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 )

The higher classification of the Clusiidae is reviewed, and the family is divided into the subfamilies Clusiodinae, Clusiinae and the new subfamily Sobarocephalinae, all of which are (re)defined. The newly defined Clusiinae includes the genera Phylloclusia 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.

indicating that this character has evolved at least twice in the family.Furthermore, although entirely reclinate fronto-orbitals were treated as the ancestral state for the Opomyzoidea by McAlpine (1989), inclinate anterior bristles appear frequently throughout the superfamily, being entirely absent only in the Opomyzoinea (Opomyzidae + Anthomyzidae) (McAlpine, 1989).Inclinate anterior fronto-orbitals are most notably present in the Agromyzidae and Odiniidae, which are possibly the closest relatives of the Clusiidae, suggesting that these bristles are in the groundplan of the family.
Given the above uncertainties regarding the polarity and homology of the character previously used to define the Clusiinae (inclinate anterior fronto-orbital bristles), it is not surprising to find that the subfamily as previously defined does not withstand scrutiny, and we were unable to find any other reliable synapomorphies that would support its monophyly.Within the Clusiinae, however, we have found two well-supported clades that we here treat as the Clusiinae in a narrowed sense and the new subfamily Sobarocephalinae.The relationships between the subfamilies of Clusiidae are currently unresolved.
The redefined Clusiinae includes Clusia Haliday, 1838, Paraclusia Czerny, 1903, Apiochaeta, Alloclusia Hendel, 1917, Phylloclusia Hendel, 1917, Tetrameringia McAlpine, 1960, Amuroclusia Mamaev, 1987, and at least two undescribed genera.The Clusiinae in this revised sense is supported by six synapomorphies: the M1+2 ratio of the wing is less than 2.7 (reversed in several species); the fore femur has several outstanding bristles on the posterodorsal surface; the pleuron has a subnotal stripe (obscured or lost in several genera); the surstylus has developed an internal spur (lost in several species, possibly absent in the ancestor of Phylloclusia and Tetrameringia); the distiphallus is elongate and bent or jointed medially; the vertex has a posteromedial truncate notch behind the ocelli (also found in Allometopon).

Sobarocephalinae subfam. n.
The new subfamily Sobarocephalinae includes the genera Sobarocephala, Chaetoclusia and Procerosoma, the latter two of which we revise below.Sobarocephaloides Soós, 1964 is synonymized with Sobarocephala, and the monotypic Chaetoclusiella Soós, 1962 andTrichoclusia Soós, 1962 are synonymized with Chaetoclusia (see below).This subfamily is defined by male genitalic characters: loss of the sixth spiracle (otherwise left lateral on the annulus), a ventral lobe of the hypandrium that is usually at least as long as the hypandrial arm (secondarily reduced in several species of Chaetoclusia and Sobarocephala), and a relatively large surstylus (usually more than 0.67 times the length of the epandrium, but smaller in Procerosoma alini (Shatalkin, 1991) and several species of Sobarocephala).Large surstyli are also found in Alloclusia, Allometopon, and certain clades within several clusiodine genera.
Procerosoma and Sobarocephala share a number of synapomorphies, including an open cell bm (confluent with cell dm), a small pregonite, and (possibly) a loss of the presutural intra-alar bristle.Procerosoma, however, lacks the basal shield on the distiphallus and the thumblike process on the lateral lobe of the distiphallus, both of which characterize Sobarocephala.Although Procerosoma and Sobarocephala are sister groups, Procerosoma is here given generic status for practical reasons.It would have been extremely difficult to provide a definition for Sobarocephala including Procerosoma because there are no apparent synapomorphies of both genera that have been retained in every species of Sobarocephala.Furthermore, Procerosoma lacks dorsal preapical tibial bristles, similar to Heteromeringia and most genera of Clusiinae, and Procerosoma is easily recognized in that the head is relatively wide with the mouthparts situated more ventrally and posteriorly, most dimensions of the body are elongate with respect to those of Sobarocephala, and the scutellum and metatergites have become distinctly convex, slightly shortened, and angled dorsally.

