Choerades nigrapex (Bigot, 1878), comb. n.

Londt, Jason G. H. & Dikow, Torsten, 2019, A review of Southern African Choerades Walker, 1851 with the description of a new species (Diptera, Asilidae, Laphriinae), African Invertebrates 60 (1), pp. 31-65 : 49-53

Choerades nigrapex (Bigot, 1878), comb. n. stat. rev. Figs 7, 9, 25, 28

Dasythrix ? nigrapex Bigot, 1878: 229-230.

Laphria aureopilosa Ricardo, 1900:171; 1925: 279; Oldroyd 1970: 227 (key); 1974: 102 (key). Syn. n.

Choerades aureopilosa : Londt 1977: 44 (fig. 1 ♂ terminalia).

Laphria variabilis Bromley, 1947: 112. Syn. n.

Notes.

With the discovery that Bigot’s (1878) Dasythrix nigrapex , subsequently synonymized with C. flavipes (Wiedemann, 1821) by Oldroyd (1974: 102), is actually a valid species identical to aureopilosa , it becomes necessary to stabilize the taxonomy by formally recognizing nigrapex as belonging to Choerades and synonymizing aureopilosa and variabilis with it. This action is regrettable as aureopilosa has been one of the more commonly referred to species in the Southern African fauna. Although the authors have only seen good photographs of the unique holotype (Fig. 25), housed in the Oxford University’s collection (OXUM), Zoë Simmons has been able to confirm that it conforms well with the following redescription based on material available to the authors.

Redescription.

Based on all material studied.

Head: Black, silver and gold pubescent, black and white setose. Antenna black, scape and pedicel black setose. Face black, gold pubescent. Mystax predominantly black (a few pale yellow setae may be present ventrally) with macrosetae confined to elevated parts of facial protuberance. Lateral parts of face with groups of glistening silvery scale-like setae. Frons and vertex fine gold pubescent, largely asetose except for black setae adjacent to eye margins. Ocellar tubercle prominent, weakly setose except for a pair of strong black ocellar macrosetae. Occiput silver pubescent, strongly setose (black dorsally, white ventrally). Palps black and white setose.

Thorax: Black, silver pubescent, black, white and pale yellow setose. Cervical sclerite entirely black setose. Mesonotum apubescent, predominantly pale yellow (some ♂) or black (♀ and some ♂) setose. Lateral macrosetae predominantly black (a few yellow may occur) (1-2 notopleurals, 3 supra-alars, 3 postalars). Scutellum black, apubescent, fine pale yellow (♂) or black (♀) setose, c. 8-10 apical scutellar macrosetae, pale yellow (♂) or black (♀). Pleura silver pubescent, fine black and white setose. 1-2 black anepisternal macrosetae. Katatergal setae well-developed, mostly black (dorsally) and pale yellow (ventrally). Anatergites weakly silver pubescent, weakly yellow setose laterally.

Legs: Predominantly black with proximal parts of femora and tibiae orange (to varying degrees). Coxae silver pubescent, white setose. Trochanters weakly white setose. Femora and tibiae black and pale yellow setose, tarsi black setose.

Wings (Fig. 7): Length (humeral crossvein to tip) x breadth (maximum): ♂ 7.3 × 3.0 - 8.9 × 3.5 mm (mean - 5 specimens - 8.1 × 3.2 mm), ♀ 7.2 × 2.8 - 10.1 × 3.6 mm (mean - 5 specimens - 8.8 × 3.2 mm), females on average slightly bigger than males. Veins dark red-brown to black, membrane transparent, distal two-thirds orange-brown microtrichose, basal cells almost devoid of microtrichia except distally.

Abdomen: Black, moderately long, pale yellow (♂) or short black (♀) setose. T1 with a group of pale yellow (♂) or white (♀) white discal macrosetae.

Terminalia: ♂ terminalia as in Fig. 9 (previously published as fig. 1 by Londt (1977)). Sternite 10 uniquely equipped with a well-developed distal lobe. Hypopygium rotated through 180°. Note: In contrast to other Southern African species nigrapex not only possesses a lobed S10, but lacks long isolated gonocoxal setae proximally. In addition the gonocoxites appear completely fused midventrally.

Material examined.

