differences are noteworthy:

Among those small birds that have long beaks, adapted for nectarivory and the pollination of tubular flowers, dome nests occur in southern Africa (Nectariniidae) but not Australia.

By contrast, among wren-like birds that skulk in dense herbage/shrubbery, dome nests occur more in Australia (e.g. Maluridae and Atrichornithidae) than in southern Africa, e.g.

• Macrosphenidae (https://www.inaturalist.org/observations?place_id=6987&subview=map&taxon_id=144307&view=species) and
• Locustellidae (https://www.inaturalist.org/observations?place_id=6987&subview=map&taxon_id=200984&view=species).

INTRODUCTION

Lichmera indistincta is common in southwestern Australia, including the Perth Metropolitan area (https://en.wikipedia.org/wiki/Perth).

https://www.tandfonline.com/doi/abs/10.1080/03014223.1985.10428310 and https://library.sprep.org/content/introductory-ecological-biogeography-australo-pacific-meliphagidae

This species is easy to take for granted in Perth, being the local counterpart for the sunbirds (Nectariniidae) so common in gardens in Africa and Asia.

However, L. indistincta is odd in two ways, as follows.

Firstly, it is extremely dull-coloured, particularly in the male in breeding condition. By comparison, most morphologically similar, sunbird-like birds are 'flashy', with bright hues and/or iridescence (https://en.wikipedia.org/wiki/Mrs._Gould%27s_sunbird#/media/File:Mrs._Gould's-Sunbird_cropped.jpg and https://www.thoughtco.com/sunbird-facts-4767483 and https://africageographic.com/stories/sunbird-feathers-and-the-sweltering-cost-of-beauty/).

Secondly, it is the southernmost outlier of a genus that is otherwise restricted to tropical islands, north of the Australian continent.

Lichmera is most speciose at an equatorial latitude of about 4 degrees South. The northernmost reach of the genus is 2 degrees 40 seconds North, considerably beyond the equator. By contrast, L. indistincta reaches as far south as 35 degrees in Australia (https://www.inaturalist.org/observations/63368637) - which is farther south than the southernmost tip of Africa (https://latitude.to/articles-by-country/za/south-africa/8352/cape-agulhas).

How can these anomalies be explained?

BIIGEOGRAPHICAL PERSPECTIVE

Meliphagids (Meliphagidae, https://en.wikipedia.org/wiki/Honeyeater) are diverse and abundant in Australasia.

Most forms are somewhat specialised for the consumption of nectar. The most specialised forms have long beaks, suitable for probing flowers and inflorescences.

Some genera of meliphagids are associated with the temperate zone of Australia, whereas others are associated with the tropics.

Genera associated mainly with the temperate zone include

• Acanthorhynchus (https://www.inaturalist.org/observations?taxon_id=12236&view=species),
• Phylidonyris (https://www.inaturalist.org/observations?taxon_id=12630&view=species), and
• Melithreptus (https://www.inaturalist.org/observations?taxon_id=12245&view=species).

The following genera are ambivalent:

• Gliciphila (https://www.inaturalist.org/observations?taxon_id=144339&view=species),
• Gavicalis (https://www.inaturalist.org/taxa/370319-Gavicalis-virescens), and
• Meliphaga (https://www.inaturalist.org/observations?taxon_id=12263&view=species).

Genera associated mainly with the tropics include

• Lichmera (https://www.inaturalist.org/observations?taxon_id=12516&view=species), and
• Myzomela (https://www.inaturalist.org/observations?taxon_id=12366&view=species).

In my neighbourhood in the Perth metropolitan area (https://en.wikipedia.org/wiki/Perth), the Australian raven (Corvus coronoides, https://www.inaturalist.org/taxa/8040-Corvus-coronoides and https://www.graemechapman.com.au/library/viewphotos.php?c=420) is so common that I interact with it every day.

Recently, I encountered a particularly bold adult individual, presumably male (https://www.perplexity.ai/search/in-adults-of-corvus-coronoides-o5VBIG8MRtaJGtucfTFW6A). I took the opportunity to examine its eyes from close-up (a distance of less than one metre).