Status of the genus Sobarocephaloides
Sobarocephaloides discolor Soós, 1964 (the type species of Sobarocephaloides by monotypy; Holotype label data: Costa Rica.La Suiza, 26.x [year not given], P. Schild (1%, USNM)) belongs to the Sobarocephala plumata clade of the S. flaviseta species group (which will be revised in an upcoming paper) on the basis of a frons that is strongly narrowed posteriorly, minute ocellar bristles, a slight protuberance on the face below and between the antennal bases, a distinct brown spot on the first flagellomere and a densely plumose arista.The first character is a synapomorphy of the S. flaviseta species group, and the latter four are synapomorphies of the S. plumata clade.Sobarocephaloides is therefore synonymized with Sobarocephala.Soós (1964) erected the genus Sobarocephaloides for Sobarocephala discolor based on a reduction of the postvertical, fronto-orbital and anterior dorsocentral bristles.It is now apparent that a reduction of the bristles on the head and thorax is characteristic of most species in the S. plumata clade, of which S. discolor is an extreme example.A second species, Sobarocephaloides alini Shatalkin, 1991, was described as a Sobarocephaloides on the basis of a similar reduction of the bristles on the head and thorax (Shatalkin, 1991), but it is only remotely related to S. discolor.Sobarocephaloides alini is discussed below as the type species for the new genus Procerosoma.
Etymology.The generic name is Latin for "slender-bodied"; gender female.
Chaetotaxy.Bristles yellow.Anterior and mid frontoorbital bristles close to each other on anterior margin of frons, with hind bristle on posteromedial margin; mid fronto-orbital bristle 0.8 times length of remaining frontoorbitals or extremely reduced and setulae-like (Figs 1, 6 and 7).Acrostichal, ocellar, and postvertical bristles absent.Pedicel with one outstanding dorsal bristle.Two postsutural dorsocentral bristles with anterior bristle 0.6-0.8times length of posterior bristle, sometimes with small bristle in front of anterior dorsocentral.Presutural dorsocentral and presutural intra-alar bristles absent.Scutellum wide, short and angled dorsally, with one pair of strong cruciate apical bristles and 0-2 pairs of weak lateral bristles.One strong anepisternal and katepisternal bristle; proepisternal bristle small.Preapical tibial bristles absent.Male mid femur with at least six stout ctenidial bristles basally.One postpronotal and two notopleural bristles; two postsutural intra-alar bristles; intra post-alar bristle absent.
Female abdomen.Tergites 1 and 2 fused; sternite 1 reduced to thin, weakly sclerotized strip; tergites 3 to 6 and sternites 2 to 6 complete.Abdomen past segment 6 narrowed into long, thin tube; segments separated by long membranous area nearly equaling segment length.Sternite 8 bifid on distal fourth and divided lengthwise by median desclerotized line.Length of cercus approximately 0.67 times that of sternite 8. Spiracles in membrane below tergites on segments 1 to 7. Spermathecae (two) weakly sclerotized, spherical, smooth-surfaced and almost 0.33 times length of sternite 8 (Fig. 9).Spermathecal ducts thin, weakly sclerotized and eight times length of spermatheca.Ventral receptacle weakly sclerotized, sac-like and recurved ventrally.Ventral receptacle and reproductive ducts opening close together into anterior end of genital chamber.

(Figs 1-5)
Sobarocephaloides alini Shatalkin, 1991: 928-930.Redescription (Fig. 1) Male.Body length 4.0 (female) -5.3 mm (male).Arista sparsely short-plumose.Small bristle in front of anterior dorsocentral.Mid fronto-orbital bristle 0.8 times length of remaining bristles.One pair of lateral scutellar bristles.Scutum yellow with one pair of stripes extending presuturally along dorsocentral line, thinned medially behind suture on outer face.Scutellum yellow.Metatergites yellow with one pair of faded stripes lateral to scutellum and one faded stripe below.Pleuron yellow.Legs yellow with fore tibia brown (darkest basally) and fore tarsi brown.Head predominantly yellow; sides of face with wide brown stripes; ocellar tubercle brown; bulbous distal portion of genal process white.Head strongly swollen and 1.2 times width of scutum; gena with prominent process (swollen distally); face not produced.Abdomen black with epandrium and surstylus dark yellow to orange.Wing yellowish/dusky with distal fifth lightly clouded.M1+2 ratio 3.0.

Female.
As described for male except as follows: head and notum subequal in width; genal process absent; tergites 1-4 black; tergite 5 with wide central stripe (narrowing anteriorly); remainder of abdomen yellow; wide truncate notch present behind ocelli; frons and face bulging; lateral scutellar bristle absent.
Male terminalia .See generic description.Female terminalia not dissected.
Comments.Shatalkin (1991) described Procerosoma alini as a Sobarocephaloides (now a synonym of Sobarocephala) on the basis of a single pair of dorsocentral bristles.We have, however, found two pairs of dorsocentral bristles in the paratype female and a second pair of sockets in the holotype male where the anterior dorsocentrals had broken off.
See comments for Procerosoma prominens.
Procerosoma prominens sp.n.   (Shatalkin, 1991) male, genitalia.2 -terminalia, posterior; 3 -terminalia, left lateral (shaded hypandrium inserted; D = dorsal, V = ventral, A = anterior, P = posterior); 4 -hypandrial complex, anterior; 5hypandrial complex, left lateral.orbital bristles broken off (reconstructed in illustrations based on diameter of sockets).Two pairs of weak lateral scutellar bristles.Scutum yellow with one pair of stripes extending presuturally along dorsocentral line, with stripes thinned medially behind suture on outer face; posterior margin of notopleuron with brown line reaching longitudinal dorsocentral stripe.Scutellum yellow with lateral margin brown.Metatergites yellow with katatergite and anatergite below scutellum brown (faded medially).Pleuron yellow with thin line extending from postpronotum along anterior suture of anepisternum to lateral diagonal suture of katepisternum.Legs yellow except as follows: fore tarsi brown excluding basal 2/3 of first tarsomere; mid and hind tarsi brown distally on all tarsomeres.Head predominantly yellow; sides of face with one pair of wide dark yellow stripes; gena white and silvery-tomentose; stripe on outer-dorsal surface of first flagellomere; back of head with one pair of large lateral spots; ocellar tubercle brown.Gena relatively high with posterior angle distinctly produced.Vertex projecting and face strongly carinate.Head as wide as scutum.Abdomen yellow except as follows: posterior-lateral corners of tergite 1 brown; tergites 2-6 with large spot along posterior margin (wide apical emargination on tergites 2 and 3); tergite 7 with light brown, transverse, lateral stripe.Wing narrowly infuscated around dm-cu and darkly clouded apically.M1+2 ratio 4.6.
Male unknown.
Etymology.The specific name refers to the characteristic structure of the face (L."to stand out", "to extend").
Comments.Procerosoma prominens is most easily separated from P. alini as follows: the arista is densely plumose, the first flagellomere has a dorsolateral stripe, the mid fronto-orbital bristle is minute, there are two pairs of lateral scutellar bristles, the gena is silvery-tomentose and a brown vertical stripe is present anteriorly on the pleuron.Furthermore, the face of this species is strongly carinate dorsally and deeply recessed ventrally, and the gena is high and acutely projecting on the posterior angle.
Two eggs (Fig. 10) were found in the abdomen of the holotype and are described above in the generic description.