SOUTH AFRICA: 2♀ 'South Africa: Natal / Kosi Bay - Estuary [c. 26°53'32"S, 32°52'41"E 15m] / 2632DD 16-19.iii.1982 / Coll: D.A. Barraclough / Indigenous Bush area’, NMSA-DIP-08854 & NMSA-DIP-81687 (NMSA); 1♀ 'South Africa: Natal / Kosi Bay Nat. Reserve [c. 26°55'55"S, 32°50'50"E 15m] / 2632DD 30.xi - 2.xii.82 / Londt, Barraclough & / Stuckenberg Forest / & open woodland areas’, NMSA-DIP-08855 (NMSA); 1♂ 2♀ 'S Africa: KwaZulu-Natal / Kosi Bay Nature Res. / 26°57'21"S, 32°49'51"E / 10-15.xii.2010 37m / JGH Londt Dune Forest’, NMSA-DIP-81690-2 (NMSA); 1♂ 'S Africa: KwaZulu-Natal / Kosi Bay Nature Res. / 26°57'21"S, 32°49'51"E / 20.ii.2011 JGH Londt / 35m Mixed Dune Forest’ NMSA-DIP-81693 (NMSA); 4♂ 'S Africa: KwaZulu-Natal / Kosi Bay Nature Res. / 26°57'46"S, 32°48'35"E / 9-13.x.2011 JGH Londt / 20m Picnic area Sandy / mixed savanna’, NMSA-DIP-81694-7 (NMSA); 1♂ 'South Africa: Natal / Makaheli For. [c. 26°57'49"S, 32°45'04"E 60m] 2632DD / ca. 5km NE Manguzi / 30. xi– 2.xii.1982 / Barraclough, Londt & / Stuckenberg Forest’, NMSA-DIP-08827 (NMSA); 1♀ 'S Africa: KwaZulu-Natal / Kosi Bay Nature Res. / 26°57'50"S, 32°48'41"E / 19 & 20.ii.2011 J Londt / 25m Mixed Dune Forest, / Woodland & Savanna’, NMSA-DIP-81699 (NMSA); 3♂ 3♀ 'S Africa: KwaZulu-Natal / Kosi Bay Nature Res. / 26°57'52"S, 32°48'51"E / 15-16.xii.2010 6m / JGH Londt Lake Shore / Dune Forest & Woodland’, NMSA-DIP-81700-5 (NMSA); 1♀ 'South Africa Ntl / Kosi Bay 26.58S / 32.48E 10-11.ii. / 1990 CD Eardley’, SANC-DIPT-02343 (SANC); 2♀ 'S Africa: KwaZulu-Natal / Manguzi Forest Reserve / 26°59'32"S, 32°43'25"E / 13-16.xii.2010 61m / JGH Londt Sand Forest’, NMSA-DIP-81706-7 (NMSA); 1♂ 'South Africa, Kwa- / Zulu. Lake Sibaya / E. Shore, 27.22S / 32.43E. 18-20.i. / 1981. R. Oberprieler’, 'National Coll. / of Insects / Pretoria. S. Afr.', SANC-DIPT-02274 (SANC); 1♀ [now without terminalia], 'Manguzi [c. 27°00'00"S, 32°45'28"E 30m] River / Nr. Maputa, Zululand / Nov.-Dec. 1945 / H.W. Bell Marley’, DMSA-DIP1005 (DMSA)*; 1♀ 'Mkuzi FT/AX 11/12/2004 /27.74696S, 32.29093E [c. 27°44'49"S, 32°17'27"E 50m] / Acacia xanthophloea / Pan-trap 6 Yellow / Earth Watch Team 8 / f287', NMSA-DIP-81708 (NMSA); 1♂ 1♀ 'S Africa: KwaZulu-Natal / Greater St. Lucia Wetland / Park Cape Vidal Camp / 28°07'25.6"S, 32°33'23.7"E / J.G.H. Londt 13.iii.2004 / 29m Dune forest edge’, NMSA-DIP-15031 [♂] NMSA-DIP-81709 [♀] (NMSA); 1♂ 'S. Africa: Natal / St. Lucia Estuary / [c. 28°22'00"S, 032°25'00"E] 9-10 Feb / 1974 A.B. Gurney’ USNMENT01384114 (USNM); 1♀ 'S Africa: Natal #3 / Nseleni Nature Res. / 28°41'S, 32°03'E 100m / Date: 10.i.1994 / Natal Museum Expedition / Forest and margins’, NMSA-DIP-08842 (NMSA); 1♀ 'South Africa: Natal / Richards Bay area / 3205E 2850S [c. 28°46'51"S, 32°02'18"E 360m] 21.ii.82 / PE Reavell 250 m’, 'Edge of / swamp / forest / tree’, NMSA-DIP-81712 (NMSA); 1♂ 'Ngoye forest [Reserve c. 28°50'34"S, 31°42'09"E 395m] between / Eshowe & Empangeni / Zululand. S. Africa / Stuckenberg / February 1957', 'Laphria / nigribimba Brom. / det. H. Oldroyd, 1963', NMSA-DIP-08800 (NMSA)*; 2♂ 'South Africa: Natal / Ngoye Forest Reserve ca. 28°51'S, 31°44'E [c. 395m] / Coast Scarp For. 250m / J. Londt 29.i.1988', NMSA-DIP-08843 NMSA-DIP-81714 (NMSA); 1♂ 'South Africa: Natal / Entumeni Nature Res. / 28°52'35"S, 31°22'54"E [c.710m] / J. Londt 26.i.1988 / Coast Scarp For. 720 m’, NMSA-DIP-08836 (NMSA); 1♀ ‘1174’, 'Eshowe [c. 28°53'41"S, 31°27'38"E 515m] / 11-16 / Marley’, 'Laphria / flavipes / ♀ Wied’, 'Ricardo / determ.', 'Not flavipes / Laphria sp. ign. / ♀ AJH’, 'Laphria aureopilosa’, ‘SAM-DIP-A007967’ (SAMC); 1♂ 'So. Africa: Natal, 1,5km / E. Mtunzini 2831Dd / Umlalazi Nature Res. [c. 28°57'19"S, 31°46'02"E 5m] / Feb. 1979 R.M. Miller / indig. For., Malaise tr.', NMSA-DIP-08828 (NMSA); 1♀ 'So. Africa: Natal, 1,5km / E. Mtunzini 2831Dd / Umlalazi Nature Res. / Nov. 1978 R.M. Miller / indig. For., Malaise tr.', NMSA-DIP-08826 (NMSA); 1♀ 'South Africa: Natal / Umlalazi Nature Res. / 26-27.i.1987 / JGH Londt SE2831DD / Dune forest & margin’, NMSA-DIP-08838 (NMSA); 5♂ 'South Africa KZN / Amatigulu Nature Res / 29°07'03"S, 31°35'39"E / J&A Londt 3 xi 2016 / 40m Coastal forest’ NMSA-DIP-81720-4 (NMSA); 1♀ 'Tugela River / mouth [c. 29°13'12"S, 31°30'18"E 20m]/ Natal / 29.3.1963 / T.W. Schofield’, 'Laphria / flavipes Wied. / det. H. Oldroyd, 1963', NMSA-DIP-08825 (NMSA)*; 1♂ 'South Africa: Natal / Pietermaritzburg / Townbush Valley [c. 29°33'39"S, 30°19'34"E 910m] / RM Miller + malaise / December 1976', NMSA-DIP-08840 (NMSA)*; 1♀ 'South Africa: KZN / Doreen Clark Nat. Res. / 29°34'43"S, 30°17'21"E / JGH Londt 12.i.2018 / 1125m Mistbelt forest’ NMSA-DIP-81727 (NMSA); 2♀ 'H.C. Burnup / Tongaat [c. 29°35'17"S, 31°05'07"E 100m], ‘08–9’, NMSA-DIP-08824 & NMSA-DIP-81728 (NMSA); 1♀ 'Hawaan Forest [c. 29°42'32"S, 31°05'28"E 70m] / Nr Umhlanga 10/12/98 / 29°05'24"S, 31°05'24"E, 'Coll. AP Leftwich’ NMSA-DIP-08857 (NMSA); 1♂ ‘687’, 'KKloof [c. 29°46'21"S, 30°49'49"E 435m] / Marley / 12.15', 'Ex descry / Laphria / nigrapex / ♂ (Big.) / AJH’, SAM-DIP-A007968 (SAMC); 1♂, 'Durban [c. 29°51'S, 31°01'E 5m], Natal / 16.III.1975 / R.K. Brooke’, DMSA-DIP1003 (DMSA)*; 1♀, 'Durban, Natal / 13.4.1974 / R.K. Brooke’, DMSA-DIP1004 (DMSA)*; 1♂ ‘235’, 'Marley / Stella B[ush] [? Pigeon Valley Nature Reserve c. 29°51'53"S, 30°59'13"E 95 m] / 2 –1915’, NMSA-DIP-08809 (NMSA)*; 1♂, 'Durban, / Natal / 6 –10– 21 / C.N. Barker / Stella / 3731', 'Laphria / variabilis / n. sp. / Det / S.W. Bromley 1947 ', 'Holotype / Laphria / variabilis / S.W. Bromley [red]', DMSA-DIP1008 (DMSA)*; 1♂ 'Marley / 2-1915 / Stella B’, SAM-DIP-A007961 (SAMC); 1♂ 'Bluff [c. 29°55'19"S, 31°00'18"E 30m] / 8-8-25 / HWB-M’, 'SW Bromley / Collection / 1955' ‘3267’, NMSA-DIP-08817 (NMSA)*; 1♂ 'Durban / Natal / 12.3.20 / C.N. Barker / Bluff / 2533', 'Paratype / Laphria / variabilis / Bromley [red]', DMSA-DIP1216 (DMSA)*; 1♀ 'Durban / Natal / 4.12.20 / C.N. Barker / Bluff / 2588', 'Paratype / Laphria / variabilis / Bromley [red]', DMSA-DIP6929 (DMSA)*; 1♂ 'Durban / Natal / 7.12.21 / C.N. Barker / Bluff / 2758', 'Paratype / Laphria / variabilis / Bromley [red]', DMSA-DIP6930 (DMSA)*; 1♀ 'Durban / Natal / 25.3.21 / C.N. Barker / Bluff / 2644', DMSA-DIP1007 (DMSA)*; 1♀ 'Durban / Natal / 1-2-19 C.N. Barker / Bluff / 2368', SAM-DIP-A007962 (SAMC); 1♂ 'Bluff / 18-1-17 / C.N. Barker / A. No: 2001', SAM-DIP-A007964 (SAMC); 1? [♂ lacking terminalia], 'Winklespruit [c. 30°06'17"S, 30°51'10"E 20m] / 25.12.18 / C.N. Barker / Ac. No. 2328', DMSA-DIP1006 (DMSA)*; 1? [♀ lacking terminalia], 'Winklespruit / 21.12.18 / C.N. Barker / Ac. No. 2328', DMSA-DIP1002 (DMSA)*; 1♀, 'Park Rynie [c. 30°19'04"S, 30°44'22"E 25m] / Natal / 23.12.20 / C.N. Barker / 2595', 'Allotype / Laphria / variabilis / S.W. Bromley [red]', DMSA-DIP6928 (DMSA)*; 2♀ 'Sth Africa: KZ-Natal / Southbroom Frederika / Trail J&A Londt 5m / 30°55'23"S, 30°19'10"E / 19.i.2014 Dune forest’ NMSA-DIP-81733-4 (NMSA); 1♂ 1♀ 'South Africa KZ-Natal / Mpenjati Nature Reserve / Yengele Trail & Beach 5m / 30°58'09"S, 30°17'03"E [c. 20m] / J&A Londt 21.iii.2010 / Dune Forest & Margins’ NMSA-DIP-81735-6 (NMSA); 1♂ 2♀ 'Sth Africa: Cape Prov / Goukamma Nature Res. [c. 34°02'27"S, 22°51'51"E 140m] / 34°02'S, 22°57'E / 25.xii.1988 / JGH Londt Macchia / Sandy ground & shrubs’, NMSA-DIP-08830 [1♀] NMSA-DIP-81737-8 (NMSA); 1♂ 'Sth Africa: Cape Prov / Plettenberg Bay area / Robberg [c. 34°06'14"S, 23°23'44"E 110m] 8.xii.1988 / 34°03'S, 23°22'E / JGH Londt On tall / shrubs in Nat Reserve’, NMSA-DIP-08835 (NMSA). ZIMBABWE: 1♀ 'N. Vumba [Mountains c. 19°04'37"S, 32°45'36"E 1290m], / S. Rhodesia / 15.10.1965 / D. Cookson’, 'Laphria / flavipes Loew / det. H. Oldroyd, 1972 / small specimen’, NMSA-DIP-08818 (NMSA)*; 1♂ 'N. Vumba, / S. Rhodesia / 30.10.1965 / D. Cookson’, NMSA-DIP-08839 (NMSA)*; 1♂ 'N. Vumba, / S. Rhodesia / 8.10.1964 / D. Cookson’, NMSA-DIP-08831 (NMSA)*; 1♂ 'N. Vumba, / S. Rhodesia / 4.10.1964 / D. Cookson’, 'Laphria / bella Loew / det. H. Oldroyd, 1972', NMSA-DIP-08808 (NMSA)*; 1♀ 'N. Vumba, / S. Rhodesia / 21.3.1966 / D. Cookson’, NMSA-DIP-08802 (NMSA)*; 1♂ 'N. Vumba, / S. Rhodesia / 13.3.1965 / D. Cookson’, NMSA-DIP-08832 (NMSA)*; 1♀ 'N. Vumba, / S. Rhodesia / 4.iv.64 / D. Cookson’, NMSA-DIP-08833 (NMSA)*; 1♀ 'N. Vumba, / S. Rhodesia / 7.10.1964 / D. Cookson’, NMSA-DIP-08834 (NMSA)*; 1♀ 'Vumba / Umtali Dist. / Feb. 1932 / P.A.S.', 'Collection / Transvaal / Museum’, 'Laphria / flavipes Wied. / det. H. Oldroyd, 1972', NMSA-DIP-08837 (NMSA)*; 1♀ 'Mt Selinda [c. 20°25'02"S, 32°41'38"E 1170m] / S. Rhodesia [Zimbabwe] / Nov. - Dec. 1930 / R.H.R. Stephenson’, SAM-DIP-A007966 (SAMC); 1♀ 'Mt. Selinda / 3.2.54 / N.J. Myers’, 'Laphria / flavipes Wied. / det. H. Oldroyd, 1963', NMSA-DIP-08829 (NMSA)*.

