Trinomadraena clusa, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 199-200

Trinomadraena clusa , new species

Figs. 191 (habitus), 192 (aedeagus), 219 (antenna, maxillary palpus), 300 (map)

Type Material. Holotype (male): Antsiranana, Mt. d’Ambre , wet moss by petite cascade, 12° 36' S, 49° 10' E, 16 x 1970, P. Hammond ( BMNH).

Differential Diagnosis. Dorsal habitus as in Fig. 191; a moderately sized species with strong elytral costae, the first of which has an interrupted section. Differentiated from all Madagastrini by the hydrofuge pubescence being restricted to the first three ventrites plus the anterior part of the fourth; this vestiture is very dense and very short, perhaps plastron forming. T. clusa also differs from other members of the tribe in having the procoxal cavities closed behind: the prosternal process is slightly widened behind the coxae, and is contacted on each side by the postcoxal processes of the hypomeron. The aedeagus differs in basic plan from that of other Madagastrini ( Fig. 192), as do the antennae and maxillary palpi ( Fig. 219 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.42/1.00; head width 0.60; pronotum 0.60/0.88, PA 0.70, PB 0.67; elytra 1.45/1.00.

Dorsum and venter dark brown to piceous, legs brown, ocelli light brown.

Dorsum of head and pronotum dull, with very small, closely spaced granules, each with a short recumbent seta. Labrum smooth, anterior margin emarginate, setae very sparse. Labrum originating at anterior of non-overhanging margin of clypeus. Labroclypeal suture deep. Small impression in front of each ocellus. Frons with concavity between ocelli. Maxillary palpi shorter than antenna, ca. as long as non-club articles together. Antenna with penultimate antennomere shorter than ultimate.

Pronotum with two narrowly separated midlongitudinal fovea, anterior ca. twice as long as posterior; each side with two admedian and two sublateral foveae; posteroadmedian fovea oblique, deep; sublateral foveae very deep and very large; transverse fovea along base; lateral margin rounded; postocular emarginations shallow.

Elytral suture costate in posterior. Each elytron with four costae; first costa (from suture) interrupted for short distance at ca. middle of length. Each costa with unilinear row of granules. Areas between costae punctate, each puncture with minute setigerous granule at anterior margin. Areas between costae with three irregular rows of punctures, except part of area between costae two and three with four irregular rows. Elytral apices truncate.

Mentum and postmentum micropunctulate, mentum pubescent, especially at anterior; Genae shining, concave behind cardo, with very low posterior ridge. Subocular groove for antenna moderately deep and wide. Posterior margin of eye with low raised rim.

Prosternum without midlongitudinal carina.

Mesoventrite without tubercle on intercoxal process. Metaventrite densely micropunctulate and with very short and very dense vestiture; median depression oval, moderately deep ( Fig. 191). First three abdominal ventrites and anterior of fourth with very dense, short setae (plastron?). Last ventrite oval. Protibia widened in distal 2/3. protrochanter with small, sharply pointed tubercle. Mesotibia inner margin very slightly emarginate. Metafemur rather large. Metatibia slender, bisinuate, inner margin with recumbent setae.

Etymology. Name in reference to the closed procoxal cavities.

Figures

FIGURES 219 – 223. Antennae, maxillary palpi, and spermathecae.