Hydroscapha perijaensis, Hall, Eugene & Short, Andrew E. Z., 2010

Hall, Eugene & Short, Andrew E. Z., 2010, A new species of Hydroscapha LeConte from northwestern Venezuela (Coleoptera: Myxophaga: Hydroscaphidae), Zootaxa 2358, pp. 49-56 : 50-54

Hydroscapha perijaensis sp. n.

( Figs 1–5 )

Type material. Holotype: 3: “ VENEZUELA: Zulia State / Perija National Park [at Toromo]; 395 m / 10º 2.962' N, 72º 42.615' W / 23.ix.2007; leg. A.E.Z. Short / AS-07-023”. Deposited in the Museo del Instituto de Zoología Agrícola ( MIZA), Universidad Central de Venezuela (Maracay, Venezuela). Allotype: Ƥ, (same data as holotype; MIZA). Paratypes (142 exs.): same data as holotype (35 exs.); same locality but 28.i.2009, VZ 09012802 A (72 exs.). VENEZUELA: Zulia State, Perija National Park, 435 m, 28.i.2009, 10º 3.058’N, 72º 42.974’W, leg. A. Short, M. Garcia, & J. Camacho, stream & seep, VZ 09012801 B (35 exs.) In addition to MIZA, paratypes will be distributed in the following institutions: Division of Entomology, University of Kansas (Lawrence, KS, USA), Department of Entomology, University of Arizona (Tucson AZ, USA), W. Eugene Hall Collection (Tucson, AZ, USA), Museo de Artrópodos, Universidad del Zulia (Maracaibo, Venezuela), United States National Museum of Natural History (Washington DC, USA), Vienna Natural History Museum (Vienna, Austria), Czech National Museum (Prague, Czech Republic) and the Field Museum of Natural History (Chicago, IL, USA).

Description. Body of adults fusiform, elongate, somewhat depressed ( Figs 1 A–1C); length 1.15–1.17 mm; color generally light brown to dark brown; pubescence golden to light yellow.

Head. Moderate, wider than long ( Fig. 3 A), widest behind eyes, prognathus, anteriorly arcuate with pronounced frontal ridge; surface with moderately shallow punctures. Antennae sub-clavate, cylindrical ( Fig. 3 B), extended beyond anterolateral margins of head, possessing 8 antennomeres, segment VIII enlarged and elongate, longer than antennomeres V-VII combined, antennae inserted beneath the frontal ridge, between eyes and base of mandibles. Labrum well-developed, fused to clypeus, apically arcuate. Mandibles small, apices blunt, bidentate apically, Maxillary palpi prominent, possessing four palpomeres, apical one small, no longer than wide, apex acute; penultimate enlarged and three times as long as apical. Labial palpi possessing three palpomeres, small and obscure. Gular sutures present, widely separated then converging anteriorly. Tentorium well-developed. Eyes small, oval, widely separated, not protuberant, interfacetal setae present.

Pronotum. Broader than head ( Figs 1 A–1B, 2A), widest at hind angles, nearly as wide as elytra; anterior margin excavated to receive head; lateral margins arcuate, sides deeply explanate, posterior margin arcuate, distance between hind angles twice the length of pronotum anterior to hind margins medially. Prosternum short, spinasternum depressed, obscure. Procoxal cavities opened posteriorly, procoxae conical, prominent.

Mesosternum. Short, mesocoxal cavities widely separated, mesocoxae small, ovate; mesosternal disc wider than long, separating mesocoxae ( Figs. 1 B, 3C).

Metaventrite long ( Figs 1 B, 3C), widest at hind angles, metacoxal cavities widely separated, metacoxae transverse, posteriorly enlarged and forming a coxal plate partially covering hind femora. Trochanters small, triangular. Femora and tibiae normal.

Scutellum. Acute posteriorly, wider than long.

Elytra. Truncate, exposing abdominal tergites, elytron longer (0.60 mm) than wide (0.37 mm), widest at anterior half; setae moderately flat, setal length two-three times distance between elytral punctures ( Figs 1 A, 2B–2C).

Hind wings. Present, fringe of setae along margin of wing membrane, setae longest (0.22 mm) along distal margin of wing, width of wing membrane widest (0.41 mm) distally.

Tarsi. 3–3–3; claws moderate, wider at base than distally, males possessing an oblong disc at base of protarsal claws; meso- and metatarsal claws of male subequal, the outer claw possessing an invagination medially, anterioly to base of claw.

Abdomen. Narrowed posteriorly, possessing a dense mat of recumbent setae on tergite IV, forming a plastron beneath elytra; tergite VIII of female rounded apically ( Fig. 5 A), terminal segments tapered posteriorly, acute, bifid ( Fig. 5 C); abdominal sternite VIII of male possessing two widely separated, moderately acute lobes along posterior margin ( Fig. 5 B), sternite IX not tapered, hind margin arcuate medially with hind angles widely separated ( Fig. 5 D). Aedeagus 0.30 mm long, acute posteriorly, widest anteriorly at basal bulb ( Fig. 5 E).

Distribution. Currently known from two sites located less than 1 km apart in the foothills of the Serrania de Perija near Toromo, along the northwestern border of Venezuela.

Etymology. The specific epithet is derived from the type locality.

Bionomics. The species was first encountered in the wet season (September) living in a seepage flowing over exposed, sunlit rock adjacent to a small stream ( Fig. 6 ). The same site was visited in the early dry season (January) at which time the seepages were completely dry. However, the small stream was now reduced to a small trickle with areas mimicking the now-dry side seepage in which many specimens of the new species were found, particularly in clumps of moss. The species was also found in a similar exposed seepage habitat in a second stream less than 1 km west of the first site. No specimens were found in other co-occurring habitats such as sandy stream margins or leaf packs. Over the last several years a number of Venezuelan rock seepage habitats have been examined by AEZS and several Venezuelan colleagues including sites in the primary Venezuelan Andes, the Cordillera de la Costa, and in Guiana Shield-associated outcrops. Despite these efforts no other Hydroscapha specimens have yet been found, suggesting the genus is not widespread or at least highly localized in distribution.

Numerous females were found to contain one to two nearly-fully developed eggs in specimens collected in the wet season (dry season specimens were not examined for this purpose).

Figures

FIGURE 1. Habitus of H. perijaensis sp. n.. A) dorsal; B) ventral; C) lateral. Scale bar = 0.5 mm.

FIGURE 2. H. perijaensis sp. n. A) head and pronotum (dorsal); B) elytron (dorsal); C) elytron (ventral).

FIGURE 3. H. perijaensis sp. n. A) head (ventral); B) antenna; C) mesosternum and metaventrite (ventral).

FIGURE 4. H. perijaensis sp. n. A) terminal abdominal segments; female; B) terminal abdominal segments, male.

FIGURE 5. H. perijaensis sp. n. A) tergite VIII, female; B) sternite VIII, male; C) terminal abdominal segments, female; D) terminal abdominal segments, male; E) aedeagus (lateral).

FIGURE 6. Type locality of H. perijaensis sp. n., Venezuela: Zulia State, edge of Perija National Park at Toromo. A) Seepage habitat at type locality on 23 September 2007 (wet season); B) overview of the type locality on 28 January 2009 (dry season), and C) 23 September 2007.