Madagaster cataracta, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 195-196

Madagaster cataracta , new species

Figs. 187 (habitus), 189 (aedeagus), 216 (antenna, maxillary palpus), 300 (map)

Type Material. Holotype (male): Antsiranana, Sava, Marojejy NP, 800m N from Camp I, Humbert waterfall; 14.4333S 49.773E, ex. bedrock pools at side of waterfall, elev . 550 m, 8 xi 2014, P. D. Perkins (MAD14-48) (NHRS). Paratypes (120): Same data as holotype (53 MCZ); same locality, 8–12.xi.2014, J. Bergsten, R. Bukontaite, J.H. Randriamihaja, T. Ranarilalatiana & S. Holmgren (55 NHRS) ; Fianarantsoa, Vatovavy- Fitovinany, Ranomafana NP, Shakaroa waterfall, 2km from park entrance, 21.2631S, 47.4132E, waterfall and hygropetric rock with some dead leaves, 21° 16' S, 47° 25' E, 4 xi 2014, P. D. Perkins ( MAD14-13 ) (8 MCZ) ; Toamasina, 18.8282S 48.4398E Alaotra Mangoro Andasibe-Mantadia NP, Mantadia waterfall Beanamalao, 7km N of park entrance "circuit chute sacre", waterfall with hygropetric rocks, elev . 990 m, 18° 49' S, 48° 26' E, 28 xi 2014, J. Bergsten, R. Bukontaite, J.H. Randriamihaja, T. Ranarilalatiana & S. Holmgren (MAD14-84) (4 NHRS).

Differential Diagnosis. Showing some habitus similarity with M. steineri and M. quadricurvipes , and sharing with them (in males) the dimorphic characters of the abdominal ventrites and the presence of hydrofuge pubescence on only the first two ventrites and the lateral area of the third. Differentiated from those two species by the first elytral costa being interrupted in only one place instead of two, and having differently shaped male meso- and metatibiae ( Figs. 184, 187, 188). Males additionally differing from M. steineri in having simple maxillary palpi. The very complex aedeagi of the three species differ markedly in shapes of the parameres and main piece ( Figs. 186, 189, 190).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 3.00/1.50; head width 0.82; pronotum 0.66/1.22, PA 0.92, PB 0.96; elytra 2.00/1.50. Dorsum and venter black, legs dark brown.

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. Anterior margin of clypeus slightly overhanging labrum. Labroclypeal suture very deep, at midline with shallow short longitudinal sulcus that often 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 ca. twice as long as posterior; each side with two admedian and two sublateral foveae; anterior admedian foveae very large and very deep, separated from anterior sublateral foveae by peaked relief; sublateral foveae large and deep; trnasverse foveae along base; lateral margin rounded. Pronotal disc with small, moderately dense punctures, each puncture with minute granule and very short seta at anterior margin.

Elytral suture slightly raised. Each elytron with four low costae; first costa (from suture) interrupted for short distance at ca. midlength, other costa not interrupted; intercostal areas with small, deep punctures, usually with four irregular rows of punctures, in places with only three rows; each puncture with very small granule and short seta at anterior margin. Elytra very convex posteriorly, apices truncate.

Mentum punctulate, setose, especially anterior and lateral margins. Postmentum punctulate, weakly shining, non-setose. Genae microreticulate, dull, deeply concave behind cardo, posterior margin abrupt but not carinate. Subocular groove for antenna deep and wide. Posterior margin of eye not carinate.

Prosternum without midlongitudinal carina. Mesoventrite without tubercle on intercoxal process. Metaventrite densely micropunctulate and with very short and very dense vestiture, midlongitudinal depression deep ( Fig. 187). First two abdominal ventrites with hydrofuge pubescence, setae much sparser, non-hydrofuge, on other ventrites

Abdominal ventrites three to five modified in midline, third and fourth with large tubercle on each side of midline; fifth ventrite with large posteromedian rectangular process; sixth retractable (over median portion) within fifth, seventh large and completely exposed.

Profemur basally on lower margin with low carina. Protibia straight, gradually slightly widened distally. Mesotibia straight, inner margin apically with brush of setae. Metafemur strong. Metatibia slightly arcuate, inner margin flat and bearing brush of setae over distal 1/2. Females distinctly smaller than males (ca. 2.68–2.85 mm); legs and ventrites non-modified, and elytra not bulbous.

Etymology. Named in reference to the waterfall habitat.