Diagnosis
Cell bm closed.Vein R1 setulose dorsally.Gena usually shiny.Anterior lateral scutellar bristle minute to absent.Two postsutural dorsocentral bristles, sometimes with one weak to well-developed bristle directly in front of anterior dorsocentral.Presutural dorsocentral and presutural intraalar bristles absent.Sternites 6 and 7 of annulus atrophied into thin but well-sclerotized ventral band.Mid tibia with preapical dorsal bristle.

Generic description
Adult.General.Length 3.0-5.4mm.Body slender, colour yellow with brown to black pattern.Angular extension on outer face of pedicel acute and longer than wide; inner face with angular projection acute to 90° and broadly rounded at apex.Arista black with base white; usually sparsely long or short-plumose (sometimes densely long-plumose).Gena and parafacial shiny to microsetulose or silvery tomentose.Frons shiny with sides parallel to slightly divergent anteriorly.Halter white to light yellow.Wing length 2.5-3.0 times width.Sub- Chaetotaxy.Bristles yellow to black.Anterior and mid fronto-orbital bristles close to each other on anterior margin of frons with hind bristle on posteromedial margin; sometimes with additional reclinate bristle between mid and hind bristles; bristles subequal in length.Ocellar and postvertical bristles divergent and strong to minute or (occasionally) absent.Pedicel with one outstanding dorsal bristle.Prescutellar acrostichal bristle usually absent.Two postsutural dorsocentral bristles with anterior bristle usually 0.6-0.8times length of posterior bristle, sometimes with small bristle in front of anterior dorsocentral.Prescutellar acrostichal bristles usually absent.One postpronotal and two notopleural bristles; two intra-alar bristles; one minute intra post-alar bristle.One strong anepisternal and katepisternal bristle; proepisternal bristle small.Scutellum with one pair of long cruciate apical bristles and one pair of short lateral bristles (sometimes with one pair of additional minute bristles anteriorly).Mid tibia with dorsal preapical bristle; fore and mid femora of male with posteroventral row of ctenidial bristles.
Male abdomen.Tergites 1 and 2 fused; sternite 1 reduced to thin, weakly sclerotized band; tergites 3 to 6 and sternites 2 to 5 complete.Spiracles in membrane below tergites 1-5 and ventrally between tergites 6 and 8. Abdomen encircled by annulus comprised of sternites 6-8; sternite 8 setose and dorsal (with right lateral extension); sternites 6 and 7 forming narrow, heavily sclerotized ventral band with membranous attachment between sternites 6 and 8. Epandrium dome-shaped.Surstylus at least 0.75 times height of epandrium and usually rounded apically; tubercles on inner face along apex and at least distal half of posterior margin.Cerci setulose, rounded, lobate, and slightly projecting.Hypandrium with one pair of arms articulating with subepandrial sclerite, which in turn articulates with epandrium; hypandrium with one pair of parallel ventrolateral lobes ("ventral lobe of hypandrium") that lie on either side of phallapodeme; medial two bristles on ventral lobe often close and long and third bristle distal and small to absent.Phallapodeme long and thin, articulating with basiphallus and thin anterior-transverse portion of hypandrium to form lever; articulation with hypandrium facilitated by suspended ventral plate on phallapodeme.Pregonite usually large, setulose, and round or clavate (small and rectangular with two setulae in one species).Postgonite usually round and small with several distal setae.Basiphallus "C" shaped, smooth and often curved medially.Epiphallus absent or small; fin-like and occasionally lengthened.Distiphallus never longer than phallapodeme.Ejaculatory apodeme 0.33 times length of phallapodeme; width approximately 0.2 times length.
Of the synapomorphies listed above (characters 1, 2, 3 and 12), the presence of setulae along vein R1 is the most easily observed and does not appear to have become reversed in any species.The presence of these setulae also appear to be a unique synapomorphy within the Clusiidae, although Craspedochaeta novaeguineae Soós, 1962 (Bismarck Islands, New Guinea) has two or three setulae on R1 near its junction with the costa.The reduction of the annulus and the anterior lateral scutellar bristle are good diagnostic characters, but these states occur independently in a number of Sobarocephala, occasionally in tandem.Male unknown.

