Acoma eusexfoliata 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 : 58-59

Acoma eusexfoliata Evans & Smith , new species

Figs. 11–16

urn:lsid:zoobank.org:act:3E6AE0B3-F1E1-4B43-B817-93408AC25611

Type material. Holotype male (CASTYPE 19860), labeled “ MEXICO, Baja Calif. Norte / 2 mi. SW San Francisquito / box canyon with caves BL / VII-26/27-86 R. L. Aalbu // Dr. Alan Hardy / Donation to the / California Academy / of Sciences // CASENT / 8424551 // HOLOTYPE / Acoma / eusexfoliata / Evans & Smith, 2019”.

Diagnosis. Light reddish testaceous dorsally with head and pronotum darker; anterior clypeal margin weakly emarginate and strongly reflexed; antennae composed of 9 antennomeres, antennomere 3 much longer than 1+2 with anterior projection at base, 4–9 lamellate; protibia apparently bidentate; elytral disc with scattered erect setae.

Description. Holotype male ( Figs. 11–16 ), length: 6.0 mm, width: 4.0 mm. BODY somewhat robust, testaceous, with head, pronotum and elytral apices slightly darker. HEAD ( Fig. 14 ) with vertex rugosely punctuate, clypeus shagreened with large shallow punctures separated by their own diameters or more; supraorbital carinae becoming obsolete at bases of head and clypeus. Clypeus subtrapezoidal with lateral margins broadly arcuate and weakly reflexed; anterior margin shallowly concave, not quite truncate, strongly reflexed, and angulate. Ocular canthus about one-quarter of eye length when viewed from side, with scattered pale setae each longer than canthus. PRONOTUM wider than long, broadest before middle, slightly more than one-third length of elytron; disc strongly convex, sparsely and shallowly punctate, with broad impunctate area medially; lateral and posterior margins with bead; anterior margin broadly concave between obtuse anterior angles; anterolateral margins straight and convergent anteriorly, posterolateral margins slightly concave and convergent posteriorly, with posterior angles broadly rounded. SCUTELLUM broadly parabolic, about one-quarter width of elytron, setigerously punctate at base, finely shagreened medially and apically. ELYTRON convex, shiny, finely shagreened, disc punctostriate with punctures becoming confused on apical and lateral declivities, setigerous punctures with short, suberect setae. LEGS with protibial apparently bidentate, basal third tooth barely indicated by weak angulation. PYGIDIUM parabolic, finely shagreened, with scattered setigerous punctures, setae long. GENITALIA with parameres symmetrical, moderately slender and more or less straight when viewed laterally, with membranous flange extending to apical 3/5, and shorter than phallobasis ( Figs. 15–16 ).

Variation. This species is known only from the holotype.

Etymology. This species is named for actually having 6 antennomeres in its antennal club, unlike A. sexfoliata Saylor, 1948 , which has 7 antennomeres.

Remarks. Acoma eusexfoliata new species is distinguished from all other known Acoma species by its antennal configuration. The unique holotype was originally glued by its abdomen to a point. The specimen was placed in hot water and removed from the point and pinned. While removing the abdomen for genitalic dissection, the right protibia was accidentally detached the body at the base of the femur. Rather than gluing the detached appendage back in place, it was affixed intact onto a separate point and pinned below the specimen.

Figures

FIGURES 11–16. Acoma eusexfoliata Evans & Smith, new species, male holotype. 11, Dorsal habitus; 12, oblique habitus; 13, ventral habitus; 14, head; 15, dorsal parameres; 16, lateral genitalia.