Notiochyromya sp. D

Ebejer, Martin J., 2009, A revision of Afrotropical Chyromyidae (excluding Gymnochiromyia Hendel) (Diptera: Schizophora), with the recognition of two subfamilies and the description of new genera, African Invertebrates 50 (2), pp. 321-321 : 349-351

Notiochyromya sp. D

These specimens belong to a yellow species with the scut having no additional marginals and no short discal setae but, as in filigera and monticola , there is a pair of setae on the disc just medial and posterior to the subapical pair; scutal setulae between dc lines in 10 rows; mtn dark brown; abdomen with segments 3–7 having paired brown spots laterally. It is not included in the above key for lack of easily defined characters. Material examined: NAMIBIA: 1^Windhoek, Hoffnung farm, lucerne fields, 7.ii.1972, British Museum Southern African Expedition 1972 (dry-pinned, BMNH). ZIMBABWE: 1^Zambezi, Rutometje-Res. St. RM2, 16°10'S: 29°25'E, vii.1988, J. Weyrich (in alcohol, ZSMC).

Genus Oroschyromya gen. n.

Type species: Oroschyromya peruncinata sp. n., here designated.

Etymology: From the Greek oros (mountain), indicating the occurrence of the majority of species of the genus at high altitudes, and Chyromya , denoting the affinity to this genus.

Diagnosis: Head broader than thorax; fr narrow with moderate to strongly converging margins; eye oval, lying oblique in profile; ocp slightly convex with a few setulae on disc; femora long and slender; a well-developed post ia present; scut without additional marginals or setulae on disc; apicoventral seta on mid tibia absent; ep large, more or less rectangular and sits vertically relative to the long axis of the abdomen; cerc modified and prg large, heavily sclerotized, conical to pyramidal.

The autapomorphies that characterize this genus include a strong post ia seta, very large vertically elongated ep, an intermediate sclerite between the posterior edge of hyp and prg, large mobile surs and prg, and modified cerc. In the female, segments 6 and 7 usually membranous dorsally, therefore appearing divided, with heavily sclerotized lateral sclerites that are also strongly setose, giving them the appearance of a second pair of cerc. In other respects, scutum and scut appear similar to those in Gymnochiromyia , but in this genus the head is not so broad, the post ia is absent and the male and female postabdomens present different character states.

Description:

Head: Broader than long; ocp flat in profile or only slightly convex, somewhat concave when viewed from above; fr broad at vertex and eyes strongly convergent; orbital plate distinct. Chaetotaxy: 3 strong orb more or less reclinate, but also lateroclinate, anterior orb inclinate or reclinate; pvt distinct and crossed; strong vti and vte; postocular setulae distinct, especially behind vt, others short, more or less in one row, lower postgenal seta present; mouthparts normal, palp round or almost round.

Thorax: Elongated, narrower than width of head. Chaetotaxy: prpl setula absent, 1 or 2 strong posterior dc, sometimes with 2–4 short dc anterior to these, scutal setulae between dc lines in 4–8 irregular rows with one short, but distinct prscut pair; 1–2 pprn, 1 posthu, 2 ntpl, 1 sa and 1 long pa, 1 post ia, absent pra; 2 pairs of marginal scut setae: one subapical and one basal, no setulae on margin or on disc; anepisternum with 1 strong seta at middle of posterior margin directed backwards, often with another shorter seta above, katepisternum with 1 or 2 strong setae at upper posterior corner; tuft of numerous, fine, long setulae at ventral aspect of katepisternum.

Wing: Hyaline or faintly and diffusely infuscated, R 4+5 and M 1+2 parallel to wing apex or very slightly convergent; vein closing anal cell often with a minute stump vein at middle; hu break present or absent, in which case a distinct weakening apparent, costal setulae with minute spine-like setulae interspersed among them along anterior margin of costal vein between R 1 and R 2+3, several similar short spine-like setulae present at irregular distances on dorsal aspect of costa.

Legs: Fine setulae scattered on all pairs, in addition longer setae present on fore femur; mid tibial apicoventral seta absent, femora not or hardly dilated, hind trochanter and tarsomeres not modified. One species has additional setal characters.