Additional material not personally studied.

Holotype ♂. SOUTH AFRICA: Labels attached to specimen - 'Holo- / type [circular with red edge]', 'Dasythrix / nigrapex. / 222 in / Coll. / Bigot’, 'Coll. Bigot. / abt. 1845-93. / Pres 1913 by / J.E. Collin’, 'ex. Hope-Westwood / Ox. Uni. Mus. of / Nat. Host. (OXUM)'. The specimen is housed in a drawer accompanied by the following label '222 D? nigrapex ♂ / g. Maira? (Schin.) / Natal. Port. J. Bigot’. Port Natal is an early name for the coastal city of Durban [c. 29°51'S, 31°01'E 5m].

In addition the senior author has seen photographs of the following specimens, identified as aureopilosa , which should now be allocated to nigrapex . SOUTH AFRICA: 1♂ 'Type [circular, red edge]', 'Durban [c. 29°51'S, 31°01'E 5m] / [illegible]', 'Laphria / aureopilosa / n.sp. Type ♂ / GR31.5.00', 'S. Africa / Distant Coll. / 1911-383', 'Holotype [circular, stuck to label] / Holotype / Laphria / aureopilosa Ricardo / det. J.E, Chainey, 1984', ‘NHMUK012810868’ (BMNH); 1♂ 'Bluff / Durban / 25-ii. 16 / C.N. Barker’, 'Presented / from / Durban Coll. / Per / GR / 26.7.91 [poor writing]', 'Laphria / variabilis Bromley / Det. H. Oldroyd. 1958 / topotypical’, 1 spec. 'Port St. John [31°38'S, 029°32'E] / Pondoland / Dec. 1923', 'S. Africa / R.E. Turner / Brit. Mus. / 1924-54', ‘NHMUK012810869’ (BMNH); 1♂ 'Durban, Natal, 24.02.19, C.N. Barker / Bluff [sideways] / 2499 [sideways]', 'Presented / from / Durban / Museum / Per CNB [?] / 10.1.23', ‘NHMUK012810870’ (BMNH).

Distribution, phenology and biology.

A relatively well-collected species with a fairly extensive distribution ranging from the eastern highlands of Zimbabwe through much of coastal South Africa, including KwaZulu-Natal, Eastern Cape and the southern coastal region of the Western Cape (Fig. 28). Data indicate that adults have a relatively long period of activity ranging from September through to April, with a peak in December (Table 1). The species inhabits coastal and mist-belt forests with adults frequently found sunning themselves on vegetation. C. nigrapex occurs in three biodiversity hotspots sensu Conservation International. It occurs primarily within the Maputaland-Pondoland-Albany biodiversity hotspot and is also distributed within the Cape Floristic Region and Eastern Afromontane biodiversity hotspot, but also occurs outside of the latter hotspot. Little is known of their biology.