Key to the species of Chaetoclusia
Female terminalia (Fig. 29).Spermatheca unpigmented and lightly sclerotized.Spermathecal duct 5 times length of spermatheca and also lightly sclerotized.Ventral receptacle approximately 0.8 times length of spermathecal duct and not recurved ventrally; gradually constricted to base.Comments.This distinctive species is known from two females collected from widely separated localities in Brazil.Chaetoclusia richardfreyi is relatively large and robust, characterized by strong acrostichal, ocellar, lateral scutellar, and postvertical bristles, as well as an additional reclinate bristle inserted between the mid and hind frontoorbitals (Fig. 11).Furthermore, the presutural intra-alar bristle is absent (at least weakly developed in all other species of Chaetoclusia) and the ventral receptacle is not small and recurved, but elongate, straight and only gradually constricted towards the base (Fig. 29).

Redescription (Figs 13 and 15)
Male.Body length 5.3 mm.Bristles black.One strong bristle in front of anterior dorsocentral.Acrostichal bristle absent.Anterior lateral scutellar bristle small but well developed.Arista sparsely plumose.Postvertical and ocellar bristles well developed.Anterior genal bristle strong and vibrissa-like; remaining genal bristles small and thin.Two short, but strong bristles in front of presutural intra-alar bristle.Thorax yellow.Coxae and legs yellow with hind tibia brown.Head yellow with ocellar tubercle brown and frons brownish-orange centrally.Abdomen dark brown.Wing with band from CuA1 to R2+3, curving distally to meet costa; band extending along wing tip to R4+5 posteriorly.
Male terminalia not dissected.Female.Externally as described for male except stripe on frons wider and abdominal segment 8 and terminalia yellow.
Female terminalia not dissected.Comments.Chaetoclusia sabroskyi, like C. richardfreyi, is relatively large and robust with well-developed bristles, but it is further characterized by a yellow thorax (Fig. 15), one pair of short, strong bristles in front of the presutural intra-alar bristle and a strong anterior genal bristle (Fig. 13).
Male unknown.
Female terminalia not dissected.
Comments.Chaetoclusia nigromaculata can be readily separated from congeners by its distinct notal pattern (Fig. 16).Comments.We have not seen the holotype, but its description agrees entirely with the paratypes examined.