I noticed that

• the iris (https://en.wikipedia.org/wiki/Iris_(anatomy)) is white, contrasting sharply with the all-black plumage (https://www.flickr.com/photos/ozjulian/2327533593 and https://www.shutterstock.com/image-photo/australian-raven-portrait-64715767 and https://www.alamy.com/close-up-of-australian-raven-image555427782.html and https://www.youtube.com/watch?v=dVCGByUAnx8 and https://dl.id.au/1/g.php?c=1&i=794 and https://www.dreamstime.com/australian-raven-large-corvid-glossy-black-typical-caw-cawing-call-image158034917);
• the degree of dilation of the pupil seemed constant, in contrast to what I have previously observed in e.g. Ploceus (https://www.mpg.de/17701550/bird-pupils-behave-unexpectedly-different and https://www.parrotforums.com/threads/a-parrots-eyes-why-do-their-pupils-pin-and-dialate.102173/);
• there is a considerable degree of binocular vision (https://www.dreamstime.com/australian-raven-victoria-australia-loud-noisy-corvid-populates-countryside-victoria-image160962249 and https://www.gettyimages.com.au/detail/photo/portrait-of-an-australian-raven-in-the-grass-royalty-free-image/1406721638?phrase=australian+raven&searchscope=image%2Cfilm&adppopup=true and https://www.youtube.com/watch?app=desktop&v=2in0vObSWfM and https://stock.adobe.com/au/images/great-moustache-of-australian-raven/149734268?prev_url=detail and https://www.istockphoto.com/photo/black-raven-in-the-wild-gm1368520237-438484344?searchscope=image%2Cfilm and scroll in https://canberrabirds.org.au/birds/australian-raven/);
• the head is frequently and variously moved in various directions, in order to direct the gaze;
• there is obvious movement of the eyeballs within their sockets, as part of the shifts in gaze; and
• extremely rapid blinking occurs every several seconds, by means of the nictitating membrane (https://en.wikipedia.org/wiki/Nictitating_membrane).

My commentary is as follows:

It has been written that the eyes of birds tend to differ from those of primates (https://en.wikipedia.org/wiki/Primate) in being

• fixed in their sockets, and
• laterally, as opposed to frontally, placed on the head.

According to the above view, birds tend to move their heads, not their eyes, in aid of shifting their gaze.

However, my observations of the Australian raven have shown that this species - although it certainly does frequently move its head in shifting its gaze - actually resembles primates to a considerable degree. I refer particularly to

• movements of the eyeballs within the sockets, and
• binocular vision (https://en.wikipedia.org/wiki/Binocular_vision).

The following recalls what I observed: https://www.google.com.au/search?q=australian+raven+close-up+video&sca_esv=708ca891a389fdf3&sxsrf=ADLYWIKUe67CMaLLUO6NoPhFPf0QBVivrg%3A1726103610727&ei=OkDiZsH5K4X2seMP5eH4wAM&ved=0ahUKEwjB_r-EnbyIAxUFe2wGHeUwHjgQ4dUDCBA&uact=5&oq=australian+raven+close-up+video&gs_lp=Egxnd3Mtd2l6LXNlcnAiH2F1c3RyYWxpYW4gcmF2ZW4gY2xvc2UtdXAgdmlkZW8yBRAhGKABMgUQIRigAUiDIVCIB1j6FnABeAGQAQCYAaACoAHaC6oBAzItNrgBA8gBAPgBAZgCB6ACngzCAgoQABiwAxjWBBhHwgIHECEYoAEYCpgDAIgGAZAGCJIHBzEuMC41LjGgB58S&sclient=gws-wiz-serp#fpstate=ive&vld=cid:dd5219bc,vid:Oy-5zAtAmZE,st:0.

However, in this footage I see subtle, split-second fluctuations in the size of the pupil, which I did not notice in my own scrutiny of the specimen in question. This 'eye-pinning' is not nearly as obvious as in https://www.tiktok.com/@blueplanetpets/video/7057245366206565679?lang=en. However, it may deserve further investigation in genus Corvus.