Deltochilum (Deltochilum) eurymedon Genier, new species
Creators: name: Génier, François
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Deltochilum
Deltochilum eurymedon

description: Deltochilum (Deltochilum) eurymedon Génier, new species
(Figs. 13–16)
Type locality. PANAMA: DARIÉN, Estación Ambiental Cana (7°45.32'N, 77°41.07'W), 600–750 m, 5-7.vi.1996, coll. R.S. Anderson, 1996-110 - male holotype (CMNC)
Diagnosis. D. eurymedon is unique in the genus Deltochilum in having the 7th interstrial carina complete and reaching the elytral anterior edge combined with the sharply defined cephalic punctures throughout and from D. rosamariae in having the second interstria distinctly tuberculate apically. The shape of parameres (Figs. 15–16), especially the very long and curved dorsal projections, will also separate D. eurymedon from all other species in the genus.
Description. Holotype male (Fig. 13). Length 30.0 mm, width 21.0 mm. Colour. Black with feeble coppery sheen; antennal club and pubescence fulvous. Head. Clypeus with two sharp, upturned and widely separated teeth anteriorly, anterior margin slightly lobate medially and on each side of teeth. Head dorsal surface with sharply defined punctures throughout, punctures larger and more widely separated on disc; surface between punctures weakly microreticulated anteriorly, microsculpture becoming sharply defined posteriorly giving the surface a silky aspect. Eyes and ocular canthus unmodified. Pronotum. Moderately convex, anterior portion slightly gibbous anteriorly; surface completely punctate, punctures dense and evenly spaced, gradually becoming larger and umbilicate laterally; surface between punctures finely microreticulated on disc and anteriorly, microsculpture becoming strong laterally giving the surface a strong silky sheen on anterior and posterior angles; posterior edge distinctly bisinuate on each side, produced into a small denticle medially. Elytra. broadly arcuate in dorsal view, largest portion just behind mid distance; elytral striae 1–6 fine and distinct from base to elytral apex, with widely spaced oval punctures; interstriae with a network of strong irregular and glossy bulges, base surface with weakly-defined umbilicate punctures; interstria 7 with a strong carina from base to apex; interstria 8 with surface nearly perpendicular to dorsal surface, widest past middle; stria 9 visible and connecting to stria 2 apically; interstriae 8-9 strongly sericeous on most of surface, umbilicate punctures weakly-defined; apical portion with well-defined glossy calluses on interstriae 2–6, calluses gradually becoming longer externally. Thoracic sternites. Mesosternum with anterior margin raised and sinuous medially, remaining surface with coarse umbilicate punctures laterally and a double row of punctures along anterior margin medially. Metasternal median lobe with a more or less rectangular and glossy raised area medially, lateral portions with coarse umbilicate punctures throughout, disc with a more or less oval depression posteriorly, depression lacking tubercle anteriorly. Lateral lobe covered with closely set coarse umbilicate punctures. Legs. Profemur with a dent on anterior edge at about mid-distance to apex, dent almost triangular in shape, with pubescence covering ventral portion; protibia inwardly bent on apical half, with a wide lobate projection before mid-distance on internal edge; mesocoxa with a distinct triangular teeth on posterior edge, with a setal brush on internal side; mesofemur with a ventrally bent triangular process, posterior third surface strongly sericeous, sharply contrasting with glossy anterior surface; metatrochanter with a narrow setal brush ventrally to posterior edge, posterior edge produced into a ventrally bent lobate projection; metafemur strongly arcuate in ventral view, narrowest portion just before mid-distance, posterior surface completely matte and lacking punctures, dorsoposterior edge produced into a lobate projection separated from the trochantofemoral suture by its own width; metatibia sinuous and produced into a wide triangular tooth internally on basal fifth, apex spatulate, internal surface broadly concave. Abdomen. Sternite 3 produced into a strong approximately equilateral triangular process medially, widest portion of process in line with sternite 4. Pygidium approximately as wide as long; surface with transversally oval umbilicate punctures, punctures smaller and more widely separated basally; surface between punctures completely matte; margin very wide apically, internal edge broadly and evenly arcuate. Aedeagus. Parameres nearly symmetrical, with two straight and spiniform processes in lateral view, dorsal process longer, acute and more curved in dorsal view that the ventral one.
Female (Fig. 14). Similar to male, lacking processes or modifications on legs; protibia wider, external teeth larger and obliquely directed. Sternite 3 unmodified medially.
Variation. No variation except for body size and development of secondary sexual characters in males.
Measurements (11 males, 5 females). Body length: male 22.0–30.0 (26.3 ± 2.5), female 26.0–28.5 (27.1 ± 1); body width: male 15.0–21.0 (17.8 ± 1.8), female 16.5–19.0 (17.8±1.2) mm.
Material examined (11 males, 5 females). PANAMA: DARIÉN, Estación Ambiental Cana, elev. 460 m (7°45.5'N, 77°41'W), 3-9.vi.1996, coll. Stockwell - 2 males (including 2 paratypes) (CMNC); same locality, 5- 7.vi.1996, coll. R.S. Anderson (1996-110) - 3 females, 2 males (including holotype, 3 paratypes) (CMNC); same locality, 7-10.vi.1996, coll. R.S. Anderson (1996-117) - 2 females, 7 males (including 9 paratypes) (CMNC).
Etymology. Eurymedon, a Giant of Greek mythology, son of Gaia and brother of Enceladus, relating to the large size and close relationship to D. enceladus.
Natural history. All specimens with data have been collected in human feces baited pitfall traps set up during the afternoon. Current distributional data suggest that it is most likely an endemic of the Eastern Panamanian Mountain Forest. However, the elevation at which specimens were collected (460–700 m) is overlapping the Eastern Panamanian Mountain Forest which ranges from 500–1800 m and the Chocó-Darién Moist Forest which lies at elevations below 500 m. Further collecting will be necessary to settle the issue.
description: Published as part of Génier, François, 2012, A new species and notes on the subgenus Deltochilum (Deltochilum) Eschscholtz, 1822 (Coleoptera: Scarabaeidae: Scarabaeinae: Deltochilini), pp. 25-36 in Zootaxa 3357 on pages 29-30, DOI: 10.5281/zenodo.213648