Amaurosoma longicorne (von Roser, 1840 ), 2008

Šifner, František, 2008, Three new species of the family Scathophagidae (Diptera) from the Palaearctic region with a redescription of the male of Amaurosoma longicorne, Acta Entomologica Musei Nationalis Pragae (suppl.) 48 (1), pp. 103-109 : 104-106

Amaurosoma longicorne (von Roser, 1840)

( Figs. 1-3 )

Cordylura longicornis von Roser, 1840: 59

Material examined. CZECH REPUBLIC: BOHEMIA mer., Malšice (6653), 4.v.1976, 1 ♁, Jan Máca leg., F. Šifner 1982 det. (coll. Šifner).

Redescription. Male. Body length 5 mm, primary colour black.

Head. Dark, orbits, parafacialia, frontal vitta and hind portion of head black, face, genae and narrow strip in front of frontal vittae yellow, three pairs of frontal setae, two pairs of orbital setae, scape, pedicel and entire antennae including bare arista black, aristomere 3 long, three times as long as basally wide, second aristomere only slightly prolonged. Palpi yellow with yellow hairs, vibrissal callus with one vibrissa, and genae in hind portion with yellow hairs.

Thorax. Acrostichal bristles sparse, three distinct katepisternal bristles, two scutellar bristles, other chaetotaxy standard, wings hyaline, all veins distinct, vein Cu 1 + 1A ends at wing margin. All legs yellow, meso- and metafemora slightly darkened dorsoapically, procoxae distinctly and conspicuously yellow.

Abdomen. Sternite 4 very short and wider than long, sternite 3 rectangular and proximally with an incision, lobes of sternite 5 long, straight, only apically slightly narrowed, basal inner portion of lobes distinctly enlarged and with short bristles at its medial edges ( Fig. 1 ). Surstyli slightly arched, with short and fine bristles on inner side, cerci short ( Fig. 2 ), praegonite straight and narrow, slightly broadened apically with one subapical bristle ( Fig. 3 ).

Female unknown.

Differential diagnosis. Amaurosoma longicorne differs from the nearest species, A. inerme Becker, 1894 , by the following characters: aristomere distinctly long, praegonite apically broadened with one subapical bristle, abdominal sternite 4 very short, and abdominal sternite 3 long with a proximal incision.

Distribution. Czech Republic (this paper), Germany (VON ROSER 1840).

Discussion. The type locality of this species is Germany, probably the environs of Württenberg (VON ROSER 1840). The holotype designation is unclear and its depository is unknown. The original Latin description of C. longicornis is very brief: ‘thorace cinereo, abdomine nigro, palpi albis; antennis longitudine capitis; pedibus flavis, posticis apice femorum et tibiarum fuscis’ [= thorax grey, abdomen black, palpi pale; antennae as long as head; legs yellow, tips of hind femora and tibiae darkened] (VON ROSER 1840). BECKER (1894) somewhat extended the original description, e.g. by stating: ‘femoribus anticis intus setis nullis’ [= fore femora without short bristles on its interior side], fronte prominente antice flava, antennis nigris longis angustis, vibrissa unica [= frons prominent and anteriorly yellow, antennae black, long and narrow, only one vibrissa]. An important fact mentioned in the German part of the redescription is: ‘...das zweite Borstenglied bei Männchen verlängert’ [= second article of arista in male prolonged…]. It is evident from Becker’s text that he had both sexes at hand (cf. BECKER 1894: 115).

I was able to examine the following four specimens, previously incorrectly identified as A. longicorne , from the Becker collection deposited in the Museum für Naturkunde, Berlin: Two females of Spathephilus breviventris (Loew, 1973) labelled ‘Panten [= Prochowice near Legnica, Poland], 16.5.[19]09 // Nanna longicornis v. Ros., det. 1962 J.R.Vockeroth // Zool. Mus. Berlin’. I attached a label: ‘ Spathephilus breviventris (Loew, 1973) , ♀, det. F.Šifner, 2007’.

One female of Amaurosoma brevifrons (Zetterstedt, 1838) labelled ‘Panten [= Prochowice near Legnica, Poland], 16.5.[19]09 // Nanna longicornis v. Ros., det. 1962 J.R.Vockeroth // Zool. Mus. Berlin’. I attached a label: ‘ Amaurosoma brevifrons (Zett., 1838) , ♀, det. F. Šifner, 2007’.

One male of Amaurosoma articulatum Becker, 1894 , labelled ‘Dohnan [= Dohňany (6875) in the Biele Karpaty Mts., Slovakia], 23.4.[?]30449 // Nanna longicornis v. Ros., det. 1962 J.R.Vockeroth,♁ // Zool.Mus. Berlin’. I attached a label: ‘ Amaurosoma articulatum Becker, 1894 , det. F. Šifner, 2007’. This specimen is atypically coloured: the basic colouration is brown and the bristles on the interior side of fore femora are very short and hardly distinct.

Only the male from Malšice ( Czech Republic) corresponds to the Becker’s redescription and differs from all species of the genus Amaurosoma by the following characters: first aristomere long, praegonite broadened apically, and the shape of abdominal sternites 3-5 including lobes. I regard this species as valid.

Figures

Figs. 1-6. 1-3: Amaurosoma longicorne (von Roser, 1840); 4-6: A. bernasconii sp. nov., male, holotype. 1, 4 – abdominal sternites 4 and 5; 2, 5 – surstyli and cerci; 3, 6 – praegonite. Scale bars: 0.5 mm (Figs. 1-2, 4-5); 0.1 mm (Figs. 3, 6).