Orthotrichia Eaton 1973

Wells, Alice & De Moor, Ferdinand C., 2020, Hydroptilidae (Trichoptera) of Angola, a new genus, seven new species, and five new records, Zootaxa 4868 (4), pp. 495-514 : 506-507

Genus Orthotrichia Eaton 1973

Our literature study of descriptions of males of the 34 species of Orthotrichia presently recorded from Sub-Saharan Africa suggested a number of possible synonymies. It seemed these may have arisen as a consequence of the remarkable complexity and asymmetry of the male genitalia of some of the equatorial African species, rendering almost impossible the alignment of genitalic preparations for exact or even comparable ventral, dorsal or lateral views for description. Male genitalia of a number of species show very close similarities. Nonetheless, examination of a number of type species on loan from RBINS and RMCA, gave a better appreciation of the variability among the Central African species in this genus, confirming close similarities between some species, but also consistent differences. Thus, we are satisfied that Or. petiti Jacquemart 1962 from Zaire, Or. nova Marlier 1978 described from Mali; Or. spinicauda Kimmins 1958 from Zimbabwe; Or. verbekei Jacquemart 1957 from (now) Democratic Republic of Congo ( DRC); Or. guinkoi Guenda 1996 , Or. dapola Guenda 1996 , Or. mussoi Guenda 1996 , and Or. cazaubonae Guenda 1996 , from Burkina Faso; and Or. gudiel Malicky 2015 and Or. thariel Malicky 2015 from Ethiopia are all valid species. We were unable to access the types of one Angolan species, Or. benguelensis Marlier 1965 [1966], deposited by Marlier in the Museu do Dundo. However, types available from RBINS of Or. kivuensis Jacquemart 1956 are clearly conspecific with Or. sanya Mosely 1948a , Or. kivuensis is here recognised to be a junior synonym of Or. sanya .

Diagnostic features for Orthotrichia species are the form of the final instar larva and its case; and in the male genitalia the characteristic phallus, straight, cupped apically and unadorned by any distal spines or spurs, but usually with a median titillator; and much-reduced inferior appendages with a pair of (usually) slender, membranous lobes, variously termed ‘bilobed processes’, ‘setal lobes’ or ‘basal processes’, arising dorsally at the base of the inferior appendages and each bearing an apical seta. At the base of the unit formed by the inferior appendages and bilobed processes, a slender apodeme, extends anteriorly in the IXth segment, but does not reach the proximal margin of the segment. Often the inferior appendages are fused, and the bilobed processes are modified: one or both may be strongly asymmetrical. The female terminalia usually form a short, often stout, oviscapt, generally with a ventral cleft in the distal margin of abdominal sternite VIII, often around a small ventral gland in the centre and with a row of setae on the distal margin.

Hydroptila trifurcata Jacquemart 1962 is here referred to Orthotrichia , with Orthotrichia hydroptiloides Wells & Andersen 1995 , from Morogoro in Tanzania, recognised here as a junior synonym. This species is listed in Pseudoxyethira in the Trichoptera World Checklist, but we are unable to trace the author of the changed combination. Examination of the types of Hydroptila trifurcata , in the RBINS, from ‘ Congo, Katanga’ (now DR Congo)—‘ Holotype: 1 exemplaire [dissected, on 4 slides], paratypes: 8 exemplaires en préparations microscopique’ ( Jacquemart 1962: 4) reveals that the slide labelled ‘Type’ is of a female of Orthotrichia , and that five slides labelled ‘Paratype’ are of male specimens or parts of males, sharing diagnostic features of Orthotrichia . Two further slides of ‘Paratypes’ bear specimens (three specimens in total) conspecific with the ‘Type’ female.

A number of the African species of Orthotrichia , including 2 of the new species described here, share the features of the widespread Or. angustella -group ( Marshall 1979) ‘characterised by the development of the lateral processes of segment IX in the males and the row of subcostal scales on the forewings of males of most species’ (see Fig. 44 ).

Figures

FIGURES 37–44. Orthotrichia spp.: 37–39, Orthotrichia mlamboi sp. nov, [CAW 855M], male genitalia: 37, ventral; 38, dorsal; 39, left lateral. 40–44, Orthotrichia ferreirae sp. nov., male [CAW 757AW]: 40, phallus, ventral; 41, ventral; 42, dorsal; 43, left lateral, slightly skewed. 44, forewing costal scales.Abbreviations: IX, X = abdominal segment IX and tergite X; b. pr. = bilobed process; inf. app. = inferior appendage (paired); lt. lb. IX = lateral lobe of segment IX (paired); me. ap. = mesoventral apotome at base of inferior appendages and bilobed process; me. lb. = medial lobe on segment VIII; pr. = paramere; ph. = phallus; sp. IX = spine on tergite IX; tl. = titillator.