Comprehensive Description

provided by Smithsonian Contributions to Zoology
Phanocerus congener Grouvelle

Phanocerus congener Grouvelle, 1898:46.—Zaitzev, 1908:289; 1910:8.—Leng and Mutchler, 1914:423.—Darlington, 1936:73.—Blackwelder, 1944:273.—Hinton, 1971:253.

DIAGNOSIS.—Length, 2.13 to 2.45 mm. Pronotum subquadrate, moderately convex; anterolateral angles broad, explanate. Known only from the Lesser Antilles.

REDESCRIPTION (MALE).—Body Form and Size: Elongate, subparallel, moderately convex. Length, 2.15 mm; greatest width, across humeri, 0.85 mm.

Color: Cuticle reddish black to pale brown; mouthparts, basal antennal segments and legs paler brown. Dorsal surface with partly erect brownish hair-like setae and more dense and finer hair-like setae that are golden in certain lights.

Head: Without distinct impressions. Punctate; punctures contiguous to separated by diameter of puncture. Eyes narrowed posteriorly; lateral and posterior margins around eyes with very long, stout, black setae that curve across eye and generally meet about middle of eye. Clypeus with anterior margin truncate; angle on each side broadly rounded. Labrum with anterior margin broadly, shallowly, arcuately emarginate, and angle on each side broadly rounded; anterior margin, except middle, with a dense fringe of long, golden yellow, hair-like setae; a tuft of longer and denser hair-like setae on each side behind angle. Gula, at anterior margin, as broad as submentum; sides converging and posterior margin about as wide as submentum. Submentum with anterior margin truncate.

Thorax: Pronotum broader than long (0.73 mm : 0.54 mm); broadest at basal two-fifths; base broader than apex; surface similarly but more sparsely punctate than head. Scutellum flat, broader than long; base broadly arcuate and coming to a rounded point posteriorly. Elytron 1.50 mm long and 0.42 mm wide. Elytra between humeri and apical two-fifths nearly parallel; humeri slightly gibbous; each apex slightly rounded and apices conjointly rounded; lateral margins smooth; intervals flat and surface punctate as pronotal disc; striae lightly impressed but narrower and slightly deeper toward apex; discal strial punctures round to subquadrate, separated longitudinally by about a diameter, and – as broad as intervals; punctures becoming slightly finer laterally and much finer toward apex; diameter of punctures on apical fourth about equal to width of adjacent interval. Prosternum moderately short in front of anterior coxae. Metasternum with a shiny, impressed, median, longitudinal line extending entire length.

Abdomen: Apical margin of sterna 5 and 6 broadly rounded.

Genitalia: As illustrated (Figures 41, 42).

FEMALE.—Similar to male externally. Genitalia as illustrated (Figure 43).

VARIATIONS.—Length and width vary; males (n = 8) range in length from 2.18 to 2.30 mm (x = 2.11 mm); females (n = 8) range in length from 2.13 to 2.45 mm (x = 2.32 mm).


Balthazar, windward side, H.H. Smith (BMNH) [holotype, sex undetermined]; Vendome (near), high altitude stream above Vendome, 21 Jul 1973, A.D. Harrison, 2 spms (NMNH).

TRINIDAD: St. George County: Acono River, Maracas Valley, 16 Nov 1989, M. Alkins-Koo, 8 spms (UWI); Arima River, cascade, Sep 1984, V. Jones, 1 spm (UWI); Arima River, cascade, Apr 1985, V. Jones, 1 spm (UWI); Guanapo River, 2 Nov 1989, M. Alkins-Koo, 9 spms (UWI); Marianne Riv., lower stream, 1989, V. Jones, 2 spms (NMNH).

DISTRIBUTION (Figure 50).—Phanocerus congener is known from Grenada, St. Vincent, Tobago, and Trinidad in the Lesser Antilles. The records of the species from St. Vincent and Tobago are from Hinton (1971); we have not seen those specimens but do not question his data.

