Madagaster steineri Perkins

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 192-195

Madagaster steineri Perkins

Figs. 184 (habitus), 186 (aedeagus), 215 (antenna, maxillary palpi), 221 (spermatheca), 300 (map)

Madagaster steineri Perkins 1997: 180 .

Type Material. Holotype (male): Antananarivo, Manakambahiny, in seepage over exposed granite cliff face, 18° 55' S, 47° 32' E, 12 i 1990, W. E. Steiner ( USNM). Paratypes: Same data as holotype (5 USNM); Same data, except 15 i 1990, (10 USNM).

Differential Diagnosis. Somewhat similar in habitus to M. quadricurvipes ; differing therefrom (males) in smaller body size (ca. 2.99 vs. 3.38 mm), having the interrupted areas of the elytral costae smaller, and the costae longer. Males differing also in having markedly enlarged maxillary palpi, and differently shaped tibiae ( Figs. 184, 188). The very complex aedeagi of the two species differ markedly in shapes of the parameres and main piece ( Figs. 186, 190). Refer also to the diagnosis of M. cataracta .

Description. Size (holotype, mm, length/width): body (length to elytral apices) 2.99/1.40, head 0.51/0.84, pronotum 0.66/1.19, elytra 2.00/1.40.

Maxillary palpi shorter than antenna, about as long as non-club antennomeres together. Antenna with last antennomere longer than penultimate.

Labrum bilobed, pubescent, with longer setae along anterior margin. Labrum originating at anterior (nonoverhanging) margin of clypeus. Labroclypeal suture very deep, at midline with short longitudinal sulcus that nearly connects with similar sulcus at posterior of head. Short, deep sulcus in front of each ocellus. Clypeus and frons dull, with dual punctation consisting of very dense micropunctulate ground sculpture and less dense, large punctures, setae short.

Pronotum with two narrowly separated midlongitudinal foveae, anterior twice as long as posterior; each side with two admedian and two sublateral foveae; lateral margin rounded. Pronotal disc rugosely punctate.

Elytral suture costate in posterior. First two elytral "interval" costae (from suture) usually interrupted in two places (sometimes only once), third costa interrupted once, fourth costa not interrupted. Areas between carinae with either three or four rows of punctures, each puncture with minute granule and seta at anterior margin.

Mentum and postmentum punctate, microreticulate, and pubescent; Genae microreticulate, dull, deeply concave behind cardo, medial margin of concavity sharply carinate, posterior margin abrupt but not carinate. Subocular groove for antenna deep and wide. Posterior margin of eye not carinate.

Mesoventrite without tubercle on intercoxal process. Metaventrite densely micropunctulate and with very short and very dense vestiture, except vestiture much sparser in deep and wide midlongitudinal depression ( Fig. 184). First two abdominal ventrites with hydrofuge pubescence, setae much sparser, non-hydrofuge, on other ventrites

Strongly sexually dimorphic: in males, maxillary palpomeres three and four very broad, flattened, and microreticulate on ventral surface; abdominal ventrites two to four modified in midline, with midlongitudinal shallow groove, third with two large tubercles at margin of groove; 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 markedly widened and with lower surface slightly concave. Mesotibia apically slightly widened and densely setose. Metafemur markedly arcuate in basal 1/3. Metatibia inner margin at about distal ¼ with row of tubercles, last in row largest.

Abdominal ventrites five and six enlarged in both sexes, in male combined lengths of two to four equal onehalf combined lengths of five and six.

Females smaller than males, ca. 2.50–2.70 mm.