Chaetoclusia transversa sp. n.
(Figs 21, 30-32, Map 2) Description (Fig. 21) Male.Body length 3.3-4.8mm.Cephalic bristles light brown with remaining bristles dark brown.Acrostichal bristles absent.Anterior dorsocentral bristle 0.75 times length of posterior bristle, or if small additional bristle present anteriorly, that bristle half length of anterior dorsocentral, which is half length of posterior dorsocentral.Presutural intra-alar bristle weak.Arista sparsely plumose.Postvertical bristle minute.Ocellar bristle small and thin.Anterior lateral scutellar bristle absent.Scutum brown with wide transverse yellow stripe at level of suture; postpronotum sometimes yellow.Scutellum and metatergites brown.Pleuron mostly yellow, with posterior half of anepisternum brown.Legs yellow with tip of hind femur, fore and hind tibiae, and fore tarsi brown.Head yellow with first flagellomere white, ocellar tubercle brown, and back of head with one pair of stripes and one spot below ocellar tubercle.Abdomen yellow with tergites 3-6 brown.Wing clouded lightly along apex and in first radial cell.One male and one female paratype from Peru with brown spot reduced on anterior margin of scutum and with large yellow spot on apex of scutellum; additional male paratype from Peru with brown anterior spot nearly absent and posterior brown stripe widely emarginate anteriorly.One male from Costa Rica (INBC) differing as follows: stripes behind head attached dorsally and extending around base of reclinate orbital and hind fronto-orbital bristles; transverse yellow stripe thin; tergites 2-6 dark brown.
Female.Externally as described for male.
Male terminalia .Length of epandrium 0.6 times height; width 0.9 times height.Surstylus curved inwards in cross-section; truncate with anteroventral corner projecting; tubercules on inner anteroventral face.Cerci slightly elevated; bristles short and subequal in length.Hypandrial arm curved medially, narrow basally, and bulbous distally; one short and one minute bristle distally on ventral lobe of hypandrium.Basiphallus small and thin.Epiphallus as long as basiphallus, well sclerotized basally and curved distally.Pregonite elongateglobose with two minute basal bristles.Postgonite well developed.Distiphallus 0.75 times length of ejaculatory apodeme; medially with one pair of bulbous, spinulose  lateral swellings; lateral lobe widest distally and nearly half length of distiphallus.
Female terminalia not dissected.
Etymology.The specific name refers to the transverse yellow stripe on the scutum.
Comments.The yellow transverse stripe on the scutum of Chaetoclusia transversa is unique within Chaetoclusia and a good diagnostic character (Fig. 21).The male terminalia is distinct in that the apex of the surstylus is truncate and strongly curved in cross-section and the pregonite is reduced in size with only two bristles (a similar pregonite is found in Procerosoma and most Sobarocephala) .
Female unknown.
Male terminalia .Terminalia elongate, with apex of surstylus nearly reaching sternite 2 in repose.Epandrium as wide as high and length 0.6 times height.Surstylus 1.2 times height of epandrium, posteriorly lobate and tapered distally.Cerci projecting, rounded, as wide as long and with one longer pair of bristles medially.Hypandrial complex relatively elongate.Phallapodeme well developed with distal head relatively bulbous.Hypandrial arm highly reduced; ventral lobe of hypandrium sinuate on anterior and posterior faces and with one pair of minute bristles medially and distally.Pregonite ovate with numerous setulae on distal half.Postgonite elongate, nearly perpendicular to long axis of complex with minute bristles along length.Distiphallus 0.6 times length of phallapodeme and curved distally; lateral lobes short, pointed and joined to distiphallus by membranous enclosure.
Etymology.The specific name refers to the size of the male terminalia.
Distribution.Southern Mexico (Map 2).Holotype.Mexico.Chiapas: El Trifundo (49 km S Jaltenango), 13.-15.v.1985, 1300-2000  Comments.Chaetoclusia amplipenis, C. longefilata and C. inbionella are monophyletic on the basis of characters of the male genitalia: the terminalia are elongate, almost reaching sternite 2, and the arms of the hypandrium are strongly reduced.These species also have a dark dorsal stripe on the first flagellomere, but this can be found in C. quadrivittata as well.Chaetoclusia amplipenis can be separated from the above species by a largely piceous abdomen, one lateral scutellar bristle and no additional process on the lateral lobe of the distiphallus.It is also the only species, aside from the widespread C. bakeri, to be found in Mexico.Melander & Argo, 1924 (Figs 20, 36-38, Map 2) Chaetoclusia longefilata Melander & Argo, 1924: 8-9.Redescription (Fig. 20 large brown dorsal spot on first flagellomere; ocellar tubercle brown.Abdomen yellow except as follows: tergites 3, 4, 6, annulus, and epandrium brown; tergite 5 with posterior margin brown centrally.Wing infuscated in first and second radial cells (excluding base) and very lightly clouded in third radial cell and along apex.
Postgonite subrectangular with two distal bristles.Distiphallus 0.4 times length of phallapodeme; lateral lobe bifid with inner branch rounded and serrate.
Comments.While it appears as though Chaetoclusia longefilata and C. inbionella have a "thumb" on the lateral lobe of the distiphallus (Figs 36,39), it is more likely that the lateral lobe has become split medially.A "thumb" on the lateral lobe of the distiphallus is considered to be a synapomorphy restricted to the species of Sobarocephala.Description (Fig. 22)