HABITAT.—The specimens collected from Grenada by A.D. Harrison were obtained from a “high altitude stream above Vendome-shaded torrential stream.”

The specimens collected from Trinidad by Mary Alkins-Koo were found in association with the following genera and species of elmid beetles: Heterelmis simplex codrus Hinton, Hexacylloepus smithi (Grouvelle), Macrelmis clypeatus (Hinton), Microcylloepus carinatus Hinton, and Neoelmis pusio Hinton.

Pharceonus, new genus

DIAGNOSIS.—Length, 3.5 mm or less. Pronotum with a transverse, bisinuate, subbasal impression and a transverse bisinuate impression at the apical third (Figures 4, 55).

ADULT.—Body elongate, subparallel, slightly constricted at midlength, and moderately convex (Figures 52–54). Integument clothed, for the most part, with dense, moderately long, usually recumbent hydrofuge pubescence.

Head partly retracted into pronotum but not beyond the basal portion of the submentum. Mouthparts visible. Maxillary palpus, 4 segmented. Labial palpus, 3 segmented. Antenna, 11 segmented. Clypeus transversely rectangular; frontoclypeal suture deep, extending between bases of antennae; anterolateral angles broadly rounded. Labrum transversely rectangular; anterior margin subtruncate; anterolateral angles broadly rounded.

Pronotum (Figures 4, 55) widest at midlength; anterior margin moderately arcuate over base of head; convex across anterior third, laterally, discally on each side of median impression, and medially behind subbasal impression; a transverse, bisinuate impression at apical third; a sublateral impression on each side extending posteriorly from an anterolateral fovea almost to base; sublateral impressions, turning toward midline at base, uniting basomedially, and extending anteriorly to transverse apical impression; a short longitudinal carina mediad of each subfoveate posterolateral angle. Hypomeron oblique. Scutellum flat and ovoid. Elytron without accessory stria; intervals flat except extreme base of interval 3 slightly raised; humeri swollen. Hind wing (Figure 51) without radial cross vein; without anal cell; anal vein 2 with branches 1 and 2 fused; anal vein 1 short, present only distally and not connected to cubito-anal cross vein; cubito-anal cross vein not joining anal vein 2 to cubitus. Prosternum in front of procoxae about three-fourths length of procoxa, flat, and in same plane as prosternal process. Prosternal process slender; 4 times as long as wide; with low, broad carina on meson; apex acute. Mesosternum with a deep broad depression on midline for reception of prosternal process. Metasternum depressed between mesocoxae; anterior third of disc slightly convex; with narrow, glabrous, longitudinal groove on midline; posterior two-thirds of disc shallowly depressed adjacent to groove. Epipleuron oblique until posterior margin of abdominal sternum 3 then inflexed horizontally.

Abdomen with a longitudinal carina extending from each metacoxal cavity to hind margin of sternum 1. Sterna 1–3 slightly convex in both sexes.

TYPE SPECIES.—Pharceonus volcanus Spangler and Santiago, new species.

ETYMOLOGY.—Pharceonus is an anagram of its sister genus Phanocerus; gender, masculine.
bibliographic citation
Spangler, Paul J. and Santiago-Fragoso, S. 1992. "The Aquatic Beetle Subfamily Larainae (Coleoptera: Elmidae) in Mexico, Central America, and the West Indies." Smithsonian Contributions to Zoology. 1-74. https://doi.org/10.5479/si.00810282.528


provided by Zookeys
This species has previously only been known from the Lesser Antilles, but is actually widespread in Venezuela, found throughout Western Venezuela in the Mérida Andes and the coastal ranges (Fig. 7). The habitat of Phanocerus congener is similar to that of other Phanocerus species, in partially submerged leaf packs and woody debris.
Crystal A. Maier
bibliographic citation
Maier C (2013) A revision of the Larainae (Coleoptera, Elmidae) of Venezuela, with description of nine new species ZooKeys 329: 33–91
Crystal A. Maier
visit source
partner site