Hydraena (Hydraenopsis) scintillasolata, 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 : 26-27

Hydraena (Hydraenopsis) scintillasolata , new species

Figs. 3 (habitus comparison), 14 (habitus and aedeagus)

Type Material. Holotype (male): MEXICO: “MEX: Baja Calif. Sur, Sierra Laguna, La Laguna, 17 air mi. ENE Todos Santos, 6000’, XII-12/18-1979 // under streamside stones & debris // 12– 18.xii. 1979, leg. J. Doyen W. Tschinkel collectors” ( MCZ) . Paratypes: Same data as holotype (13 MCZ) ; Chihuahua: Majaica Rd. 5500’ 30 mi. NW Chihuahua, Chih. MEX. 14–17.IV.61 Howden & Martin (1 male MCZ) .

Differential Diagnosis. This new species is a member of the H. leechi Group (see Perkins 1980: 65), having a large pronotal scintilla, lacking metaventral plaques, and males having brushes of setae on the metatibiae. It will key to H. leechi in Perkins (1980: 66). It is very similar externally to H. leechi , differing in being slightly larger (ca. 1.88 vs. 1.80 mm), and slightly more coarsely densely punctate on the head and pronotum. Dissection and careful examination of the male genitalia will be necessary for reliable determinations ( Fig. 14 ).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.88/0.81; head width 0.45; pronotum 0.47/0.63, PA 0.48, PB 0.55; elytra 1.15/0.81. Habitus as illustrated ( Fig. 14 ). Dorsum with head dark brown, pronotum with dark brown disc surrounded by wide brown margins, elytra dark brown, palpi light brown, tip of last palpomere slightly darker. Dorsum of head and pronotum coarsely very densely punctate, interstices weakly shining; punctures of frons disc and pronotal disc ca. 3xef, interstices narrow walls to 0.5xpd; punctures of clypeus moderately fine, lateral areas microreticulate. Labrum apicomedially excised, free margins weakly upturned. Pronotum with anterior margin weakly emarginate over middle ½, scintilla large; anterolateral, posterolateral and posteromedial pronotal deep; anterior ½ of disc with shallow transverse impression.

Elytra with summit of posterior declivity at or near posterior 1/3; lateral explanate margins wide; on basal 1/3 punctures ca. 1xpd of largest pronotal punctures, punctures becoming gradually smaller toward posterior. Intervals not raised, width narrow walls to ca. 0.5xpd, as are interstices between punctures of a row. Apices in dorsal aspect separately rounded, in posterior aspect margins forming deep angle with one another.

Venter: Mentum concave in basal ½; mentum and postmentum very finely densely micropunctulate, dull. Genae raised, weakly shining, without posterior ridge. P1 laminate; median carina sinuate in profile. P2 l/w ca. 4/1, sides parallel, apex blunt, apex raised above mesoventral intercoxal process. Plaques absent; median depression of metaventrite deep. AIS width at straight posterior margin ca. 3x P2. Protibia slender, very slightly arcuate. Mesotibia straight. Metatibia arcuate, inner margin with small brush of setae subapically. Abdominal apex symmetrical; last tergite with shallow apicomedian emargination.

Distribution. Currently known from Baja California Sur and Chihuahua, Mexico.

Etymology. Named in reference to the large pronotal scintilla and the geographical distribution, in sunny, extremely hot regions.

Figures

FIGURE 3. Dorsal habitus of Hydraena species, H. leechi Group.

FIGURE 14. Hydraena (Hydraenopsis) scintillasolata new species, holotype habitus and aedeagus.