Bidessodes erythros, 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 : 16-18

Bidessodes erythros sp. n. Figs 6-10, 97

Type locality.

Guyana, Region 8, Konawaruk River, Basecamp (blackwater camp), 5°03.884'N 59°12.838'W.

Type material.

Holotype in MIZA, male labeled, "GUYANA:Region 8 5°03.884'N 59°12.838'W, 75 m Konawaruk River, Basecamp (blackwater camp): Blackwater crk along margin, with leaf litter leg. Salisbury & La Cruz 10.ix.2014: GY14-0910-02/ SEMC1428326 [barcode label]/ HOLOTYPE Bidessodes erythros Miller, 2016 [red label with black line border]." Paratypes, 15, labeled same as holotype except with different specimen barcode labels and each with “… PARATYPE Bidessodes erythros 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 broadly triangular, slightly convex and apically acuminate. The male mesotibia is unmodified. The male metatrochanter and metafemur are unmodified (Fig. 10) and the male last abdominal ventrite is unmodified. The male median lobe in lateral aspect is broadly lobate basally with the apical portion long, sublinear, moderately broad with somewhat undulate dorsal and ventral margins and of somewhat even width to a rounded apex (Fig. 7). In ventral aspect the median lobe is moderately broad and similar in width to the apex which is divided into two long rami separated by a narrow, deep medial emargination, with the apex of each ramus narrowed to a point (Fig. 8). The basal segment of the lateral lobe is elongate and irregularly shaped (Fig. 9). The apical segment is small with the apex characterized by an anteriorly directed spinous process on the dorsal margin (Fig. 9). Externally, Bidessodes erythros 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 as described above. The male median lobe and lateral lobes (Figs 7-9) are unlike any other species in the genus.

Description.

Measurements. TL = 2.3-2.4 mm, EW = 1.2-1.3 mm, PW = 1.0-1.1 mm, HW = 0.7-0.9 mm, ED = 0.4-0.5 mm, TL/EW = 2.1-2.3, HW/ED = 1.7-1.8. Body shape elongate oval, pronotum widest medially, width less than greatest width of elytra, lateral outline slightly discontinuous between pronotum and elytron, posteriorly somewhat attenuate.

Coloration (Fig. 6). Head and pronotum yellow-orange, posterior margin of pronotum medially narrowly brown. Elytron with base color dark brown with weakly differentiated, diffuse, transverse pale fasciae anteriorly, medially and at apex, anterior and medial pale regions meeting in longitudinal areas medially (Fig. 6); surface not iridescent. Head appendages, legs and ventral surfaces yellow to yellow-orange.

Sculpture and structure (Fig. 6). Head with dorsal surface smooth and shiny, with extremely fine micropunctures, broadly dispersed. Pronotum (Fig. 6) smooth and shiny with broadly dispersed micropunctures; lateral margins broadly rounded, pronotum broadest medially, slightly constricted at posterior angles, somewhat less in width than greatest width of elytra; basal striae moderately well impressed, extending about 2/5 distance across pronotum. Elytron (Fig. 6) very broadly curved laterally; shiny, finely microreticulate across surface, distinctly punctate. Prosternal process basally broad and posteriorly slightly convergent to broadly pointed apex, lateral margins somewhat straight and convergent; surface approximately flat. 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, apically distinctly convergent; metatrochanter and metafemur relatively unmodified. Abdominal ventrites smooth, impunctate; ventrite VI smooth, evenly convex, apically broadly pointed.

Male genitalia. Median lobe in lateral aspect with elongate, oval basal part, apical portion nearly straight, robust, with lateral margins subparallel to rounded apex (Fig. 7); median lobe in ventral aspect broad, lateral margins weakly sinuate, similar in width throughout, apex bifid, each branch apically broadly pointed and slightly curved inward, emargination V-shaped (Fig. 8); lateral lobe in lateral aspect with basal segment elongate, subtriangular with distict apicoventral lobe at base of apical segment; apical segment short and small, apically with truncate and laterally toothed apex, with large, basally-directed tooth on dorsal margin (Fig. 9).

Sexual dimorphism. Male pro- and mesotarsomes I-III broader than in female and with extensive ventral adhesive setae. Otherwise males and females similar.

Variation. Specimens are relatively consistent in color pattern and other features.

Etymology.

This species is named erythros , Greek for “red” after one of the four horsemen of the apocalypse.

Distribution.

This species is known only from central Guyana (Fig. 97).

Habitat.

The type series was collected from a leaf litter area along the margins of a blackwater creek.