Acoma quadrilaminata, Warner, 2011

Warner, William B., 2011, Four new species of Acoma Casey, with a key to species in the genus (Coleoptera: Scarabaeidae: Melolonthinae), Insecta Mundi 2011 (172), pp. 1-17 : 4-5

Acoma quadrilaminata new species

Figures 10-13

Type Material. Holotype male ( UNAM): “ MEX: Baja Calif. Norte, 3 mi. N Las Arrastras , VII-7-1973, Fisher & Westcott.”

Paratypes, (5 males) with data same as holotype.

Paratypes are deposited at WBWC, RLWE, CASC.

Diagnosis. Medium brown, vestiture light colored and contrasting with cuticle color, pronotum glabrous except for marginal fimbriae; elytral disc hairy; clypeal disc nearly impunctate; antenna 9-segmented, with 4-segmented club, all club lamellae of equal size; anterior tibia tridentate; paramera as in Figure 12 .

Description. Holotype male, length: 6.9 mm, width: 3.1 mm, widest at about middle of elytra.

BODY medium brown, shiny, hairs lighter colored and contrasting with ground color. HEAD with front and clypeal base scabrously, subreticulately punctate-rugose, weakly convex, more noticeably so on frontoclypeal transition; clypeus broadly parabolic, apically weakly emarginate, obtusely subdentate at each lateral terminus of emargination, margins moderately reflexed, only little more strongly so apically, disc concave, deeply punctate, punctures mostly separated by less than their own diameters; antenna 9- segmented, club four segmented, segment 5 (basal to club) unusually elongate, in form of flattened cylin- der and about as long as segments 2-4 combined. PRONOTUM glabrous except for marginal bead, length about 0.4 times elytral length, widest at about middle; lateral margins straight in posterior half, converging in anterior half, slightly sinuating before anterior pronotal angles which are slightly acute and drawn forward next to eyes; disc glabrous, moderately densely and distinctly punctate, punctures mostly separated by about 1 to 2 times their own widths, interpunctural integument weakly shagreened with micropunctures, midline impunctate and weakly impressed. SCUTELLUM subtriangular, apex broadly rounded. ELYTRON with disc setigerous, setal length about 1/4 to nearly 1/2 of elytron width; strial channels somewhat irregular but distinct, strial punctures obsolescent, intervals very irregularly uniseriately punctate, punctures distinct, mostly separated by about 2-4 times their own diameters, about half as wide as intervals. PYGIDIUM longer than broad, subscutelliform, apex arcuate, disc shagreened, shallowly subcontiguously punctate, punctures setigerous. LEGS: Anterior tibia moderately robust, tridentate, basal tooth about half as large as strong middle tooth; metatibia with widest corbel diameter little less than half pygidial length, posterior tarsal claws over 1/3 length of segment from which they arise. GENI- TALIA: paramera as in Fig. 12 , with apex only weakly deflexed, ventrobasal emargination shallow, moderately long.

Variation. Length: 6.5 – 8.3 mm, width: 3.0 – 4.0 mm. Clypeal form varies moderately in punctuation, depth of discal concavity, breadth and strength of apical emargination, but shape (lateral margins weakly convex) is similar. Medial mesotibial fringe of denticles varies from 7-12 (usually 9). In one specimen the anterior pronotal angles are nearly right. One paratype has the left antenna deformed, with 3-segmented, shortened club.

Etymology. This species is named for its 4-segmented antennal clubs.

Remarks. This species keys to A dilemma Saylor in Cazier (1953). Saylor (1948) diagnosed that species on the combination of the 4-segmented antennal clubs and hairy elytra; however, the basal club segment in specimens of A. dilemma is narrower than and slightly less than half as long as the more apical segments. In A. quadrilaminata , all antennal club segments are of equal size.

Figures

Figure 10-13. Acoma quadrilaminata Warner: 10) Dorsal habitus. 11) Antenna. 12) Paramera. 13) Dorsolateral view of head and pronotum.