Costal vein chaetotaxy, a neglected character source in Fanniidae and Muscidae (Diptera: Calyptratae) Author Michelsen, Verner 9BD4846E-F4D0-4DB2-A567-FAF0A58B6D98 Natural History Museum of Denmark, University of Copenhagen, Denmark. vmichelsen@snm.ku.dk text European Journal of Taxonomy 2022 2022-06-28 826 94 134 http://dx.doi.org/10.5852/ejt.2022.826.1839 journal article 86210 10.5852/ejt.2022.826.1839 ed37ce13-a67c-4146-b99e-db8ede0a145b 2118-9773 6784127 34BA1AB7-6107-4636-9645-B1C0216DCE5E Subfamily Azeliinae Robineau-Desvoidy, 1830 A subfamily of ‘lower’ Muscidae including the former Achanthipterinae Hennig, 1962 ( Kutty et al. 2014 ). Species from nine of a total of 12 recognized genera were examined ( Table 1 ). • Achanthiptera Rondani, 1856 The only known species, Achanthiptera rohrelliformis (Robineau-Desvoidy, 1830) , has vein C extensively setulose ventrally and bare dorsally (state A4 ). • Potamia Robineau-Desvoidy, 1830 Both examined species, Potamia littoralis Robineau-Desvoidy, 1830 and P . setifemur (Stein, 1916) , have vein C extensively setulose ventrally and bare dorsally (state A4 ). • Australophyra Malloch, 1923 The only known species, Australophyra rostrata (Robineau-Desvoidy, 1830) , has the ventral costal setulae confined to CS1 (state A2) . • Azelia Robineau-Desvoidy, 1830 ( Fig. 5A–B ) A total of 10 species was examined. They all have vein C bare ventrally (state A0 ), as shown by Azelia cilipes (Haliday, 1838) ( Fig. 5A–B ). • Drymeia Meigen, 1826 ( Fig. 6A–C ) A large, morphologically varied genus found primarily in the northern and elevated parts of the Holarctic region. More than 10 examined species of Drymeia , including some unidentified ones, agree with Azelia in the absence of ventral costal setulae (state A0 ), as shown by D. vicana (Harris, 1780) ( Fig. 6A ). One species, D. hamata (Fallén, 1823) ( Fig. 6B–C ), differs by having vein C extensively setulose ventrally (state A4 ). Ventral setulae are also seen on CS 1 in Drymeia tetra (Meigen, 1826) and some D . alpicola (Rondani, 1871) , but these are setulae displaced from the lower anterior spinule-setula row. • Hydrotaea Robineau-Desvoidy, 1830 ( Fig. 7A–C ) Examination of a large number of species showed that vein C is bare dorsally and with a trend towards loss of ventral costal setulae. Two species, Hydrotaea cyrtoneurina (Zetterstedt, 1845) ( Fig. 7A ) and H . ringdahli Stein, 1916 , have vein C extensively setulose ventrally (state A4 ). The following species have ventral costal setulae confined to CS1 (state A2 ): Hydrotaea anxia (Zetterstedt, 1838) , H. cyaneiventris Macquart, 1851 , H. dentipes (Fabricius, 1805) ( Fig. 7B ), H. hirticeps (Fallén, 1824) , H. militaris (Meigen, 1826) , H. palaestrica (Meigen, 1826) and H. similis Meade, 1887 . Some species have ventral setulae on less than the basal half of CS1 (state A1 ): Hydrotaea capensis (Wiedemann, 1818) , H. chalcogaster (Wiedemann, 1824) , H. diabolus (Harris, 1780) and H. ignava (Harris, 1780) . Most species examined are without ventral setae on vein C (state A0 ): Hydrotaea aenescens (Wiedemann, 1830) , H. borussica Stein, 1899 , H. cinerea Robineau-Desvoidy, 1830 , H. floccosa Macquart, 1835 , H. irritans (Fallén, 1823) , H. glabricula (Fallén, 1825) , H. meridionalis Portschinsky, 1882 , H. meteorica (Linnaeus, 1758) ( Fig. 7C ), H. pandellei Stein, 1899 , H. pellucens Portschinsky, 1879 , H. penicillata (Rondani, 1866), H. pilipes Stein, 1903 , H. pilitibia Stein, 1916 , H. scambus (Zetterstedt, 1838) , H. tuberculata Rondani, 1866 and H. unispinosa Stein, 1898 . In Hydrotaea borussica , H. irritans and allied species, the lower anterior spinule-setula row on the basal part of CS1 consists of setulae only, some of which are frequently displaced ventrally. • Neohydrotaea Malloch, 1924 The only examined species, Neohydrotaea lundbecki (Michelsen, 1978) , has vein C bare dorsally and extensively setulose ventrally (state A4 ). • Thricops Rondani, 1856 Examination of a large number of species revealed that most of them have vein C bare dorsally and extensively setulose ventrally (state A4 ): Thricops aculeipes (Zetterstedt, 1838) , T. beckeri (Pokorny, 1893) , T. culminum (Pokorny, 1889) , T. cunctans (Meigen, 1826) , T. foveolatus (Zetterstedt, 1845) , T. furcatus (Stein, 1916) , T. genarum (Zetterstedt, 1838) , T. hirtulus (Zetterstedt, 1838) , T. innocuus (Zetterstedt, 1838) , T. longipes (Zetterstedt, 1845) , T. nigrifrons (Robineau-Desvoidy, 1830) , T. nigritellus (Zetterstedt, 1838) , T. rostratus (Meade, 1882) , T. semicinereus (Wiedemann, 1817) , T. separ (Zetterstedt, 1845) , T. septentrionalis (Stein, 1898) , T. simplex (Wiedemann, 1817) (males), T. spiniger (Stein, 1904) , T. sudeticus (Schnabl, 1888) , T. tomkovichi Vikhrev in Vikhrev & Sorokina, 2009 and T. vaderi Savage, 2003 . Fig. 5. Azelia cilipes (Haliday, 1838) ♀. A . Wing, ventral view. B . Detail of wing showing CS1‒3, ventral view. Fig. 6. ♀♀ of Drymeia Meigen, 1826 . A . D . vicana (Harris, 1780) , detail of wing showing CS1‒3, ventral view. B . D . hamata (Fallén, 1823) , wing, ventral view. C . Same, detail of wing showing CS1‒3, ventral view. Females of Thricops simplex tend to have a short, irregular row of dorsal costal setulae on CS2 and adjacent basal part of CS3 (state A6 ). A more extensive row of dorsal costal setulae on CS2 and CS3 (state A7 ) is seen in Thricops albibasalis (Zetterstedt, 1849) , T. lividiventris (Zetterstedt, 1845) and T. rufisquamus (Schnabl, 1915) (only female examined). In Thricops diaphanus (Wiedemann, 1817) , the dorsal costal setulae tend to occupy CS1‒3 (state A8 ), although bare patches distally on CS1 and on CS2 do occur in some males. • Huckettomyia Pont & Shinonaga, 1970 A small, exclusively northern Palaeartic genus. The single male of Huckettomyia watanabei Pont & Shinonaga, 1970 examined is extensively setulose on the dorsal side of vein C (state A8 ).