Eur. J. Entomol. 103: 163–182, 2006 ISSN 1210-5759 Redefinition of the Clusiinae and Clusiodinae, description of the new subfamily Sobarocephalinae, revision of the genus Chaetoclusia and a description of Procerosoma gen. n. (Diptera: Clusiidae) OWEN LONSDALE and STEPHEN A. MARSHALL Insect Systematics Laboratory, Department of Environmental Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada; e-mails: [email protected]; [email protected] Key words. Clusiidae, Clusiodinae, Clusiinae, Sobarocephalinae, Chaetoclusia, Trichoclusia, Chaetoclusiella, Procerosoma, Sobarocephaloides, Sobarocephala, revision Abstract. The higher classification of the Clusiidae is reviewed, and the family is divided into the subfamilies Clusiodinae, Clusi- inae and the new subfamily Sobarocephalinae, all of which are (re)defined. The newly defined Clusiinae includes the genera Phyllo- clusia Hendel, 1917, Tetrameringia McAlpine, 1960, Amuroclusia Mamaev, 1987, Clusia Haliday, 1838, Paraclusia Czerny, 1903, Alloclusia Hendel, 1917 and Apiochaeta Czerny, 1903. The Sobarocephalinae includes the genera Sobarocephala Czerny, 1903, Procerosoma gen. n., and Chaetoclusia Coquillett, 1904. The new genus Procerosoma is described for two species, Procerosoma alini (Shatalkin) comb. n. from Brazil and P. prominens sp. n. from Mexico. Sobarocephaloides Soós, 1962 is treated as a junior synonym of Sobarocephala, and Chaetoclusia is redefined to include the monotypic genera Chaetoclusiella Soós, 1962, syn. n. and Trichoclusia Soós, 1962, syn. n. Six new species of Chaetoclusia are described (C. centrofasciata sp. n., C. amplipenis sp. n., C. transversa sp. n., C. inbionella sp. n., C. flava sp. n., and C. furva sp. n.). Chaetoclusia bakeri peruana Hennig, 1938 is included as a junior synonym of C. bakeri Coquillett, 1904. The phylogeny of Chaetoclusia is discussed and a key is provided for its 13 species. INTRODUCTION Canadian National Collection, Ottawa (CNCI); Carnegie Museum of Natural History, Pittsburgh (CMNH); Entomo- Frey (1960) divided the Clusiidae into two subfamilies, logical Museum of Utah State, Logan (EMUS); Biological Col- Clusiinae (with one or more inclinate fronto-orbital bris- lection, University of Bielefeld (FBUB); Instituto Nacional de tles) and Clusiodinae (all fronto-orbitals reclinate). Later Biodiversidad, Santo Domingo de Heredia (INBC); Staatliches authors narrowed the Clusiinae to include only those Museum für Tierkunde, Dresden (SMTD); United States genera with the anterior fronto-orbital bristle inclinate National Museum, Washington, D.C. (USNM); Zoological (Sasakawa, 1977; Pitkin & Evenhuis, 1989; Figs 7, Museum, University of Moscow (ZMUM). 11–13). Male and female genitalic characters, however, Most specimens were pinned, either air-dried or prepared in a as well as previously unrecognized external morpho- critical-point drier. FBUB specimens were stored in alcohol. logical characters, suggest alternative subfamilial divi- Male and female genitalia were prepared by macerating abdo- mens in hot potassium hydroxide (10% solution) for 12–13 min, sions of the Clusiidae. We here redefine the existing sub- followed by washing in glacial acetic acid and deionized water. families, erect the new subfamily Sobarocephalinae, and Terminology follows that in Caloren & Marshall (1998), with revise Chaetoclusia Coquillett, 1904 and Procerosoma the exception of the pregonite and postgonite, which are illus- gen. n., which are the sobarocephaline genera other than trated in Figs 4 and 5. The M1+2 ratio is defined as the length of Sobarocephala Czerny, 1903. the ultimate section of vein M divided by the length of the Most previous treatments of the New World tropical penultimate section. Clusiidae have focused on the immense sobarocephaline Representatives of all clusiid genera were examined genus Sobarocephala, a frequently encountered genus of (excluding the fossil genus Electroclusiodes Hennig, 1965), as well over 200 Neotropical species. Chaetoclusia, in con- were representatives of all recognized sobarocephaline species (defined below) and a range of exemplars from possible out- trast, has received very little attention, because of the group families, including all families in the superfamily Opo- apparent rarity of species other than C bakeri Coquillett. myzoidea (in sense of McAlpine, 1989) except Xenasteiidae (cf. Six of the thirteen species of Chaetoclusia are described Papp, 1998). A phylogenetic hypothesis for the species of Chae- as new below, but the group’s biology or immature stages toclusia (Fig. 58) was generated through analysis of a morpho- remain unknown. Procerosoma is the least frequently logical character matrix (Table 2) using PAUP version 4.0b10 encountered New World genus of Clusiidae, with its two [Phylogenetic Analysis Using Parsimony (Swofford, 2003)], species known from only three specimens collected in using a simple heuristic search with all characters unweighted. Mexico and Brazil. To polarize characters, the lineage made up of Sobarocephala and Procerosoma was treated as the sister group to MATERIALS AND METHODS Chaetoclusia; this allowed for the construction of a hypothetical ancestor characterized by plesiomorphic states. Trees were Approximately 180 specimens were examined from the fol- drawn with the aid of Winclada (Nixon, 2002). lowing institutions: University of Guelph Insect Collection (DEBU); British Museum of Natural History, London (BMNH); 163 RESULTS indicating that this character has evolved at least twice in Redefinition of the subfamily Clusiodinae the family. Furthermore, although entirely reclinate fronto-orbitals were treated as the ancestral state for the Most members of the Clusiodinae (all genera excluding Opomyzoidea by McAlpine (1989), inclinate anterior the basal genus Allometopon Kertesz, 1906) form a bristles appear frequently throughout the superfamily, strongly supported clade defined by an antenna that arises being entirely absent only in the Opomyzoinea (Opo- at or below the midpoint of the head, a blunt and obtuse myzidae + Anthomyzidae) (McAlpine, 1989). Inclinate angulate extension on the outer surface of the pedicel, a anterior fronto-orbitals are most notably present in the reduced or absent extension on the inner surface of the Agromyzidae and Odiniidae, which are possibly the pedicel, a scutellum that is flat and longitudinally wrin- closest relatives of the Clusiidae, suggesting that these kled dorsally, an extremely reduced phallapodeme, an bristles are in the groundplan of the family. enlarged ejaculatory apodeme, fusion of the components Given the above uncertainties regarding the polarity of the phallus, loss of the epiphallus, loss of the postgo- and homology of the character previously used to define nite, loss of the lateral lobe of the distiphallus, articulation the Clusiinae (inclinate anterior fronto-orbital bristles), it of the hypandrial complex to the epandrium and annulus is not surprising to find that the subfamily as previously (and less so to the subepandrial sclerite), and fusion of the defined does not withstand scrutiny, and we were unable pregonite (which is lengthened and enlarged) to the to find any other reliable synapomorphies that would sup- hypandrium. Outside of this group, the pregonite is well port its monophyly. Within the Clusiinae, however, we defined and separate from the hypandrium (Fig. 5), with have found two well-supported clades that we here treat membranous or stronger sclerotized connections seen in as the Clusiinae in a narrowed sense and the new sub- only a few derived lineages. This group includes the family Sobarocephalinae. The relationships between the genera Clusiodes Coquillett, 1904, Craspedochaeta Czer- subfamilies of Clusiidae are currently unresolved. ny, 1903, Hendelia Czerny, 1903, Heteromeringia Czer- The redefined Clusiinae includes Clusia Haliday, 1838, ny, 1903, Prohendelia Frey, 1960, Tranomeringia Sasa- Paraclusia Czerny, 1903, Apiochaeta, Alloclusia Hendel, kawa, 1966 and Xenoclusia Frey, 1960. 1917, Phylloclusia Hendel, 1917, Tetrameringia McAl- The entire subfamily, comprised of the above genera pine, 1960, Amuroclusia Mamaev, 1987, and at least two plus Allometopon, is less well supported. Synapomor- undescribed genera. The Clusiinae in this revised sense is phies of the entire subfamily include longitudinally seg- supported by six synapomorphies: the M1+2 ratio of the mented (not spherical and undifferentiated) spermathecae, wing is less than 2.7 (reversed in several species); the loss of the ventrolateral lobes of the hypandrium, entirely fore femur has several outstanding bristles on the postero- reclinate fronto-orbital bristles and loss of the presutural dorsal surface; the pleuron has a subnotal stripe (obscured intra-alar bristle. The latter two characters are of or lost in several genera); the surstylus has developed an equivocal polarity. Presutural intra-alars have also been internal spur (lost in several species, possibly absent in lost in Chaetoclusia richardfreyi (Soós, 1962), Sobaro- the ancestor of Phylloclusia and Tetrameringia); the disti- cephala (regained in several species) and most Apio- phallus is elongate and bent or jointed medially; the chaeta Czerny, 1903, and they also reappear in several vertex has a posteromedial truncate notch behind the species of Craspedochaeta. This character is also subject ocelli (also found in Allometopon). to frequent homoplasy in related families, as these bristles are often reduced in the Anthomyzidae, and are lost in the Sobarocephalinae subfam.