DECEMBER 1991 195

RESEARCH ON THE SUBFAMILY TOXORHYNCHITINAE (DIPTERA: CULICIDAE) II-DESCRIPTION OF THE AFROTROPICAL SUBGENUS AFRORHYNCHUS SUBGEN. NOV?v2

H. RIBEIRO

Instituto de Higiene e Medicina Tropical, UniversidadeNova de Lisboa, Rua da Junqueira, 96-100, 1300 Lisboa, Portugal

ABSTRACT. The lutescensgroup of Edwardsis removed from the subgenusToxorhynchites and given subgenericrank. Four subgeneraare now recognized within the Toxorhyn- chites: Ankylorhynchus and Lynchiella, Neotropical; Toxorhynchites,Gondwanian, repre- sented in the Afrotropical Region by the brevipalpis group of Edwards; and Afrorhynchus subgen. nov., purely Afrotropical. The new taxon, typified by Toxorhynchiteslutescens, is describedand a key to all four subgenerais provided.

INTRODUCTION and, along with the Oriental christophigroup, may be consideredas one of the three groups The mosquito family Culicidae (Diptera) of the splendensseries (Steffan and Evenhuis includes the three subfamilies Anophelinae, 1985). The lutescensgroup, on the contrary, and Toxorhynchitinae (Edwards exhibits charactersthat clearly separateit not 1932). The latter, containing only the genus only from the brevipalpisgroup but also from ToxorhynchitesTheobald, haspredacious lar- all the other groupswithin the subgenusTox- vae which are potential agents of biocontrol orhynchites, as well as from the subgenera of other mosquitoes (Steffan and Evenhuis Ankylorhynchusand Lynchiella. Accordingly, 1981). Within the genus Toxorhynchites,the the lutescens group is removed from the following three subgeneraare currently rec- subgenusToxorhynchites and recognized as a ognized; Toxorhynchites,with about 50 spe- new subgenus,endemic to the Afrotropical cies and subspeciesoccurring throughout the Region. Oriental, Afrotropical and Australian regions, with some extensions into the Palaearctic; TAXONOMIC TREATMENT Lynchiella Lahille, with 14 speciesof the Neo- tropical Region; and Ankylorhynchus Lutz, Genus ToxorhynchitesTheobald with only four speciesof the Amazon basin (Brazilian Subregion of the Neotropical) SubgenusAfrorhynchus subgen. nov. (Knight and Stone 1977, Knight 1978, Ward (Figs. la,2a,3,5,7) 1984, Gaffrgan and Ward 1985). The Afrotropical speciesare currently clas- Type species.Toxorhynchites lutescens sifiedinto the brevipalpisand lutescensgroups Theobald, 190 1 (Edwards 194 1, Service 1990, Ribeiro 199 1a). The speciesof the brevipalpisgroup are very Diagnosis. 98: Mesokatepisternumwith, at near to those of the Oriental splendensgroup, least, a small patch of golden scalesbelow, usually also above; scaleson forecoxa all or almost all golden; hindfemur golden-scaled ’ ’ The first article of this seriesis publishedelsewhere. See beneath; laterotergite with few or no scales; Ribeiro 1991 a. lateral aspects of abdominal terga golden 2 Work supportedby the “Junta National de Investigacao Cientifica e Technologica (JNICT) and the “Centro de scaled;caudolateral tufts of abdominal terga DoencasInfecciosas e Parasitarias“(INIC). either golden, orange or red, never white, 196 MOSQUITOSYSTEMATICS VOL. 23, No. 3

