Griffiths' Treatment of the Genera of Anthomyiidae in the Nearctic Region Part 1: Introduction

Note: Part 2 will be posted almost immediately after this. these are also my notes, not formal publication, even though this may end up on Google Scholar for some ridiculous reason.

The Anthomyiidae represent one of the most difficult to identify and neglected families of flies. First, recognizing the family itself from other families in Muscoidea can often be difficult. Generic diagnoses primarily describe differences in genitalia, which almost always requires dissection to see in calyptrate flies. References for keying fauna of the larger continents are highly lacking. When present, they are scattered, outdated in nomenclature, and/or perhaps importantly, can be highly inaccessible or expensive to obtain. No comprehensive classification exists for this family, with the few attempts not having substantial grounds in cladistic argumentation. The only molecular and evolutionary study of these flies had not been done since last year (Gomes at el., 2021). For a family that contains species of economic importance, specialized on by the considered founder of modern cladistics Dr. Willi Hennig, not as diverse as better known calyptrate families, and with species primarily inhabiting temperate or arctic regions, they should not be in the state they currently are in.
Dr. Graham C. D. Griffiths from the University of Alberta, to say the least, revised the species of the Nearctic Region in his multi-volume Flies of the Nearctic Region. Before the Anthomyiidae, his work consisted of extensive translations of the systematic works of Hennig, the higher-order systematics of flies, and especially on the taxonomy of Agromyzidae with Dr. Kenneth Spencer. His familiarity with several languages probably made him a great bridge between European and American workers in the systematics of these flies, which was certainly needed. He wrote in his Flies of the Nearctic Region that the species of Anthomyiidae even in the Palearctic were in extensive confusion due to inadequate descriptions and lack of study of the type specimens. This was until Hennig created his monograph of the family in 1967-1976. The state of the family in the Nearctic must have been worse. It still lagged behind the understanding of the Palearctic region at the time. Dr. Hugh Huckett was for 60 years the only taxonomist in North America for the family, and certainly the first and only specialist on them for the region at the time. While his work was actually an improvement over earlier literature, it still had several deficiencies. Many species could not be recognized from descriptions due to lack of information on the genitalia. Association of the sexes was also apparently problematic, so many of the allotypes were not the same species as the holotypes. Griffiths also wrote that Huckett proposed many synonyms for species already described from Europe. Griffiths hoped to further correct these inconsistencies, and he certainly did. Unfortunately, the entire work was not able to be completed as he was diagnosed with throat cancer in 2006 and died 3 years later. The relationships between the genera of Anthomyiidae (probably a key to genera), characterization of the family, a revision of the genus Botanophila, and brief comments on formal nomenclature were intended to be published according to his first volume.
Griffiths was also known for his strong opinions on morphology and phylogeny. He utilized sections and other ranks of aggregate species or groups between genera and species in the Anthomyiidae. Griffiths reasonably remarked that although he believes in these groups, they were not intended to necessarily be included in catalogues in spite of the worries some authors had about the concept of polynomial nomenclature. As for the ICZN, it does not recognize these ranks. They are all treated as names at the level of subgenera (except for the superspecies groups, which are not considered to be genus-group names). However, these names are not available regardless, because they are incorrectly in a binomial format rather than composed of only one word.
All in all, keys to the genera of Anthomyiidae in the Nearctic region are desperately needed and need to be accessible. The Manual of Nearctic Diptera includes a key to the genera of Anthomyiidae of the Nearctic region created by Dr. Hugh Huckett. Unfortunately, it was developed before the publication of Griffith's important monograph of the family, resulting in the key being highly outdated in terms of nomenclature and classification. The Global Biodiversity Information Facility, Systema Dipterorum, and perhaps other sites include many of these synonyms and their currently valid names which will be helpful in identifying these. The Manual's key includes the genus-group names Circia (=Alliopsis), Chelisia (=Anthomyia), Chiastocheta (the Nearctic species on the Manual are now in Botanophila), Pseudochirosia (=Alliopsis), Eremomyioides (=Eutrichota), Crinurina (=Lasiomma), Macrophorbia (=Lasiomma), Anthomyiella (=Calythea), Neohylemyia (=Leucophora), Proboscimyia (=Leucophora), Pycnoglossa (=Chirosia), Hylemyza (=Hylemya), Ganperdea (=Leucophora), Pegomya of couplet 35 (=Eutrichota), Nupedia (=Pegoplata), Pseudonupedia (=Paradelia), Paraprosalpia (=Alliopsis), Eremomyia (=Eutrichota), Craspedochoeta (=Anthomyia), Acrostilpna (=Lasiomma), Macateeia (=Botanophila), and Pegohylemyia (=Botanophila).
In anticipation of an attempt to reconstruct a more user-friendly key for the Nearctic genera of Anthomyiidae, generic synopses of the Anthomyiidae will first be compiled. I like to imagine the generic synopses proposed by Griffiths hinted at the direction of which he intended his own generic key to go as well. Although many workers think that keys to the genera in this family will unequivocally require genitalia in large part, I don't really think so. Before Griffith's final 2004 volume in his Flies of the Nearctic Region, however, that would have probably been true. Dr. Verner Michelsen did construct a key to the Neotropical genera in the Anthomyiidae chapter of the Manual of Central America published in 2010, and genitalia was not used at all in the couplets.
The higher-order classification of Anthomyiidae is shaky with very minimal proposals having been made, but better than the other calyptrate families. A summary of this matter has been provided by Gomes at al. (2021). Huckett's classification in the Manual of Nearctic Diptera is outdated and untenable. Michelsen (2000) proposed one of the best possible classifications for the family, dividing it into the subfamilies Myopininae, Pegomyinae, and Anthomyiinae, but excluded the genera Phaonantho and Coenosopsia from any subfamilies. I don't currently have access to Michelsen (2000). Gomes et al., (2021) shows that Phaonantho and Coenosopsia are not basal in the family, and formed a relationship with Hydrophoria and Zaphne (unproposed grouping). Another relationship between Calythea, Pegoplata, Enneastigma, and Myopina was recovered ("Myopininae?"). Another for Pegomya, Emmesomyia, Taeniomyia, and obviously Eutrichota ("Pegomyinae"?). Finally, the rest of Anthomyiidae or Anthomyiinae. Fucellia were not sampled, but Hennig suggested a clade consisting of Botanophila, Fucellia, and Chiastocheta. Gomes et al. (2021) also added "Hylemyza" to this relationship. A tribal classification is present in the informal Diptera of the British Isles, which was reviewed by Dr. Michael Ackland. It is remarkably close to what I have imagined would be a good classification, but some of those groups are not monophyletic (for example, Delia in Hydrophoriini). Based on their analyses, a classification could be proposed where Pegomyinae would include tribes Myopinini and Pegomyini (nonetheless, Myopininae could be monophyletic). A new subfamily Hydrophoriinae which could also include Hydrophoriini and Coenosopsiini. Anthomyiinae could be split into tribes Deliini and Anthomyiini. These are not formal proposals. Dolichopodidae: Hydrophorinae and Scathophagidae: Delininae may cause confusion. Additional genera also would be interesting to sample for these molecular studies, especially Parapegomyia and Hylemyia.