Abdomen: Variably compressed laterally; 6 visible tg, tg 6 narrow; st sclerotized, st 5 modified, st 6 often reduced to V-shaped sclerite.

Male postabdomen: ep well-developed, vertically elongated and variably compressed laterally with relatively large ventrally directed opening; cerc large sclerotized to a variable degree and usually with modified setae, either as 3–5 strong, but short spines in addition to fine setulae or longer and stronger setae than usual for family; hyp distinct with additional lateral sclerites between its posterolateral end and base of prg, ph apd long, narrow and free from hyp for a significant distance (cf. Chyromya and Somatiosoma ), ej apd small, not recognisable (or not sclerotized) in some species; distiph complex as usual for the family, with sclerotized and membranous components; prg heavily sclerotized, more or less conical that is, more like a large spine than a flat sclerite, with strong setae, psg distinct and sometimes remarkably modified.

Female postabdomen: Segments 6–8 variously modified, usually with one or more segments having tg divided into large heavily sclerotized lateral sclerites with strong setae, hypr distinct, s relatively small and very deeply pigmented; cerc tending to be elongate.

Distribution: Afrotropical ( Fig. 67 ).

Ecology: Oroschyromya is known only from Africa. The genus appears to favour wellvegetated habitats with a wide range of rainfall. All species but one are from high altitude (1200–3200 m). The single lowland (260 m) species ( O. dubia ( Lamb, 1914) from Mauritius and the Seychelles) is placed in this genus on the basis of strict character interpretation and postabdominal features of both sexes, but its general appearance is more like Notiochyromya or Gymnochiromyia .

Key to the species of Oroschyromya Males

1 prsut + 3–5 postsutural dc setae ........................................................................ 2

– prsut + 1–2 postsutural dc setae ........................................................................ 4

2 Cerci at least 3× longer than wide and ca 1/3 height of ep, viewed in profile; prg long and narrow, as long as or longer than cerci, postabdomen Figs 19a, b .......... ........................................................................................................ elongata sp. n.

– Cerci shorter, at most 1/4 height of ep; prg shorter and spine-like, clearly broader basally ................................................................................................................... 3

3 Metanotum dark brown; 1+4–5 dc, scutal setulae arranged in 8 irregular rows and numerous from anterior to posterior; post ia seta strong; tarsomere 5 of all legs brown, postabdomen Fig. 14 ............................................................ bicolor sp. n.

– Metanotum pale brown; 1+3 dc, scutal setulae arranged in 4–6 rows, sparse from anterior to posterior; post ia short; tarsomere 5 of all legs yellow, postabdomen Fig. 18 .............................................................................................. elgonae sp. n.

4 Scutum entirely pale yellow; wing hyaline .......................................................... 5

– Scutum with distinct longitudinal stripes; wing uniformly infuscated pale yellowish brown .................................................................................................................... 7

5 Head ca 1.5× as broad as long; post ia seta weak; surstylus narrow, only slightly curved from base to apex, postabdomen Fig. 16 ............................. dubia (Lamb)

– Head ca 2× as broad as long; post ia seta strong; surstylus in basal half broad and curved more-or-less at right angles, Figs 12d , 23b ............................................... 6

6 Surstylus not twisted along its long axis; psg very large with several lobes, angled at 90° medially, postabdomen Fig. 23 ...................................... peruncinata sp. n.

– Surstylus twisted along its long axis; psg much smaller, straight and blade-shaped, ơ postabdomen Fig. 12 ....................................................................... affinis sp. n.

7 Antenna entirely yellow; head with frontal setulae black; scutum with 4 brown stripes, legs with all tarsomeres yellow, postabdomen Fig. 22 ..... gracilipes sp. n.

– Third antennal segment brown; head with frontal setulae pale yellowish white, scutum with 6 longitudinal stripes; legs with distal three segments of all tarsomeres dark, ơ postabdomen Fig. 21 ......................................................... fusciceps sp. n.

Females [NB: females of O. elgonae , O. gracilipes and O. fusciceps remain unknown and are not included in this key.]

