Bidessodes chlorus, Miller, Kelly B., 2017

Miller, Kelly B., 2017, A review of the Neotropical genus Bidessodes Regimbart, 1895 including description of four new species (Coleoptera, Adephaga, Dytiscidae, Hydroporinae, Bidessini), ZooKeys 658, pp. 9-38 : 15-16

Bidessodes chlorus sp. n. Figs 1-5, 97

Type locality.

Suriname, Sipaliwini District, Camp 1, on Kutari River, 2°10.521'N 56°47.244'W.

Type material.

Holotype in MIZA, male labeled, "SURINAME Sipaliwini District 2°10.521'N 56°47.244'W: 228m Camp 1, on Kutari River leg.A.E.Z.Short, UV-light 19-24.viii.2010; SR10-0819-LT1 2010 CI-RAP Survey/ SEMC0915810 KUNHM- ENT [barcode label]/ HOLOTYPE Bidessodes chlorus Miller, 2016 [red label with black line border]." Paratypes, 6, labeled same as holotype except with different specimen barcode labels and each with “… PARATYPE Bidessodes chlorus Miller, 2016 [blue label with black line border]."

Diagnosis.

This species does not have a carinate prosternum in either male or female. The prosternal process is longitudinally slightly convex and relatively narrow with the lateral margins distinctly convergent to a pointed apex. The male mesotibia is unmodified. The male metatrochanter and metafemur are unmodified (Fig. 5). The male abdominal ventrite VI is unmodified. The male median lobe in lateral aspect is very small basally with the apical portion abruptly bent and broadly expanded with the apex bilobed (Fig. 2). In ventral aspect the median lobe is very broad basally with the lateral margin concave and the apex broad with a deep, narrow medial emargination (Fig. 3). The basal segment of the lateral lobe is elongate and subsinuate (Fig. 4). The apical segment is elongate and obliquely T-shaped with the apical margin broadly emarginate (Fig. 4). Externally, Bidessodes chlorus is similar to many other species of Bidessodes with relatively unmodified ventral surfaces and legs in males or females. The main difference between this species and others is the male genitalia. The shape of the male median lobe and lateral lobes as described above (Figs 2-4) are unlike any other species in the genus. The very broad, angled apical section of the median lobe in lateral aspect (Fig. 2) is particularly unique.

Description.

Measurements. TL = 2.3-2.5 mm, EW = 1.0-1.1 mm, PW = 0.9-1.0 mm, HW = 0.7-0.9 mm, ED = 0.4-0.5 mm, TL/EW = 2.1-2.2, HW/ED = 1.8-1.9. Body shape elongate oval, pronotum widest medially, similar in width to greatest width of elytra, lateral outline discontinuous between pronotum and elytron.

Coloration (Fig. 1). Head and pronotum yellow, posterior margin of pronotum medially brown. Elytron with base color brown to dark brown with diffuse, transverse pale regions anteriorly, medially and at apex (Fig. 1); surface not iridescent. Head appendages, legs and ventral surfaces yellow to yellow-orange.

Sculpture and structure (Fig. 1). Head with dorsal surface smooth and shiny, impunctate. Pronotum (Fig. 1) smooth and shiny with few micropunctures, broadly distributed; lateral margins broadly rounded, pronotum broadest medially, slightly constricted at posterior angles, about same width as greatest width of elytra; basal striae moderately well impressed, extending about 2/5 distance across pronotum. Elytron (Fig. 1) very broadly curved laterally; shiny, finely microreticulate across surface, irregularly and inconsistently micropunctate. Prosternal process elongate triangular, basally broad and posteriorly convergent to sharply pointed apex; surface weakly convex. Metaventrite process anteriorly produced with weak lateral carinae that do not extend posteriorly; surface of metaventrite smooth and shiny, not carinate or otherwise modified. Metacoxa with lateral portions shiny, not punctate; metacoxal lines elongate, subparallel. Abdominal ventrites smooth, impunctate; ventrite VI smooth, evenly convex, apically pointed.

Male genitalia. Median lobe in lateral aspect short and robust, basal portion small, apical portion robust, strongly angulate medially, apically broad and truncate (Fig. 2); median lobe in ventral aspect broad basally, medially constricted and expanded apically with lateral margins each broadly concave, medially deeply and narrowly emarginate, lateral branches apically rounded with small medially-directed point (Fig. 3); lateral lobe in lateral aspect irregular, basal portion elongate, curved and constricted medially along ventral margin, apical portion broad basally, apically broadly and obliquely T-shaped with lateral apices pointed and truncate apex shallowly and irregularly concave (Fig. 4).

Sexual dimorphism. Male pro- and mesotarsomeres I-III broader than in female with extensive ventral adhesive setae. Male and female otherwise similar.

Variation. Specimens vary in the extent and intensity of coloration on the elytral surface, though all specimens have some degree of maculation.

Etymology.

This species is named chlorus , Greek for "pale green" after one of the four horsemen of the apocalypse.

Distribution.

Bidessodes chlorus is known only from southern Suriname (Fig. 97).

Habitat.

The type specimens were collected at a UV light. No other natural history information is known about this species.