Glossary:
Anepimeron - the sclerite on the side of the thorax usually lacking strong setae, located immediately posterior to the anepisternum, above the katepisternum, essentially equivalent to our oblique muscles, same as pteropleuron, pteropleura, pteropleural
Anepisternum - probably the largest sclerite on the side of the thorax, there is a row of strong setae lining the posterior margin of this region, essentially equivalent to our oblique muscles in location
Apical - the tips of the body part, usually furthest away from the body (distal)
Antennae - the parts of the antennae are divided into three segments, the scape, pedicel, and flagellum. The scape is referred to as first antennal article in Griffiths. The pedicel second antennal article. The flagellum in calyptrates, referred to as third antennal article in Griffiths, is composed of a few units known as flagellomeres. These flies evolved to have the first flagellomere absurdly expanded into a bulb-like organ with many names, the first flagellomere, third antennomere, third antennal article, third antennal segment. The remaining flagellomeres became the arista.
Apomorphous - having derived or specialized value
Autapomorphous - being unique to a group, same as constitutive
Basal - (1) located closest to the body (2) an ancient or ancestral lineage; synonym: proximal
Calypters - the flap-like pieces of wing membrane located at the base of the wings, same as squama
Chaetotaxy - the physical characteristics including arrangement of setae on the body
Surfaces of chaetotaxy:
a - anterior
ad - anterodorsal
av - anteroventral
d - dorsal
p - posterior
pd - posterodorsal
pv - posteroventral
v - ventral
Discal - located on the disc or middle of a sclerite, such as discal scutellar seta
Distal - located furthest away from the body
Interfrontal - the middle black to reddish rectangular region on the forehead of the fly between the eyes, there is often a pair of interfrontal setae located shortly anterior to the ocellar setae
Face - the facial region of these flies is considered to be between the ptilinal fissures, usually covered by the antennae, and located between the vibrissa
Frons - the forehead of the fly between the eyes
Katepisternum, katepisternal - "hips" of the fly on the thorax that are over the middle pair of legs, it is located directly over them, there are usually 3-5 strong setae pointing in different directions on this region, same as sternopleura, sternopleuron, sternopleural
Lower crossvein - the vein on the wings that forms the end of a noticeable, sharply, nearly right-angled rectangular region, same as crossvein dm-cu
Marginal - located at the edge of a sclerite
Mentum - a sclerotized region on the proboscis, it excludes the membranous area closer to the chin and the spongy part at the end
Meron - the "hips" of the fly on the thorax that are over the hind pair of legs, located slightly below and in front of the base of the halteres, same as hypopleuron
Notopleura, notopleural, notopleuron, notopleural depression - a sclerite located at the end of the transverse suture on top of the thorax, there are usually only two equidistant pairs of widely separated setae on them, essentially equivalent to our serratus anterior muscles
Parafrontals - the silvery linear area on the head between the interfrontal area and the eyes of the fly. Griffiths considers these to be the same as the parafacials, which is what this region graduates into below the base of the antennae, lateral to the face.
Plesiomorphy - character state found in the ancestor of a group
Posthumerals - Setae between the humeri or the bulged area on the shoulders of the presutural region on the thorax and the presutural dorsocentral setae. The labeling of the presutural area of the thorax is convoluted among taxonomic works. The posthumeral system is much more intuitive than the "presutural anterior intra-alar" system that McAlpine and the Canada JAI Pollenia key uses (and O'Hara agrees). This is because the presutural setae are not neatly organized into rows of setar as well as the postsutural region. It is better to refer to the setae immediately around the postpronota/humeri using a different system than the intraalar/supraalar system. They are used here as a formula "Posthumeral [# of anterior posthumeral]+[# of posterior]" where "anterior posthumeral" are synonymous with inner posthumeral and anterior intra alar. "Posterior posthumeral" are synonymous with outer posthumeral and anterior supra alar.
Postsutural - a line or suture, sometimes incomplete, can be imagined across the thorax, dividing it into anterior and posterior portions. The posterior portion is referred to as postsutural.
Prealar - anterior postsutural supra-alar seta, often located just above posterior notopleural seta
Presutural - a line or suture, sometimes incomplete, can be imagined across the thorax, dividing it into anterior and posterior portions. The anterior portion is referred to as presutural.
Proepisternum - the major sclerite visible in side view on the very anterior portion of the thorax, they're like the collar bones in a human, same as propleural depression
Prosternum - A sclerite over the neck on the underside of the fly, located between two membranous areas between the two fore coxae
Pulvilli - the tarsal pads
Sclerite - a chitinized plate or region on the body, usually used to describe these parts of the thorax, and usually gray-colored
Scutellum - the shield-like sclerite noticeable on the back of the fly between the wings in top view
Subcosta - on the anteiror margin of the wing, it is the second most notable vein to reach the wing margin
Synapomorphy - a character shared by the ancestor of a taxon
Symplesiomorphy - character with the value ancestral for the family and shared by several groups, usually referred to as groundplan, but that word here may also refer to plesiomorphy
Tarsomeres, tarsal articles - the units the feet of the fly are divided into. They can be modified, expanded in size compared to the tarsomeres on the other legs or they may possess long setulae in the males of some species, rarely females
Vibrissae - the two strong setae pointing forward on the face of the fly not on the antennae