Chaetoclusia inbionella
Male.Body length 3.4-4.1 mm.Bristles light brown.One small bristle in front of anterior dorsocentral.Acrostichal bristle absent.Arista sparsely pubescent.Presutural intra-alar bristle weak.Ocellar bristle present.Postvertical bristle absent.Anterior lateral scutellar bristle minute.Scutum yellow with anterior margin, postpronotum, and lateral margins to wing base light brown to brown; one pair of darker postsutural dorsocentral stripes present.Scutellum brown with thin median yellow stripe.Metatergites light brown lateral to scutellum or just on katatergite.Pleuron light yellow with anepisternum yellow.Legs yellow.Head mostly yellow; dorsal half of first flagellomere dark brown; face, gena, parafacial and occiput white; back of head with one pair of stripes (not extending to lateral margin); ocellar tubercle brown.Abdomen brown from tergite 3 to annulus; tergite 5 with anterior half yellow; epandrium with large brown basal spot; remainder of abdomen yellow.Wing clouded extensively along anterodistal margin , darkest towards costa.
Female.Externally as described for male except as follows: more darkly pigmented; sometimes hind tibia brown on basal 3/5; clypeus orange to brown; abdomen brown excluding anterior half of tergite 5 and terminalia; one female with anterior margin of scutum yellow and posterior corners brown, and with postsutural stripes reaching anterior margin of scutum.
Male terminalia .Terminalia elongate, with apex of surstylus nearly reaching sternite 2 in repose.Width of epandrium 0.7 times height and length nearly half height.Cerci small and lobate with numerous small bristles.Surstylus nearly triangular in outline with apex rounded, distal half tapered and posterior margin broadly rounded; inner face with minute basal process; tubercles along distal 3/4 of posterior margin.Hypandrial arm short and projecting at 90° from long axis; ventral lobe of hypandrium with two small bristles and one empty socket distally (only holotype dissected).Pregonite ovate and irregular in outline with several minute basal setulae.Postgonite as described for C. amplipenis.Epiphallus as large as basiphallus (viewed laterally).Distiphallus and lateral lobe as described for C. longefilata.
Female terminalia not dissected.
Etymology.The specific name refers to the collection from which the type series was borrowed.Comments.Chaetoclusia inbionella is sometimes patterned much like C. bakeri (Figs 18,22), but differs in having a sparsely pubescent arista, well developed ocellar bristles, an entirely light yellow pleuron and an entirely brown first abdominal tergite.
Chaetoclusia centrofasciata sp.n. (Figs 17,(42)(43)(44)Map 2) Description (Fig. 17) Male.Body length 4.8 mm.Bristles brown.Two dorsocentral bristles.Acrostichal bristle absent.Arista missing.Anterior lateral scutellar bristle minute.Postvertical bristle minute.Ocellar and presutural intra-alar bristles missing in specimen, but sockets well developed.Scutum yellow with supra-alar spot and central stripe brown; stripe with two pairs of yellow presutural internal spots.  2 (9 external and 10 male genitalic characters, described in Table 1).Characters were polarized using Sobarocephala and Procerosoma as an outgroup and a hypothetical ancestor was included in the analysis to root the cladogram (removed from the above phylogeny).Cladistic analysis was performed using PAUP [Phylogenetic Analysis Using Parsimony (Swofford, 2003)], with a simple heuristic search, and all characters unweighted.Length of tree 22 steps with a CI of 0. Female unknown.
Male terminalia .Epandrium as wide as high and length 0.8 times height.Height of surstylus 1.2 times that of epandrium; tubercles along inner-distal margin.Cerci projecting, deeply emarginate and pointed distally; bristles subequal in length.Hypandrial arm longer than ventral lobe of hypandrium and truncated distally; ventral lobe of hypandrium with one minute distal and two long medial bristles.Phallapodeme and basiphallus well developed.Pregonite membranous with three central bristles.Postgonite elongate and thin with two distal and three medial bristles.Epiphallus level with anterior face of basiphallus, well sclerotized, and with distal and posterior margins irregular.Distiphallus absent (see comments).Comments.The spots on the frons and the complete median stripe on the scutum are unique within Chaetoclusia, and can be used as reliable diagnostic features to identify this species (Fig. 17).Chaetoclusia centrofasciata also appears to be unique in that it has lost the distiphallus (Fig. 42), although this should be verified with the examination of more males.Elongation and elaboration of the postgonite possibly serves as a functional adaptation associated with this loss.Coquillett, 1904 (Figs 12, 18, 27, 45-47, Map 3) Chaetoclusia bakeri Coquillett, 1904: 94. Melander & Argo, 1924: 8. Chaetoclusia bakeri peruana Hennig, 1938: 92-94. Syn. n.Redescription (Figs 12 and 18) Male.Body length 3.6-5.4mm.Bristles yellow.One small bristle in front of anterior dorsocentral.Acrostichal bristle absent.Arista densely plumose with hairs black and flattened.Anterior lateral scutellar bristle minute.Postvertical and ocellar bristles minute.Presutural intraalar bristle weak.Scutum yellow with two pairs of thin lateral stripes (outer stripe continuous with lateral margin), each pair joined anteriorly and posteriorly; sometimes enclosed yellow stripe faded medially, particularly around transverse suture; sometimes brown pattern faded around area of notopleuron and postpronotum (particularly in those specimens collected in Venezuela and Central America); specimen from Mexico with inner pair of stripes broken medially.Scutellum yellow with one pair of lateral brown stripes.Metatergites brown, sometimes yellow below scutellum.Pleuron light yellow with anepisternum, anepimeron, and proepisternum brown; anepisternum centrally with yellow longitudinal stripe, sometimes bordered ventrally by brown longitudinal stripe (variably faded).Legs light yellow with hind tibia brown on (at least) basal half, excluding extreme base.Head mostly yellow; first flagellomere white with brown infuscation around base of arista; clypeus and lower half of face sometimes brown; ocellar tubercle brown.Abdomen brown with surstylus and lateral third of epandrium yellow; tergite 1 sometimes yellow.Wing clouded on distal third and lightly infuscated around cross veins.

