Ochthebius (Asiobates) invictus, Perkins, 2023

Perkins, Philip D., 2023, New Neotropical and Nearctic species of water beetles in the genera Hydraena Kugelann and Ochthebius Leach, a key to North American genera and subgenera of the family, new distribution records, and a synopsis of ecology, behavior and morphology related to aquatic life (Coleoptera: Hydraenidae), Zootaxa 5367 (1), pp. 1-86 : 38-39

Ochthebius (Asiobates) invictus , new species

Figs. 4 (habitus comparison), 22 (habitus and aedeagus)

Type Material. Holotype (male): “ MEXICO: Mexico, NE of Temescaltepec, Rio Verde , 1830 m, 21 iv 2004, coll. William D. Shepard ” ( MCZ).

Differential Diagnosis. The size and habitus of this species are quite similar to those of O. mexicanus Perkins , from which it is externally differentiated by the shape of the anterior margin of pronotum, which is bisinuate, slightly produced in the middle in the new species. Despite the similar habitus of the two species, the aedeagi are quite dissimilar: the terminal piece in O. invictus n. sp. ( Fig. 22 ) has a process, whereas there is no process in O. mexicanus .

Description. Size: holotype (length/width, mm): body (length to elytral apices) 2.23/1.06; head width 0.64; pronotum 0.52/0.94 (width including hyaline margin), PA 0.81, PB 0.56 (PB sclerotized part); elytra 1.31/1.06. Habitus as illustrated ( Fig. 22 ). Form ovate, very convex. Dorsum brown to dark brown; legs and palpi dark brown. Frons and clypeus densely coarsely punctate, effacedly microreticulate; interocular foveae deep and large, width of each equal to distance between them; interocular tuberculi moderately large; basomedial foveae nearly as deep as interocular foveae, slightly smaller. Frontoclypeal suture bisinuate. Clypeus length 1/2 width. Labroclypeal suture straight. Labrum length 1/3 width; microreticulate; median emargination well developed, edge upturned. Maxillary palpus with palpomere 3 moderately wide; palpomere 4 slightly less than 1/2 length of penultimate.

Pronotum with anterior hyaline border moderately wide in front of disc, slightly wider in front of lateral fossulae, then tapered to anterior angles. Lateral hyaline border origin at anterior angles, extended very narrowly along lateral depressions, broad in region of posterior excavation, very narrow around posterior margin. Anterior margin of pronotum produced slightly in middle, bisinuate, with excavation in front of each lateral depression; anterior angles obtuse. Lateral depressions not appearing inflated, very broad, with large very irregular punctures; margins arcuate; posterior extremes excavate; pronotum constricted behind lateral depressions. Lateral fossulae very deeply impressed, with very irregular surface; inner margin abrupt, posterior extreme tapered into lateral hyaline border. Pronotal disc convex, very deeply, coarsely and densely punctate throughout, very narrow interstices effacedly microreticulate; setae absent or very indistinct. Median groove deeply impressed and wide in anterior 0.5, posterior 0.3 deep, smaller than anterior part, round or nearly so; area between anterior and posterior foveae without groove. Anterior foveae very shallow, densely and coarsely punctate. Posterior foveae large, deep, partially confluent with posterior part of median groove.

Elytral disc with broad depression in midregion, humped behind depression, moderately shiny, sides very convex, declivity beginning near posterior 1/3. Six rows of punctures between suture and humeri, punctures very small and indistinct, with rather prominent granule located laterally to each puncture, setae absent or very indistinct. Intervals costate, surface finely irregular, effacedly microreticulate. Explanate margin narrow. Elytral apices narrowly separately rounded. Protarsomeres 1–3 (male) with suction setae.

Venter: Mentum moderately shining, with moderately dense setigerous punctures, setae longer and denser at anterolateral angles. Prosternum hydrofuge pubescent except glabrous shining median carina. Metaventrite pubescent laterally, shining sub-triangular area on disc, glabrous. Abdominal ventrites 1–5 hydrofuge pubescent. Ventrite 6 shining, with sparce, short setae in posterior 1/2. Last tergite slightly acuminated apically.

Distribution. Currently known only from the type locality.

Etymology. Named in reference to the very strong cuticle.

Figures

FIGURE 4. Dorsal habitus of species of Ochthebius.

FIGURE 22. Ochthebius (Asiobates) invictus, new species, holotype habitus and aedeagus.