1 Tergite 6 divided dorsally, forming two large, disc-shaped divisions laterally; tg 4– 6 with very strong setae ........................................................................................ 2

– tg 6 normal; setae on apical segments of abdomen not unusually developed ...... 3

2 Segment 6 with 5 or 6 strong setae on each disc-shaped sclerite; segment 4 with very strong setae along entire posterior margin; segment 5 with strong setae medially, and following a short interruption, laterally on posterior margin, postabdomen Fig. 13 ............................................................................................................ affinis sp. n.

– Segment 6 with 2–4 strong setae on each disc-shaped sclerite; segments 4 and 5 with strong setae along edge of posterior margin, close-set dorsally and more widelyspaced along lateral edge of posterior margin .......................... peruncinata sp. n.

3 0+1–2 dc; scutal stripes absent and metanotum entirely yellow, postabdomen Fig. 17 ......................................................................................................... dubia (Lamb)

– 1+3–5 dc; scutum and metanotum not as above ................................................... 4

4 Scutum with dark brown longitudinal stripes that may be confluent anteriorly; stripes extend to lateral aspect of scutellum leaving only middle 1/3 yellow; metanotum brown; abdominal tg dark brown, postabdomen Fig. 15 .................. bicolor sp. n.

– Scutum yellow, if with stripes, then these narrow and predominantly on posterior half, not extending onto scutellum; metanotum yellow (occasionally brown); abdominal tg yellow or brown, if the latter, then often with brown marking divided centrally leaving a pale yellow line on apical tg 1–3, postabdomen Fig. 20 .......... ........................................................................................................ elongata sp. n.

Figures

Fig. 67. Distribution of Oroschyromya gen. n.

Fig. 19. Oroschyromya elongata sp. n., ơ: (a) hypopygium, lateral, scale bar = 0.2 mm; (b) sternites 5 & 6, ventral, scale bar = 0.15 mm.

Fig. 14. Oroschyromya bicolor sp. n., ơ: (a) hypopygium, lateral; (b) distiph, lateral; (c) st 5, ventral. Scale bars = 0.2 mm.

Fig. 18. Oroschyromya elgonae sp. n., ơ: (a) hypopygium, lateral; (b) distiph, lateral. Scale bar = 0.2 mm.

Fig. 16. Oroschyromya dubia (Lamb), ơ: (a) head, lateral; (b) st 5, ventral; (c) hypopygium, lateral; (d) ej apd, dorsal; (e) distiph, lateral. Scale bars = 0.3 mm in Fig. 16a and 0.2 mm in Figs 16b–e.

Fig. 12. Oroschyromya affinis sp. n., ơ: (a) apex of hyp, lateral; (b) prg, lateral; (c) psg, lateral; (d) surs, lateral; (e) same, posterior. Scale bars = 0.1 mm. (See Fig. 23 for comparison.)

Fig. 23. Oroschyromya peruncinata sp. n., ơ: (a, b) head lateral and anterior, scale bar = 0.2 mm; (c) postabdomen, lateral, scale bar = 0.3 mm; (d) postabdomen, posterior, scale bar = 0.25 mm; (e) part of internal hypopygium, lateral, scale bar = 0.05 mm; (f) surs, lateral, scale bar = 0.1 mm.

Fig. 22. Oroschyromya gracilipes sp. n., ơ: (a) hind leg, anterior aspect; (b) basitarsus, middle leg, lateral; (c) hypopygium, lateral; (d) distiph, lateral; (e) st 5, lateral; (f) same, ventral. Scale bars = 0.3 mm in Figs 22a–c and 0.2 mm in Figs 22d–f.

Fig. 21. Oroschyromya fusciceps sp. n., ơ: (a) hypopygium, lateral; (b) distiph, lateral. Scale bar = 0.15 mm.

Fig. 13. Oroschyromya affinis sp. n., ^postabdomen: (a) ventral, (b) lateral, (c) dorsal. Scale bar = 0.2 mm.

Fig. 17. Oroschyromya dubia (Lamb), ^postabdomen, lateral (a) and ventral (b). Scale bar = 0.15 mm.

Fig. 15. Oroschyromya bicolor sp. n., ^postabdomen, dorsal (a) and ventral (b). Scale bar = 0.35 mm.

Fig. 20. Oroschyromya elongata sp. n., ^postabdomen: (a) lateral, (b) ventral, (c) dorsal. Scale bars = 0.35 mm.