Madagaster quadricurvipes, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264: 197-199

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Madagaster quadricurvipes

new species

Madagaster quadricurvipes   , new species

Figs. 188 (habitus), 190 (aedeagus), 300 (map)

Type Material. Holotype (male): Fianarantsoa, Andringitra NP: Riambavy R. (female) cascade hygropetric habitat, N -22° 8.761, E:46° 53.4, wet rock surfaces next to high waterfall, elev. 1739 m, 8 v 2006, Bergsten et al. (P39) ( BMNH).  

Differential Diagnosis. Somewhat similar in habitus to M. steineri   ; differing therefrom (males) in larger body size (ca. 3.38 vs. 2.99 mm), having the interrupted areas of the elytral costae larger, and the costae shorter. Differing also in having arcuate meso- and metatibiae ( Figs. 184, 188). The pronotal reliefs of M. quadricurvipes   are more evidently tuberculate, whereas in the compared species the punctures are more evident than are the associated granules. The very complex aedeagi of the two species differ markedly in shapes of the parameres and main piece ( Figs. 186, 190). Females of M. quadricurvipes   are not yet known.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 3.38/1.55; head width 0.84; pronotum 0.74/0.86, PA 0.97, PB 1.04; elytra 2.09/1.55.

Dorsum and venter dark brown. Ocelli light brown.

Antennal club with last antennomere larger than penultimate. Maxillary palpi shorter than antenna, about as long as labrum is wide. Labrum deeply bilobed, pubescent, with longer setae along anterior margin. Labrum originating under slightly overhanging margin of clypeus. Labroclypeal suture very deep. Short, deep sulcus in front of each ocellus. Clypeus very weakly shining, surface slightly uneven and sparsely setose. Frons coarsely punctate, dull, slightly concave between ocelli. Eyes large and protuberant.

Pronotum with two narrowly separated midlongitudinal fovea, anterior three times as long as posterior; each side with two admedian and two sublateral foveae; anterior margin with deep postocular emarginations; lateral margin broadly rounded. Pronotal disc tuberculate, tubercles shining, each with short seta at posterior margin. Lateral foveae with very small and very sparse tubercles, weakly shining.

Elytral suture costate in posterior. First two elytral "interval" costae (from suture) interrupted in two places, third and fourth costa interrupted once. Interrupted areas often longer than costate areas in same line. Between costae usually three rows of setigerous punctures, in places with four rows, interpunctal surfaces sometimes smooth and shining.

Mentum and postmentum sparsely pubescent; Genae microreticulate, dull, deeply concave behind cardo, medial margin of concavity with short carina. Subocular groove for antenna deep and wide. Postocular margin not carinate.

Mesoventrite without tubercle on intercoxal process. Metaventrite densely micropunctulate and with very short and very dense vestiture, except vestiture sparser in deep and wide midlongitudinal depression ( Fig. 188). First two and apparently lateral area of third abdominal ventrites with hydrofuge pubescence, setae much sparser, nonhydrofuge, on other ventrites

Strongly sexually dimorphic (although females are not yet known, the following characters are thought to be male only, based on relationship to M. steineri   : abdominal ventrite four with large tubercle on each side of midline; fifth ventrite with large posteromedian triangular process; sixth retractable (over median portion) within fifth, seventh large and completely exposed; profemur basally on lower margin produced in large pointed process; protibia widened at about midlength; mesotibia very slightly arcuate and apically slightly widened and densely setose; metafemur markedly arcuate in basal 1/3; metatibia arcuate, distal ½ widened and bearing brush of setae.

Etymology. Named in reference to the arcuate meso- and metatibiae of males.