Electribius llamae, Gimmel, Matthew L. & Bocakova, Milada, 2015

Gimmel, Matthew L. & Bocakova, Milada, 2015, A new extant species of Electribius Crowson from Honduras (Coleoptera: Elateroidea: Artematopodidae), Zootaxa 3926 (2), pp. 296-300 : 297-298

Electribius llamae new species

Figs. 2–5

Diagnosis. This species is easily distinguished from the other three extant species of Electribius by the lack of a well-demarcated, deep, setose pit below the antennal insertion, and the presence of a small round pore near the posterior angle of the pronotal hypomeron. Additionally, the coloration of this species is distinctive, having an almost totally reddish-testaceous head, prothorax, and appendages contrasting sharply with the nearly black elytra, meso- and metaventrites and abdomen. It may be further distinguished by the small size (2.0 mm or less) and proportionally longer ventrite 5, with ventrites 1–4 only 2.5 times length of ventrite 5, 2.6–2.9 times longer in E. crowsoni and E. similis . The new species can be distinguished from known fossil species by the presence of a short median carina on abdominal ventrite 5 (either absent or complete in other species).

Type material. Holotype, female; abdomen removed and genitalia dissected and placed in DMHF (water- and alcohol-soluble solution) and pinned with specimen, with label data “ HONDURAS: Cortés: \ PN Cusuco 15.48739 \ - 88.23486 ±100 m 1330 m \ 1-VI-2010, beating veg., \ mesophyll forest \ LLAMA 10 Go-C- 06-1-04 // SEMC 0921662 \ KUNHM-ENT // HOLOTYPE \ Electribius \ llamae Gimmel \ des. M. Gimmel [red label]” (1♀). Deposited in SEMC. Paratypes (3). “ HONDURAS: Cortés: \ PN Cusuco 15.48898 \ -88.23707 ± 10m 1260m \ 30- V-3-VI-2010, Malaise \ trap, mesophyll forest \ LLAMA 10 Ma-C- 06-1-01 // SEMC 0923315 \ KUNHM-ENT” (1); “ HONDURAS: Cortés: \ PN Cusuco 15.4857 \ -88.23746 ± 5 m 1210 m \ 30May- 3-VI-2010, Malaise \ trap, mesophyll forest \ LLAMA 10 Ma-C- 06-2-02 // SEMC 1032437 \ KUNHM-ENT” (1); “ HONDURAS: Cortés: \ PN Cusuco 15.48572 \ - 88.23746 ±100 m 1210 m \ 2-VI-2010, beating veg., \ mesophyll forest \ LLAMA 10 Go-C- 06-2-03 // SEMC 1222890 \ KUNHM-ENT” (1♀); all deposited in SEMC.

Description. Female. Length 1.7–2.0 mm. Bicolored, with head, prothorax, antennae, mouthparts and legs (including coxae) reddish-testaceous; elytra, scutellum, meso- and metaventrites and abdominal ventrites dark, nearly black; pronotum medio-basally slightly darkened, especially around basal groove; elytral epipleuron, center of scutellar shield, base of metaventrite and apex and lateral edges of abdomen often slightly lightened ( Figs. 2–3 ). Dorsal surface of body covered with sparse, long, erect to semi-erect, golden setae; ventral surface, legs and antennae with setae slightly denser, shorter and more appressed.

Dorsal surface of head with extremely light and sparse punctation, punctures separated by about twice their diameters; setae on head shorter than on elytra, directed anteriorly. Cavity below antennal insertion for reception of scape broad, shallow, poorly defined, not densely setose. Antennae moniliform, antennomeres 2–10 less than twice as long as wide. Antennomere length ratio 1.35:1.00:1.20:1.15:1.15:1.10:1.15:1.30:1.25:1.25:1.90. Antennomeres 1, 2, and 11 widest at middle, antennomeres 3–10 widest in apical half. Antennomere 11 strongly tapering to acute apex.

