Enkyosoma rockwelli, Caterino, Michael S. & Tishechkin, Alexey K., 2014

Caterino, Michael S. & Tishechkin, Alexey K., 2014, New genera and species of Neotropical Exosternini (Coleoptera, Histeridae), ZooKeys 381, pp. 11-78 : 22-23

Enkyosoma rockwelli sp. n. Figs 5, 6, Map 1

Type locality.

COSTA RICA: Puntarenas, Monteverde [10.3194°N, 84.8158°W].

Type material.

Holotype male: "COSTA RICA:PUNTARENAS, Monteverde, Estacion Biologica Monteverde 10°19'10"N, 84°48'57"W, 1730m, 12.VI.2001 R.Anderson, montane forest litter, 2001-107H" / "Caterino/Tishechkin Exosternini Voucher EXO-00175" (CMNC).

Description.

Size range: Length 3.0 mm; width 2.7 mm; Body: body elongate ovoid, widest behind middle, subdepressed, dorsally somewhat flattened, more convex ventrally, dark rufescent, glabrous, with conspicuous ground punctation throughout, lacking secondary punctation, and almost entirely lacking typical striae. Head: frons elongate, largely coplanar with vertex, weakly depressed at middle; frontal and supraorbital striae absent; epistoma wide, somewhat deflexed, weakly emarginate apically; labrum large, about one-third as long as wide, apical margin deeply emarginate, lateral margins with conspicuous setal fringe; mandibles with short incisor edges, left bearing prominent basal tooth, right mandible with weaker basal tooth; submentum wide, slightly depressed relative to surrounding genae, anterior margin weakly outwardly arcuate; mentum trapezoidal, narrowed anteriorly, apical margin more or less entire; labial palps three segmented, basal segment short, penultimate and ultimate palopmeres elongate; submentum and mentum bearing numerous elongate setae; maxillary cardo shining, glabrous, stipes microsculptured and with numerous long setae; maxillary palp four segmented, rather stout; antennal scape elongate, not markedly widened apically, curving posteroventrad beneath somewhat reduced compound eye; funicle about as long as scape, weakly widened distally, the 8th antennomere cupuliform, no shorter than preceding antennomeres; antennal club elongate oval, completely tomentose, with two nearly complete setose annuli more distinctly interrupted on dorsal surface, only slightly curved basad at middle. Pronotum: pronotum weakly convex, sides faintly arcuate from base to apices; prescutellar impression absent, though fine prescutellar fovea may be present; pronotal disk with three median gland openings on each side, one in anterior angles, close to corner, one behind eye about one funicle width behind anterior margin, one directly posterad this one, just behind pronotal midpoint; three distinct gland openings also present along lateral pronotal margin; marginal stria complete along lateral and anterior margins; fragments of lateral submarginal stria visible near anterior corners. Elytra: elytra with few striae extremely fine, inconspicuous; epipleuron with single complete marginal stria and fragments of additional epipleural striae detectable, oblique humeral stria visible near base, 1st dorsal stria finely impressed in apical two-thirds, 2nd stria visible in basal half, slightly abbreviated from base, 3rd stria present in basal third, 4th, 5th and sutural striae entirely absent; elytral disk with very fine granular microsculpture faintly impressed toward apices. Prosternum: prosternal keel depressed, rather broad, produced at base, lacking striae; prosternal lobe about three-fourths length of keel, deflexed, lacking marginal stria; both prosternal keel and lobe rather densely microsculptured. Mesoventrite: mesoventrite broad, subquadrate, anterior margin emarginate, marginal stria faintly impressed. Metaventrite: metaventrite strongly convex posteriorly, posterior margin arcuate; mesometaventral, postcoxal and inner lateral metaventral striae absent, metaventral disk smooth at middle, more distinctly microsculptured at sides. Abdomen: abdominal ventrites 1-4 lacking striae, more or less distinctly microsculptured throughout; propygidium short, transverse, with single gland openings in anterolateral corners; pygidium large, apically rounded; propygidium and pygidium with very fine ground punctation and transverse waves of microsculpture. Legs: each trochanter with 2-3 short apical setae; femora moderately broad, slightly flattened; protibia subtriangular, with outer edge weakly outwardly rounded, not distinctly toothed, but set with about 9 distinct marginal spines; two small protibial spurs present; all tarsi rather long and curving, with numerous ventral spines, those of protarsus (of male only?) strongly spatulate; mesotibia moderately expanded toward apex, metatibia much less so, both with nearly complete series of marginal spines. Male genitalia (Fig. 6): Paired accessory sclerites present; T8 with broad basal and narrower apical emarginations, line of basal membrane attachment complete distad basal emargination, ventral apodemes well developed, narrowing ventrally, slightly separated along midline; S8 with halves approximate at base, apical guides widening from base to apex, apices narrowly rounded, bearing only very fine, inconspicuous setae; T9 with base of dorsal flaps rather protuberant above proximal apodemes, ventrolateral apodemes well developed, T9 apices narrow, convergent subacute; T10 elongate, completely divided; S9 with sides subparallel in basal half, narrowest distad midpoint, head broad, subquadrate apically, with complete apical flange, apex not emarginate; tegmen narrow and elongate, sides parallel in basal half, narrowed to thin, ventrally curved apex, median foramen basad apical narrowing, ventral surface with basal tooth formed by thin median keel; basal piece nearly one-half tegmen length; median lobe about one-third tegmen length, proximal arms thinned basally. Female: not known.

Remarks.

This species is only known from the type specimen.

Etymology.

We name this species for Mr. Marvin Rockwell, one of the original Quaker founders of the Costa Rican community of Monteverde, who has helped many visitors (the senior author included) better appreciate the biodiversity of Costa Rica.