2

b a -Q2mm b

6 8

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I I 0.lmm b a O.lmm DECEMBER199 1 197 brown or black; pale scales on abdominal is a wide dorsal aedeagalbridge, and a trans- sterna golden, never white. 9: maxillary pal- verse unsclerotized band is present on the pus short, only about 0.25 length of proboscis, paraproct. with rounded apex, and apparently made up As defined, Afrorhynchusis endemic to the of only 2 palpomeresowing to extreme reduc- Afrotropical Region and includes the follow- tion of palpomere 3; antenna normal, not ing species: Toxorhynchiteslutescens Theo- subplumose.8: tarsal claws of midleg small, bald, 1901, TX. aeneus (Evans 1926) TX. equal and simple;gonostylus widened at mid- erythrurus(Edwards 194 1), TX. kaimosi (Van dle; gonostylarclaw set at a right angle, blunt Someren 1946) TX. nairobiensis (Van So- tipped and long, from about 0.25 to almost meren 1946) TX. pauliani (Doucet 195 l), TX. 0.33 of gonostylus;dorsal bridge of aedeagus ruwenzori (Van Someren 1948) TX. viridi- wide or very wide; paraproct appearing di- basis(Edwards 1935), and a new, yet unpub- vided by a transverseunsclerotized band. lished speciesfrom the island of Sao Tome Etymology. The name of the new subgenus (Ribeiro 199 1b). refers to its geographicaldistribution and to The following provisional key will separate the peculiar shapeof the proboscisthroughout the four subgenera of the genus Toxorhyn- the genus. The three-letter abbreviation Aj-. chites,at least in the female. is recommended for this subgenus. Remarks. The of the Toxorhyn- chitinae at the genus-group level has been Key to the subgeneraof Toxorhynchites mainly based on the structure of the female maxillary palpi and antennae, which seem to Adults showthe most primitive (plesiomorphic)con- ditions in the Amazonian subgenusAnkylor- 1. 98: Mesokatepisternum with at least a hynchus.On the contrary, theseorgans exhibit small patch of golden scalesbelow, usu- an apparently derived (apomorphic) structure ally also above; scaleson forecoxa all or in the subgenus Toxorhynchitesand in the almost all golden; laterotergite with few new Afrotropical subgenus Afrorhynchus, or no scales.8: Midungues small, equal while the widespreadNeotropical Lynchiella and simple; gonostylus noticeably wid- has similar antennae and maxillary palpi of ened at middle; gonostylar claw long, an intermediate type. The distinction between from about 0.25 to almost 0.33 of gon- the new subgenusand the other three subge- ostylus;dorsal bridge of aedeaguswide; nera is quite clear. paraproctappearing divided into a prox- In Afrorhynchus,both sexeshave extensive imal and a distal portion by a narrow body areas clothed with golden scales, the unsclerotizedtransverse band. Afrotrop- caudolateral tufts are always golden, orange ical Region ...... Afrorhynch us or red in color, never white, black or brown, - . 98: Mesokatepisternumwithout golden and the laterotergite has few or no scales.In scales;scales on forecoxa all white; later- males, the midungues are small, equal and otergite densely clothed with scales.8: simple, the gonostylusis noticeably widened Midungues unequal, one of them at middle, the gonostylar claw is long, there toothed and stronger; gonostylar claw small, 0.13 to about 0.20 of gonostylus;

Figs. 1-8. Some subgenericcharacters of the genus Toxorhynchites.1, Structure of female maxillary palpi in Toxorhynchitesand Afrorhynchus(a), Lynchiella (b) and Ankylorhynchus(c), with proboscisfor comparison. 2, Midtarsal clawsof males in Afrorhynchus(a) and in the other subgenera(b). 3, Structureof aedeagusin Aj-orhynchus showing very large dorsal aedeagalbridge. 4, Aedeagusof TX. (Tox.) brevipalpisbrevipalpis Theobald (Maputo, Mozambique) showing narrow dorsal aedeagalbridge. 5, Gonostylus and gonostylar claw of TX. (Afr.) lutescens (holotype) showingwidened gonostylusand long gonostylarclaw characteristicof Aj-orhynchus.6, Gonostylusand gonostylarclaw of TX. ( Tox.) phytophygusTheobald (Mbandaka, Zaire). 7, Paraproctof TX. (Afi.) lutescens(holotype) showingunsclerotized transverse band characteristicof the new subgenus.8, Paraproct of TX. (Tox.) phytophygus (Mbandaka, Zaire). 198 MOSQUITOSYSTEMATICS VOL. 23, No. 3