Pronotum about 0.59 times as long as wide; with lateral carina minutely crenulate; dorsal punctation more dense and distinct than on head, punctures separated by about their diameters; dorsal setae longer than on head but shorter than on elytra, directed anteriorly. Pronotal hypomeron with small, round, deep pore near posterior corner ( Fig. 4 ). Elytra taken together about 1.7–1.8 times longer than wide and about 3.7 times length of pronotum. Elytral punctation slightly stronger than that on pronotum, in indistinct longitudinal rows, scattered sparse micropunctation present between larger punctures. Elytral margin slightly emarginate near apex at level of sutural groove (and elytral interlocking mechanism on ventral surface of elytron).

Metaventrite with punctation shallow, moderately dense, punctures separated by about 1 to 1.5 times their diameters laterally, sparser medially.

Ratio of length of abdominal ventrites 1–4 to ventrite 5 (measured at midline) about 2.5. Punctation on ventrites weak, moderately sparse; glandular pores apparently absent. Ventrite 5 ( Fig. 5 ) with short, smooth carina in apical 1/4, joined posteriorly with thickened margin of ventrite.

Male. Unknown.

Etymology. The specific epithet “ llamae ” honors the LLAMA (Leaf Litter Arthropods of Mesoamerica) project led by John T. Longino, Robert S. Anderson and Phillip S. Ward, which generated all known specimens. It is a feminine noun in the genitive singular.

Distribution and habitat. Known only from medium elevations (1200–1400 m) of Cusuco National Park, Cortés Province, Honduras ( Fig. 1 ). Two specimens were captured in Malaise traps, while two others were collected by beating vegetation. The four collection localities are within 0.5 km of each other.

Notes. At 2.0 mm or less, these represent the smallest described extant Artematopodidae , though the holotype of E. relictus measures only 2.1 mm. However, Hörnschemeyer (1998) reports seeing two undescribed fossil specimens of Electribius each measuring 1.64 mm in the Polish Academy of Sciences (PAS) collection.

All members of the type series are apparently female. Two are confirmed females based on genitalia dissections. Lawrence (1995) observed in E. crowsoni , the only species known from both sexes, that the two sexes had slightly different antennomere ratios, with antennomeres 3–5 subequal in female, 3 distinctly shorter in male. The two non-dissected members of the type series of E. llamae express no consistent differences in antennal lengths, nor any other observed external character.

The cavity for reception of the antennal scape, below the antennal insertion, is quite different from the previously described species of Electribius . In other species the cavity is small, deep, well demarcated, and lined with dense setae (see Lawrence 1995, Figs. 2–3 therein). In E. llamae the cavity is broad and shallow, and does not contain dense setae. In this respect it is similar to members of Artematopus Perty , Carcinognathus Kirsch and Allopogonia Cockerell. However , in all other genus-level diagnostic character states, E. llamae agrees with other described species of Electribius , implying that the setose cavity must be omitted as a defining characteristic of the genus as used in the keys of Lawrence (1995, 2005). Unfortunately, Hörnschemeyer (1998) did not mention the setose cavities in his description of new fossil species and did not include the character in his diagnostic description of the genus. The apparent plesiomorphic condition suggests that E. llamae is an early-branching member of the genus. However, this hypothesis must await a thorough phylogenetic analysis for testing.

Figures

FIGURE 1. Map of known distribution of extant described species of Electribius. Black circle: E. relictus Arriaga-Varela & Escobar; blue squares: E. crowsoni Lawrence; yellow triangle: E. similis Lawrence; red star: E. llamae new species.

FIGURES 2 – 5. Electribius llamae new species. 2) Paratype, dorsal habitus; 3) paratype, ventral habitus; 4) female holotype, prothorax, ventral view; 5) female holotype, abdominal ventrite 5. Scale bar (for Figs. 2 and 3) = 1.0 mm.