Chaetoclusia bakeri
Female.Externally as described for male except as follows: face and clypeus always yellow; proepisternum sometimes yellow; tergite 1 rarely yellow; anterior half of tergite 4 yellow; tergite 6 sometimes yellow laterally; tergite 7 light brown; tergite 8 and terminalia yellow.
Male terminalia .Length of epandrium 0.6 times height; width 0.7 times height.Height of surstylus 0.6 times that of epandrium with anterior surface straight and posterior surface tapering distally; innerposterior margin tuberculate (excluding basal third); apex of surstylus sometimes thin and tapered.Cerci rounded, emarginate and setose with one pair of slightly longer bristles medially (sometimes small or folded backwards, appearing absent, as in figure).Ventral lobe of hypandrium with transverse wrinkles along anterior margin; hypandrial arm perpendicular to long axis of ventral lobe of hypandrium basally and parallel distally; three minute bristles present distally.Phallapodeme well developed with anterior face fused to hypandrium (separate in all other Chaetoclusia).Pregonite large, minutely setose and somewhat fused to hypandrium basally.Postgonite small.Basiphallus and epiphallus well developed.Distiphallus not much longer than basiphallus; wide basally and strongly tapered distally (appearing "spade"-shaped).
Female terminalia (Fig. 27) Spermatheca pale and weakly sclerotized.Spermathecal duct thin, poorly sclerotized and four times length of spermatheca.Comments.Chaetoclusia bakeri is characterized by a densely plumose arista and a reduction of the postvertical and ocellar bristles (Fig. 12).Chaetoclusia bakeri is also the most widespread and common species of Chaetoclusia on the continental mainland, with records not extending further from the coast than Trinidad or Barro Colorado Island.
The slight difference in thoracic colouration between the type specimen of the nominate subspecies (Coquillett, 1904) and the type specimen of the subspecies Chaetoclusia bakeri peruana Hennig, 1938 was exaggerated by the more extensive pigmentation on the anepisternum of Hennig's specimen, which revealed the unpigmented median longitudinal stripe on the sclerite.This median portion of the anepisternum is always unpigmented, but was not apparent on the specimen examined by Coquillett since the background of this sclerite was also yellow.The extensive new material available to us has shown that the thoracic pigmentation of C. bakeri is quite varied, with different phenotypes often occurring in the same localities.There is a similar amount of variation in wing pigmentation, which ranges from light to dark.Chaetoclusia bakeri peruana is therefore included here as a junior synonym of C. bakeri.Female.Externally as described for male except tergite 7 light brown and tergite 8 and terminalia yellow.

Chaetoclusia
Male terminalia .Epandrium as wide as high; length 0.67 times height.Surstylus 0.67 times height of epandrium and elongate triangular (broadly rounded apically); distal third of inner-posterior margin with stout, pointed tubercles; inner-basal face with short pointed spur.Cerci triangular with apical emargination; setose with one pair of longer central bristles.Hypandrium with ventral lobe and arm subequal in length; arm narrow medially and ventral lobe of hypandrium with one minute distal and two short medial bristles.Pregonite large and ovate with numerous central setulae.Postgonite and epiphallus well developed.Basiphallus saddle-shaped with slight dorsal arch.Base of distiphallus produced ventrally with ventral section 0.67 times length of dorsal section (from intersection with basiphallus); ventral section strongly curved; one pair of lateral spinulose swellings present medially; distally bifid and truncate; lateral lobe absent.
Female terminalia.As described for C. bakeri except spermathecal duct 2.5 times length of spermatheca.
Comments.Chaetoclusa xanthops is the only known species of Sobarocephalinae with pigmented spermathecae.
Chaetoclusia furva sp.n. (Figs 25,28,Map 1) Description (Fig. 25) Male.Body length 4.9-5.1 mm.Bristles light brown to dark brown.One small bristle in front of anterior dorsocentral.Acrostichal bristle absent.Presutural intra-alar bristle weak.Ocellar bristle minute.Anterior lateral scutellar bristle minute or absent.Arista sparsely plumose.Scutum yellow with notopleuron and one pair of wide postsutural stripes brown; sometimes scutum light brown laterally in front of notopleuron.Scutellum yellow, sometimes with one pair of lateral postsutural stripes.Metatergites yellow, sometimes with one pair of faded stripes lateral to scutellum.Pleuron and legs light yellow to white with fore tarsi light brown to brown, sometimes with fore tibia or all tibiae brown.Head yellow with ocellar tubercle light brown and head white below antenna, sometimes with first flagellomere narrowly infuscated around base of arista.Abdomen brown with tergite 1 and surstylus yellow, sometimes tergite 2 only brown posteriorly and laterally.Wing dusky on distal ¼ (darkest around R2+3).
Female.Externally as described for male except as follows: colour often darker; sometimes anterior half of tergite 5 yellow; tergite 8 and terminalia yellow.
Male terminalia.As described for C. flava.Female terminalia (Fig. 28).Spermatheca poorly sclerotized and with minute transverse wrinkles on basal third.Spermathecal duct up to half as wide as spermatheca and divided into two sections: basal section no more than 0.3 times width of spermatheca and approximately three times length of spermatheca; distal section wide, membranous and 1.2 times longer than spermatheca.Ventral receptacle approximately 1.5 times length of spermatheca; wide distally, sac-like and recurved ventrally.
Comments.Chaetoclusia furva is similar in appearance to C. flava, but it is distinguished by the derived female genitalia (Fig. 28) and differences in cephalic and notal colouration (see key) (Figs 25,26).These two species appear to be most closely related to C. xanthops, which is also Caribbean in distribution, on the basis of chaetotaxy, colouration, and numerous derived characters of the male genitalia (see Discussion).