dorsal aedeagal bridge narrow; para- Evans, A.M. 1926. Notes on Freetown mos- proct without unsclerotized transverse quitoes,with descriptionsof new and little- band _ ...... 2 known species.Ann. Trop. Med. Parasit. 2 9: Antenna subplumose,with long ver- 20:97- 108. ticilate hairs; maxillary palpus about as Gaffigan, T.V. and R. Ward. 1985. Index to long as proboscis, with 3 distinct pal- the secondsupplement to “A catalogof the pomeres, of which the apical one is the mosquitoesof the world,” with corrections longest, pointed and directed upward. and additions. Mosq. Syst. 17:52-63. Amazon basin (Brazilian Subregion of Knight, K.L. 1978. Supplement to “A Catalog the Neotropical) ...... Ankylorhynchus of the Mosquitoes of the World (Diptera: - . 9: Antenna normal, not subplumose; Culicidae).” Thomas Say Found. 6 maxillary palpusobviously shorter than (Suppl.):l-107. proboscis ...... ~ ...... 3 Knight, K.L and A. Stone. 1977. A catalog of 3. 9: Maxillary palpus about 0.67-0.75 the mosquitoesof the world (Diptera: Cul- length of proboscis, blunt tipped, and icidae). 2nd ed. Thomas Say Found. 6:1- with 3 distinct palpomeres,of which the 61 1. second is the longest. Neotropical Ribeiro, H. 199 la. Researchon the mosquito Region, with extensions into the subfamily Toxorhynchitinae (Diptera, Cul- Nearctic ...... Lynchiella icidae). I-The Afrotropical group brevi- - . 9: Maxillary palpuswith only 2 distinct palpis (adults). Arq. Mus. Bocage, N. Ser., palpomeres and shorter, about 0.25 of 213l-62. proboscis. Oriental, Afrotropical and Ribeiro, H. 199 1b. On the terrestrial and riv- Australian regions,with extensionsinto erine fauna of Sao Tome and Principe. VI. the Palaearctic ...... Toxorhynchites Arq. Mus. Bocage.(In press). Service, M.W. 1990. Handbook of the Afro- ACKNOWLEDGMENTS tropical toxorhynchitine and culicine mos- quitoes,excepting Aedes and Culex. British The writer is grateful for the facilities pro- Museum (Natural History), London. vided by all curators of the mosquito collec- Steffan, W.A. and N.L. Evenhuis. 198 1. Bi- tions in the following institutions:British Mu- ology of Toxorhynchites.Ann. Rev. Ento- seum (Natural History), Institut Pasteur de mol. 26:159-181. Paris, Museum National d’Histoire Naturelle, Steffan, W.A. and N.L. Evenhuis. 1985. Clas- Paris, Museum Royal d’Afrique Centrale, sification of the subgenusToxorhynchites Belgium, and Office de la Recherche Scienti- (Diptera: Culicidae). I. Australasian, east- fique et Technique d’Outre Mer, Bondy, ern Palaearctic, and Oriental species France. groups.J. Med. Entomol. 22:42 l-446. Theobald, F.V. 1901. A monograph of the REFERENCES CITED Culicidae or mosquitoes. Vol. 1. British Museum (Natural History), London. Doucet, J. 195 1. Etudes des Culicides de la Ward, R. 1984. Second supplement to “A region de Vagaindrano (Diptera). Mem. catalog of the mosquitoes of the world” Inst. Sci. Madagascar(A) 6:83-l 14. (Diptera: Culicidae). Mosq. Syst. 16:227- Edwards, F.W. 1932. Genera Insectorum. 270. Diptera. Fam. Culicidae. Fascicle 194. Bel- Van Someren, E.C.C. 1946. Ethiopian Culi- gium. cidae. Tribe Megarhinini-notes and de- Edwards, F.W. 1935. Mosquito notes. XII. scriptions. Trans. R. Ent. Sot. Lond. Bull. Entomol. Res. 26: 127- 136. 97: 177- 186. Edwards,F. W. 194 1. Mosquitoes of the Ethi- Van Someren, E.C.C. 1948. Ethiopian Culi- opian Region. III-Culicine adults and pu- cidae:Some new mosquitoesfrom Uganda. pae. British Museum (Natural History), Proc. R. Entomol. Sot. Lond. (B) 17:128- London. 132.