Oocyclus muscus, Short, A. E. Z. & Perkins, P. D., 2004

Short, A. E. Z. & Perkins, P. D., 2004, A revision of Oocyclus Sharp of Mexico and Central America (Coleoptera: Hydrophilidae), Zootaxa 783, pp. 1-45 : 15-16

Oocyclus muscus n. sp.

( Figs. 10 , 22 )

Type Locality. 10.1 km after the private gate, Tapantí National Park, Cartago Province, Costa Rica, 9°41.459’N, 83°45.699’W, 1650m elevation ( Fig. 28 ).

Type material. Holotype. Male. “ COSTA RICA: Cartago Prov./ Tapanti Nat. Park: 7.I.2004 / 10.1 km after Gate; 1650m elev/ A.E.Z.Short & D.J.Lebbin/ AS­04­004; waterfall/seep”, “ HOLOTYPE / Oocyclus / muscus / Short & Perkins” ( INBIO). Paratype. Same data as type (1 AEZS).

Differential Diagnosis. Most similar to O. maculatus , but separated from that species by the mentum and stipes being as dark as the venter of the head.

Description. Size and Form. Length=2.9–3.3. EL/EW=1.11. Oval, slightly to moderately convex. Elytra slightly longer than wide. Color. Dorsum black, with green iridescence on head, pronotum and broad lateral margins of elytra; elytral disc black, without blue or green spots. Maxillary and labial palpi yellow. Mentum and stipes yellow to light brown, lighter than venter of head. Anterolateral corners of pronotum with pale spot. Maxillary palpi yellow, with tip of apical segment slightly darkened. Labial palpi yellow. Mentum and stipes dark brown to black, same color as venter of head. Anterolateral corners of pronotum with pale spot. Sternum and ventrites dark brown to black. Legs yellow, with femora slightly darkened basally and along anterior edge. Head. Punctation on frons, clypeus and labrum moderately fine; distance between punctures 2– 3 x width of one puncture, slightly denser anteriorly. Scape subequal in length as segments 2–5, segment 2 subequal or longer in length than segments 3–5, segments 3 and 4 subequal in length, apical segment slightly longer than penultimate segment. Maxillary palpi ¾ width of labrum; segments 2 and 3 subequal with apical segment slightly longer. Labial palpi subequal to length of mentum; apical two segments subequal in length. Labrum with 2–3 setiferous systematic punctures centrally. Clypeus without detectable systematic punctures. Frons with irregular row of systematic punctures mesad of each eye. Mentum quadrate, anterior margin slightly convex; anterior half with several setiferous punctures. Thorax. Dorsal punctation of pronotum moderately fine, slightly more impressed on elytra; uniform in size; distance between punctures 2– 3 x width of one puncture. Posterolateral corners of pronotum rounded. Lateral margin of pronotum with row of setiferous punctures; anterior and posterior series of setiferous systematic punctures moderately distinct, slightly larger then general punctation; setae recumbent. Sutural row of punctures on elytra extremely fine, irregular; denser on anterior half. Rows of elytral punctures bearing recumbent to suberect setae; slightly larger than surrounding punctures but rows irregular and diffuse, largely obscured by surrounding punctures. Elytral punctation. Lateral margin of elytra with row of setiferous punctures, more dense in posterior half. Prosternum carinate medially, with two weak spines anteromedially which are as long or slightly longer than narrowest width of prosternum. Mesosternal process about as long as wide, with 4–5 distinct spines positioned toward apex. Metasternum with oval glabrous area posteromedially, as long or slightly longer than wide; less than half the total length of metasternum. Procoxae densely pubescent, with a few scattered spines or thickened setae. Protibia with 5–7 spines on dorsal face. Protarsal segments 1–4 small, subequal in length; segment 5 as long as segments 1–4. Hind femora glabrous. Abdomen. Ventrites sparsely pubescent; setae slightly erect to decumbent; as long or longer as longest setae around margin of metasternal glabrous area. Fifth exposed ventrite entire. Area between setiferous punctures rugose on posterior half of fifth visible ventrite. Aedeagus ( Fig. 22 ) with parameres very narrow; dorsal and ventral sides of similar width. Tip of median lobe bifid, not reaching apex of parameres. Basal piece distinctly narrowed and rounded basally.

Distribution. Costa Rica. Known only from the type locality.

Etymology. Muscus , L., meaning moss. The type series was collected in the wet moss adjacent to a waterfall. “ Muscus ” is used here as a noun in apposition.

Figures

FIGURE 10. Oocyclus muscus n. sp. holotype. Dorsal and lateral habitus.

FIGURES 20 – 23. Oocyclus aedeagi, dorsal views. Scale bars = 0.2 mm. – 20. O. maculatus Sharp (holotype). – 21. O. maculatus Sharp (specimen from Panama). – 22. O. muscus n. sp. (holotype). – 23. O. ornatus n. sp. (holotype).

FIGURES 28 – 29. Habitat of Oocyclus species. Photos by A. E. Z. Short. – 28. Type locality & habitat of O. muscus n. sp., Costa Rica, Cartago Province, Tapantí National Park, 6 January 2004. – 29. Type locality & habitat of O. tapanti n. sp. and collecting locality for O. maculatus Sharp & O. ornatus n. sp., Costa Rica, Tapantí National Park, 8 January 2004.