PHYLOGENETIC DISCUSSION
Cladistic analysis of the character matrix in Table 2 using PAUP produced three equally parsimonious trees (22 steps in length, CI = 0.82, RI = 0.89), one of which (Fig. 55) was identical to the strict consensus tree.Synapomorphies of Chaetoclusia include a reduction or absence of the anterior lateral scutellar bristles (character 2), setulae along most of vein R1 (character 3), a reduction of sternites 6 and 7 of the annulus (character 11) and black bristles (character 1; reversed in most species).Excluding C. richardfreyi, Chaetoclusia is further characterized by the absence of prescutellar acrostichal bristles (character 6), three fronto-orbital bristles and weak to well-developed presutural intra-alar bristles.
The Caribbean species Chaetoclusia xanthops, C. flava, and C. furva comprise a well-supported clade related to the Central American and Ecuadorian species.These three species all have the ocellar bristles minute to absent (shared with C. bakeri), a weak presutural intra-alar bristle (also found in several other species of Chaetoclusia), a pleuron that is white to yellowish-white, a basal spur on the inner face of the surstylus, a pregonite that is lobate dorsally and somewhat fused to the hypandrium, a curved basiphallus and a distiphallus that is strongly recurved and produced ventrally (characters 5, 6, 7, 10, 13, 14 and 16, respectively).The consensus tree suggests that these Caribbean species plus C. bakeri (Central and South America) form a monophyletic group based on a reduction of the ocellar bristles (character 5), and together form the sister-group to C. centrofasciata (Ecuador) (Fig. 55), with which they share a loss of the lateral lobes of the distiphallus (character 17).This, however, is poor support for the clade because both of these characters reappear regularly throughout the Clusiidae, particularly within the Sobarocephalinae.We prefer a slightly less parsimonious arrangement in which C. xanthops, C. flava, and C. furva form a monophyletic group with the widespread Central and South American species C. transversa based on the presence of minutely spinulose, mediolateral swellings on the distiphallus (character 15), a novel character within the Clusiidae.The latter phylogeny (Fig. 56) is 1 step longer (24 steps) than the most parsimonious trees.Chaetoclusia longefilata appears to be most closely related to C. amplipenis and C. inbionella, as the males share extremely elongate terminalia (character 9) and a minute hypandrial arm (character 12).

DISTRIBUTION
Most species of Chaetoclusia appear to have narrow ranges within confined regions of Central America and the Caribbean (maps 1 and 2).Aside from C. transversa, which extends from Costa Rica and Panama to Peru, C. bakeri is the only species of Chaetoclusia to exhibit an extensive neotropical range (map 3).
The phylogenies outlined above (Figs 55, 56) suggest either a Caribbean or South American origin for Chaetoclusia, because all Central American taxa belong to a single clade for which Caribbean species form the first two outgroups.Furthermore, it appears as though once Chaetoclusia reached Central America from the Caribbean, the genus experienced a successful localized radiation with one lineage extending into Ecuador (C.
Body length 4.1-4.6 mm.Bristles black.Two dorsocentral bristles (subequal in length) plus one small bristle in front of anterior dorsocentral.Acrostichal bristle absent.Presutural intra-alar bristle strong.Arista sparsely short-plumose.Postvertical bristle absent.Ocellar bristle relatively long.Anterior lateral scutellar bristle minute.Scutum yellow with one pair of light brown postsutural stripes and with anterior and lateral margins of scutum

Fig. 55 .
Fig. 55.Phylogenetic hypothesis for species of Chaetoclusia selected from one of the 3 equally parsimonious trees calculated from the morphological character matrix in Table2(9 external and 10 male genitalic characters, described in Table1).Characters were polarized using Sobarocephala and Procerosoma as an outgroup and a hypothetical ancestor was included in the analysis to root the cladogram (removed from the above phylogeny).Cladistic analysis was performed using PAUP [Phylogenetic Analysis Using Parsimony(Swofford, 2003)], with a simple heuristic search, and all characters unweighted.Length of tree 22 steps with a CI of 0.82 and a RI of 0.89.Solid circles indicate unique characters, and open circles are homoplasies or character reversals.
Fig. 55.Phylogenetic hypothesis for species of Chaetoclusia selected from one of the 3 equally parsimonious trees calculated from the morphological character matrix in Table2(9 external and 10 male genitalic characters, described in Table1).Characters were polarized using Sobarocephala and Procerosoma as an outgroup and a hypothetical ancestor was included in the analysis to root the cladogram (removed from the above phylogeny).Cladistic analysis was performed using PAUP [Phylogenetic Analysis Using Parsimony(Swofford, 2003)], with a simple heuristic search, and all characters unweighted.Length of tree 22 steps with a CI of 0.82 and a RI of 0.89.Solid circles indicate unique characters, and open circles are homoplasies or character reversals.

Fig. 56 .
Fig. 56.Phylogenetic hypothesis for the species of Chaetoclusia if those species with lateral spinulose swelling on the distiphallus (character 15) are presumed monophyletic.Length of tree 23 steps (one step longer than the most parsimonious hypotheses).Solid circles indicate unique characters, and open circles are homoplasies or character reversals.
forest floor (1%, USNM).Body length 3.4 mm.Bristles light brown.Two dorsocentral bristles.Arista sparsely plumose.Ocellar bristle minute.Anterior lateral scutellar bristle minute.Scutum brown with central stripe and anterior margin of postpronotum yellow.Scutellum yellow with lateral corners brown.Metatergites yellow with one pair of brown stripes lateral to scutellum.Pleuron and legs white.Head yellow with ocellar tubercle light brown and with first flagellomere, face, gena and parafacial white.Abdomen brown with epandrium orange and surstylus and cerci white.Wing dusky on distal half in first and second radial cells.