Stilobezzia (Acanthohelea) thomasi, William L. Grogan & Spinelli & Ronderos & Carla, 2013

William L. Grogan, Jr., Spinelli, Ronderos, María M. & Carla, 2013, The biting and predaceous midges of Guadeloupe Diptera: Ceratopogonidae). I. Species of the subfamily Ceratopogoninae, Insecta Mundi 2013 (324), pp. 1-21 : 9-10

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Stilobezzia (Acanthohelea) thomasi

new species

Stilobezzia (Acanthohelea) thomasi new species

( Figs. 5-12 View Figures 5-12 , 21-23 View Figures 20-27. 20 )

Diagnosis. The only Neotropical species of Stilobezzia (Acanthohelea) with a uniformly dark brown thorax and scutellum with 6 large setae. Males have stout parameres with each half bearing an apical, hyaline pointed projection that is adpressed to the ventral surface and anteriorly directed, and their aedeagal sclerites are divided, sinuous, heavily sclerotized with a hyaline L-shaped mesolateral lobe bearing a foot-shaped distolateral projection that is apically pointed.

Female. Head ( Fig. 5 View Figures 5-12 ). Dark brown. Eyes very narrowly separated. Antenna with pedicel dark brown, flagellum ( Fig. 6 View Figures 5-12 ) uniformly brown; flagellomeres cylindrical, moderately elongated; antennal ratio 1.02- 1.06 (1.04, n=4). Palpus brown; segment 3 with shallow, subapical sensory pit bearing several capitate sensilla; palpal ratio 2.67-3.20 (2.96, n=10). Mandible with 7-9 large teeth on inner margin. Thorax. Uniformly dark brown; scutellum with 6 large setae. Legs ( Figs. 7-9 View Figures 5-12 ) brown, hind leg slightly darker; extreme bases of femora, tibiae slightly paler; hind tibial comb with 6 spines; hind tarsomere 1 with two rows of ventral palisade setae; prothoracic tarsal ratio 2.11-2.50 (2.23, n=10), mesothoracic tarsal ratio 2.25-2.87 (2.70, n=10), metathoracic tarsal ratio 2.33-2.70 (2.48, n=10); claws curved, greatly unequalsized on all legs, fore claws slightly longer than tarsomere 5, mid and hind claws slightly shorter than their respective tarsomeres 5. Wing ( Fig. 10 View Figures 5-12 ) membrane slightly to moderately infuscated; cubital fork originating distal to level of base of r-m crossvein; macrotrichia on costa, veins R 1 and R 3, sparse on margins of cells r 3 and m 1; second radial cell 2.67-3.80 (3.24, n=7) x longer than first; wing length 1.19– 1.40 (1.28, n=11) mm, width 0.45-0.52 (0.49, n=2) mm; costal ratio 0.71-0.75 (0.74, n=6). Halter pale brown. Abdomen. Dark brown; segment 10 and cerci paler. Genitalia ( Fig. 11 View Figures 5-12 ): sternite 8 as long as broad, ventral surface with 6 large setae and short dense setae on posterior half; anterior margin curved, lateral margins sub-parallel, posteromedian excavation V-shaped; sternite 9 divided into moderately broad halves, distal 1/3 slightly broader, apices bearing a slender pointed anteriorly directed process; sternite 10 with 3 pairs of setae, cercus rounded. Two ovoid, slightly unequal spermathecae with short narrow necks, measuring 51-59 (54, n=10) by 37-44 (40, n=10) μ m, and 42-55 (49, n=10) by 32-37 (35, n=10) μ m.

Male. Similar to female with the following notable sexual differences. Antennal flagellomere 13 greatly elongated, 1.5 x longer than 12; plume dark brown, dense; antennal ratio 0.87-1.06 (0.96, n=9). Palpal ratio 2.67-3.28 (3.00, n=14). Prothoracic tarsal ratio 1.55-2.08 (1.98, n=14), mesothoracic tarsal ratio 2.44-2.87 (2.62, n=14), metathoracic tarsal ratio 2.07-2.50 (2.24, n=14); claws short, equal sized with bifid apices. Wing membrane and veins without macrotrichia; second radial cell 2.20-3.00 (2.60, n=7) x longer than first; wing length 1.02-1.21 (1.12, n=14) mm, width 0.32-0.40 (0.33, n=13) mm; costal ratio 0.68-0.71 (0.69, n=11). Genitalia ( Figs. 12 View Figures 5-12 , 21-23 View Figures 20-27. 20 ): tergite 9 not extending to apex of gonocoxite, distal margin rounded; sternite 9 with curved anterior margin and shallow, rounded posteromedian excavation; cerci divergent, moderately broad, covered with numerous fine and several large setae. Gonocoxite stout, 1.32 x longer than greatest breadth, inner margin with bluntly rounded mesal projection; gonostylus paler, as long as or slightly longer than gonocoxite, proximal portion moderately broad, distal half gently curved, tapering distally to slender pointed apex. Parameres ( Fig. 22 View Figures 20-27. 20 ) separate, slightly divergent distally with curved, heavily sclerotized basal apodeme; distal stem stout, rod-shaped, extending just beyond posterior margin of tergite 9, basal portion moderately sclerotized with ovoid articular pit, distal portion with short, hyaline, pointed, anteriorly directed projection that is adpressed to ventral surface. Aedeagus ( Fig. 23 View Figures 20-27. 20 ) composed of two heavily sclerotized, sinuous sclerites, the tips of which cross each other; with a hyaline L-shaped mesolateral lobe bearing a foot-shaped distolateral projection that is apically pointed.

Distribution. Guadeloupe.

Type material. Holotype male, allotype female labeled “ Guadeloupe, Basse Terre , Trace des Cretes (D- 14), 22-V-2012, R. H. Turnbow, BL Trap ” (deposited in FSCA) . Paratypes, 14 males, 11 females, as follows: same data as holotype, 5 males, 4 females ; same data except 26-V-2012, 1 female (missing abdomen) ; same data except NE Pigeon (16.14404N, 61.74977W), 18-V-2012, 1 male GoogleMaps ; same data except 3.2 km GoogleMaps

E of Mahault , 24-V-2012, 4 females ; same data except Corrosol , 8-IX-2010, MC Thomas & RH Turnbow, Blacklight trap, 4 males, 2 females ; same data except Pigeon , 9-IX-2010, 4 males .

Derivation of specific epithet. We are pleased to name this new species after Michael C. Thomas, one of the collectors of this new species from Guadeloupe and also in recognition of his important contributions to the taxonomy of Coleoptera in the Caribbean Region.

Discussion. Adults of Stilobezzia (A.) thomasi greatly resemble those of S. (A.) tibialis Lane and Forattini and S. (A.) atrichopogon Lane and Forattini, but, in both of these species the scutellum only has 4 large setae. In addition, in S. (A.) atrichopogon the fore and mid legs are yellow and the main stem of the parameres exhibits two distal projections, whereas in S. (A.) tibialis the parameres lack distal hyaline projections, the aedeagal sclerites are more slender and lack a mesodorsal lobe, and the distal half of the gonostylus is straight.

Pinned paratypes of S. (A.) atrichopogon and S. (A.) tibialis were also examined by CGC in the collection of Facultade de Saude Publica, Universidade de Sao Paulo, Brazil.


Departamento de Geologia, Universidad de Chile


Florida State Collection of Arthropods, The Museum of Entomology


Museo de Cipolleti