Acoma pararobusta Evans & Smith, 2020

Evans, Arthur V. & Smith, Andrew B. T., 2020, On the tribal classification of the Nearctic Melolonthinae (Coleoptera: Scarabaeidae), with descriptions of new species of Acoma Casey, 1889, Zootaxa 4748 (1), pp. 51-77 : 61-62

Acoma pararobusta Evans & Smith , new species

Figs. 23–28

urn:lsid:zoobank.org:act:9342C833-0F57-4CCB-9819-C38902BAE444

Type material. Holotype male (CASTYPE 19749), labeled “ MEX.: Baja Calif. Sur / El Sargento, 29.VII. / 1971. At U.V. light / H.G. Real & R.E. Main // n. sp.? / DET. / A.R. Hardy 1979 // Acoma / n. sp. 3 / det. W.B.Warner 2015 // CASENT / 8424521 // HOLOTYPE / Acoma / pararobusta / Evans & Smith , 2019”.

Paratypes, (2 males): same data as holotype, except no determination labels, CASC database numbers CASENT 8424522–8424523 .

Paratypes are deposited in CASC (1 paratype; CASENT 8424523), CMNC (1 paratype; CASENT 8424522) .

Diagnosis. Rufopiceous or rufobrunneus dorsally; anterior clypeal margin shallowly emarginate or rounded medially; frontoclypeal suture tumid; antennae composed of 9 antennomeres, antennomeres 5–9 lamellate, subequal in length; protibia distinctly tridentate; elytral disc with scattered, pale setae.

Description. Holotype male ( Figs. 23–28 ), length: 9.0 mm, width: 4.0 mm. BODY dark brown, elongate, robust, moderately convex. HEAD ( Fig. 26 ) with narrowly raised transverse impunctate area, frons and base of clypeus deeply and rugosely punctate, reflexed clypeal margins smoother, with deep punctures mostly separated by their own diameters; short and irregular supraorbital carina obsolete at bases of head and clypeus. Clypeus somewhat semicircular, lateral margins narrowly reflexed, apical margin more broadly reflexed and slightly concave. Ocular canthus thick and broadly rounded apically, about one-third length of eye when viewed laterally, densely setose with setae somewhat longer than canthus. PRONOTUM about half length of elytron, as long as wide; disc glabrous with moderately dense punctures usually separated by twice their diameters sometimes briefly confluent on either side of narrow longitudinal impunctate area medially, punctures become denser laterally, even more so anteriorly; anterolateral margins sinuate, abruptly converging anteriorly from middle, posterolateral margins subparallel, shallowly concave medially; lateral and posterior margins with narrow bead, lateral margins distinctly setose with setae long; anterior margin mostly concave between acute and produced anterior angles, slightly protruding medially, with broad bead; posterior angles broadly obtuse. SCUTELLUM broadly elliptical, basal half sparsely and setigerously punctate, setae coarse. ELYTRON shiny and setose, with deep, narrow striae on disc with setigerous punctures bearing recumbent setae becoming short and irregular on declivities. LEGS with tridentate protibia deeply emarginate between apical and middle teeth, shallowly emarginate between middle and basal teeth. PYGIDIUM broadly parabolic, rugosely punctate along sides, and setose with setae long, erect. GENITALIA with parameres symmetrical, slender and slightly sinuate when viewed laterally, with membranous flange extending to apical fourth, and not as long as phallobasis ( Figs. 27–28 ).

Variation. Length: 7.5–9.0 mm, width: 3.2–4.0 mm. Color varies from light to dark brown. Anterior clypeal margin ranges from slightly concave to nearly rounded.

Etymology. This is named in recognition of the similarities with A. robusta Van Dyke, 1928 .

Remarks. Acoma pararobusta new species is distinguished from all other species in the genus by the characters given in the diagnosis. In addition to the tumid frontoclypeal suture, it is distinguished from A. robusta by the coarse, rugose sculpturing on the frons and base of the clypeus, occasional confluent punctures on pronotal disc, and the somewhat semicircular clypeal margin with bases that are more or less continuous with the supraorbital carinae.

Figures

FIGURES 23–28. Acoma pararobusta Evans & Smith, new species, male holotype. 23, Dorsal habitus; 24, oblique habitus; 25, ventral habitus; 26, head; 27, dorsal parameres; 28, lateral genitalia.