References:
Evenhuis, N.L. & Pape, T. (editors). 2022. Systema Dipterorum, Version 3.9. http://diptera.org/, accessed on 4 August 2022.
Gomes, L.R.P., Souza, D.S., Carvalho, C.J.B. de. 2021. First insights into the evolution of neotropical anthomyiid flies (Diptera: Anthomyiidae). Systematics and Biodiversity 19(7): 724-737.
Griffiths, G.C.D. 1983-2004. Anthomyiidae. Flies Nearctic Region 8(2): 1-160 (=no. 1), 1983; 161-288 (=no. 2), 1983; 289-408 (=no. 3), 1984; 409-600, (=no. 4), 1984; 601-728 (=no. 5), 1986; 729-952 (=no. 6), 1987; 953-1048 (=no. 7), 1991; 1049-1240 (=no. 8), 1991; 1241-1416 (=no. 9), 1992; 1417-1632 (=no. 10), 1993; 1633-1872 (=no. 11), 1996; 1873-2120 (=no. 12), 1998; 2121-2288 (=no. 13), 2001: 2289-2484 (=no. 14), 2003: 2485-2635 (=no. 15), 2004.
Holmberg, R.G. 2017. Entomological Society of Canada/La Société d’entomologie du Canada, https://esc-sec.ca/wp/wp-content/uploads/2017/02/Obit_Griffiths_Graham.pdf
Michelsen, V. 2000. Oldest authentic record of a fossil calyptrate fly (Diptera): a species of Anthomyiidae from early Coenozoic Baltic amber. Studia Dipterologica 7: 11–18.
Michelsen, V. 2010. ANTHOMYIIDAE (ANTHOMYIID FLIES). In: Brown, B.V., Borkent, A., Cumming, J.M., Wood, D.M., Woodley, N.E. & Zumbado, M.A. (Eds.), Manual of Central American Diptera. Vol. 2. NRC Research Press, Ottawa, pp. 1271-1276.

Publicado por aispinsects aispinsects, 09 de agosto de 2022

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