Oocyclus ustulatus, Short & Torres-Gavosto & Hettinger, 2023

Short, Andrew E. Z., Torres-Gavosto, Juan Martin & Hettinger, Ty, 2023, A review of the Oocyclus Sharp of Ecuador with description of 12 new species (Coleoptera: Hydrophilidae: Laccobiini), Zootaxa 5277 (1), pp. 91-112 : 106

Oocyclus ustulatus sp. n.

( Figs. 3B , 6A , 7 )

Type Material. Holotype (male): “[male symbol]” “ECUADOR, Man./ Sto. Domingo de/ los Colorados/ (79 Kms. west)/ 8 May 1975 ”, “Coll’d by/ P. Spangler, / A. Langley &/ J. Cohen ”, “Seepage over/ rock outcrops/ in roadcuts”, “ ECUADOR-PEACE CORPS,/ SMITHSONIAN INSTITUTION/ AQUATIC INSECT SURVEY” ( USNM) . Paratypes (59 exs.): ECUADOR: Manabí Province: same data as holotype (51 exs., USNM, SEMC) ; 26.5 km E. Flavio Alfaro, 380 m, 8.i.1978, leg. P. Spangler, roadside seep (8 exs., USNM) .

Diagnosis. Larger species. Posterolateral corners of pronotum spinose. Prosternal carinae set with two spines anteriorly. Elytra with first row of systematic punctures forming a dense, continuous row bearing erect setae. Elytral margins slightly explanate, without a fringe of long setae. Abdominal ventrites uniformly pale.

This is the largest known species in Ecuador. It can be distinguished from other larger Ecuadorian species by the combination of the spinose posterolateral corners of the pronotum (angulate in O. radiatus ) and the pale abdominal venter (dark brown in O. pakcha ).

Description. Size and Form. Length = 5.2–6.5 mm. Broadly oval, slightly convex. Color. Dorsum of head, pronotum, and elytra black, and usually covered with faint green or brown maculate patches. Anterolateral margins of pronotum with distinct large white patch, slightly less than half the length of the margin. Elytra with a layer of dull bronze maculae which often appear faint and with defuse borders. Maxillary palps yellow, with apical palpomere slightly darkened at apex. Labial palps yellow. Mentum dark brown, similar in color to the venter of the head, stipes reddish brown. Legs, epipleura, prosternum dark brown. Lateral edges of metaventrite lighter in comparison to mesal portion. Abdominal ventrites very pale light brown to yellow. Head. Ground punctation on labrum, clypeus and frons moderately coarse, distance between punctures 0.5–1.0× the width of one puncture. Systematic punctures on labrum consisting of several indistinct punctures. Frons with an irregular row of systematic punctures mesad of each eye, bearing fine setae. Maxillary palps short, subequal in length to width of the mentum; segment 2 slightly bulbous, apical segment slightly longer than penultimate. Labial palps less than half as long as width of mentum; with a clump of long setae on second segment. Mentum quadrate, anterior margin slightly convex but not distinctly depressed, bearing scattered punctures. Thorax. Ground punctation on pronotum and elytra composed of moderate fine, evenly distributed punctures. Pronotal systematic punctures with short fine setae, distinctly larger than ground punctures, anterior and posterior series each forming an irregular field. Lateral margins of pronotum with a sparse row of setiferous punctures; with punctures almost appearing absent, and bearing a very fine, short seta which is almost not noticed. Posterolateral corners of pronotum strongly spinose and directed posteriorly. Elytra with five rows of systematic punctures: the first row is represented as a grove with a dense, continuous row of erect setae, giving a “Mohawk” like appearance. Rows 2 and 3 represented by a nearly regular series of coarse punctures bearing slightly shorter setae than row 1. Punctures in rows 4 and 5 similar to 2 and 3 but irregular in distribution. Prosternum with raised median carina; with two spines at anterior margin of carina. Elevated process of the mesoventrite 3x longer than wide, set with 7–8 thickened, coarse spines. Metaventrite with oval glabrous area posteromedially, twice as long as wide, length of glabrous area approximately half the length of metaventrite. Procoxae densely covered with coarse, thickened spine-like setae. Protibiae with 10–12 spines on dorsal face. Abdomen. Ventrites covered with fine setae, the longest setae shorter than the longest setae surrounding the glabrous area of the metaventrite. Aedeagus as in Figure 6A .

Distribution. Known only from a pair of localities in Manabí Province ( Fig. 7 ).

Etymology. Ustulatus, meaning “scorched or browned” in reference to the brown iridescent maculae that are common on the elytra.

Figures

FIGURE 3. Dorsal, ventral and lateral habitus views of Oocyclus species. (A) radiatus sp. n. (B) ustulatus sp. n.

FIGURE 6. Aedeagi of Oocyclus species in Ecuador with angulate or spinose posterolateral corners of the pronotum. (A) ustulatus sp. n. (B) radiatus sp. n. (C) pakcha sp. n. (D) sumak sp. n. (E) ankas sp. n. (F) lepidus sp. n. (G) bellus sp. n. (H) zamora sp. n. (I) specimen of the morgani/trujillo species group (J) specimen of the morgani/trujillo species group.

FIGURE 7. Distribution of Oocyclus spp. in Ecuador.