Hydraena ranarilalatianai, Perkins, 2017

Perkins, Philip D., 2017, Hydraenidae of Madagascar (Insecta: Coleoptera), Zootaxa 4342 (1), pp. 1-264 : 141

Hydraena ranarilalatianai , new species

Figs. 127 (habitus), 129 (aedeagus), 289 (map)

Type Material. Holotype (male): Toamasina, Alaotra Mangoro: Analamazoatra SR: close to park entrance: S 18.93573 E 0 48.41741, GB Nets and sieves, stagnant pools in tributary to Analamazoatra river , elev. 930 m, 9 xi 2011, J. Bergsten, R. Bukontaite, T. Ranarilalatiana, & J.H. Randriamihaja ( MAD11-32 ) ( NHRS) . Paratypes (83): Same data as holotype (13); Antananarivo, Andasibe, NP Perinet , Pfütze im Urwald , puddle in jungle, elev. 1250 m, 18° 49' S, 48° 27' E, 5 xii 2000, W. Dolin (MD 4/5) (3 NHRS) ; nr. Anjiro , ex. forest litter, 18° 53' S, 47° 58' E, 21 x 1970, P. Hammond (1 BMNH) ; Perinet , ex. forest litter, 18° 49' S, 48° 26' E, 12 x 1970, P. Hammond (10 BMNH) ; Fianarantsoa, 21.2395S 47.3947E; Matsiara AmbonyRanomafana NP, next to Sahamalaotra trail entrance; forest stream with sandy bottom, elev. 1130 m, 2 xi 2014, P. D. Perkins ( MAD14-04 ) (16 MCZ) ; Toamasina, 18.9355S 48.4166E Alaotra Mangoro Andasibe-Mantadia NP, Analamazoatra 150m E of park entrance, shallow partly dried out forest pond, elev. 930 m, 18° 56' S, 48° 25' E, 27 xi 2014, J. Bergsten, R. Bukontaite, J.H. Randriamihaja, T. Ranarilalatiana & S. Holmgren ( MAD14-14 ) (7 NHRS) ; 18.9357S 48.4 174E Alaotra Mangoro, Andasibe-Mantadia NP, Analamazoatra , 250m E of park entrance, dried up river bed with stagnant pools, elev. 930 m, 18° 56' S, 48° 25' E, 27 xi 2014, J. Bergsten, R. Bukontaite, J.H. Randriamihaja, T. Ranarilalatiana & S. Holmgren ( MAD14-18 ) (4 NHRS) ; Alaotra Mangoro: Analamazoatra SR: close to park entrance: S 18.9355 E 0 48.41656, GB Nets and sieves, dried up forest pond, elev. 970 m, 18° 56' S, 48° 25' E, 8 xi 2011, J. Bergsten, R. Bukontaite, T. Ranarilalatiana, & J.H. Randriamihaja ( MAD11-25 ) (23 NHRS) ; Alaotra Mangoro: Analamazoatra SR: pond 100m S Lac Vert : S 18.93812 E 48.42199, GB Nets & sieves, shallow forest pond, elev. 930 m, 18° 56' S, 48° 25' E, 9 xi 2011, J. Bergsten, R. Bukontaite, T. Ranarilalatiana, & J.H. Randriamihaja ( MAD11-30 ) (6 NHRS) .

Differential Diagnosis. Similar in size (ca. 1.50 vs. 1.55 mm), habitus, and metaventral plaques to H. elementaria ; differing slightly in shape of the pronotum and elytra, and having the elytral serial punctures slightly smaller and closer together. In both species the only pronotal fovea present is PF3. Reliable determinations will require examination of the aedeagi, which do not resemble each other in the least ( Figs. 25, 129).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.50/0.65; head width 0.36; pronotum 0.38/0.47, PA 0.39, PB 0.43; elytra 0.90/0.65.

Dorsum of head with frons and clypeus dark brown to piceous; pronotum with dark brown macula, diffusely margined, borders light brown to testaceous; elytra brown; legs light brown; maxillary palpi testaceous, distal 0.5 of last palpomere slightly darker.

Frons punctures ca. 1–1.5xef, larger and denser near eyes than medially; interstices shining, 0.5–1xpd laterally, 1–4xpd medially. Clypeus very finely sparsely punctate, interstices shining medially, microreticulate laterally. Mentum very sparsely very finely punctulate, strongly shining. Postmentum finely sparsely punctulate, no median depression. Genae raised, shining, without posterior ridge.

Pronotum with lateral margins slightly sinuate, posterior angles nearly right angles; anterior margin straight behind eyes, emarginate in middle; punctures on disc distinctly larger and deeper than those of frons, interstices strongly shining, 1–5xpd, punctures larger and denser at anterior and posterior; PF1 absent; PF2 very shallow; PF3 deep; PF4 absent.

Elytra weakly arcuate laterally; summit of posterior declivity near midlength; lateral explanate margins narrow; serial punctures on disc slightly smaller than largest pronotal punctures. Intervals not raised, strongly shining, ca. 1xpd, as are interstices between punctures of a row. Apices in dorsal aspect conjointly rather sharply rounded, in posterior aspect margins forming very shallow angle with one another.

Ratios of P2 width and plaque shape (P2/w/l/s) ca. 1/0.5/2/2. P1 laminate; median carina sinuate in profile. P2 l/w ca. 3/1, sides slightly converging toward blunt apex, apex raised slightly above metaventral intercoxal process. Plaques narrow, widely separated, converging very slightly anteriorly, very weakly if at all raised, located at sides of median depression. Metaventrite with very short longitudinal ridge on each side, extended posteriorly from margin of each mesocoxal cavity. AIS width at slightly arcuate posterior margin ca. 2x P2. Protibia very slightly arcuate, other tibiae straight, slender. Abdominal apex with very shallow apicomedian notch.

Etymology. Named in honor of Tolotra Ranarilalatiana, a talented Malagasy aquatic entomologist who has collected many new species of Hydraenidae .