Cyphosterna Chevrolat, 1862

Cyphosterna Chevrolat, 1862 View in CoL

Type species: Cyphosterna quadrilineatum Chevrolat, 1862 (monobasic)

Cyphosterna (Dioxiotes) 4-lineata Chevrolat 1862: 756, 757

Cyphosterna Thomson 1864: 205 View in CoL , 432; Lacordaire 1869: 188; Bates 1880:86; Zajciw 1960: 144; Zajciw 1969: 225; Monné 1994: 67

Neotaranomis Chemsak and Linsley 1982: 71 View in CoL ; Monné 1994: 33 (new synonymy)

Redescription. Form moderate sized to large, tapering posteriorly. Head small, front convex, subvertical, subquadrate, mid-cranial sulcus narrow, canaliculate, extending arcuately from postclypeus to vertex between upper lobe of eyes, integument of front seamlessly fused with postclypeus, integument above postclypeus on either sides below antennal insertion with broad, shallow, oblique depression; genae subquadrate, anterior margins of lower eyes separated from base of mandibles; palpi short, slightly unequal, apical segments not expanded, apex truncate, outer edge of maxillary palpi convex; mandibles simple, sides arcuate, dorsum impressed on outer edges, apices simple, not emarginated; eyes moderately large, finely faceted, upper lobes small well separated, lower lobe large, deeply emarginate, not embracing antennal insertions; antennal tubercles prominent; antennae slender, elongate, longer than body in male, not or scarcely so in female, 11-segmented, antennomeres externally carinate, 11 th antennomere slender, vaguely to non-appendiculate. Pronotum broader than long, narrower than base of elytra at humeri; apex narrower than base; disc moderately inflated, excavated and tuberculate at sides, dorsally callused; prosternum with intercoxal process level with coxae, narrower than coxal cavities, obtusely keeled or ridged in middle, apex vertical, abruptly declivous behind, coxal cavities wide open behind; mesosternum with intercoxal process tuberculate, protuberant above coxae, abruptly declivous anteriorly; posterior margin strongly emarginate in middle, lobed on sides and slightly overlapping mesocoxae; metepisterna slightly broader in front. Scutellum elongate, small. Elytra tapered apically, each with prominent costae, apices variable. Legs slender; metafemora extending to about elytral apices or longer in male, attaining elytral apices in female; pro- and mesotarsi broad; metatarsi narrow, elongate, tarsomere III cleft to base. Abdomen normally segmented.

The following species are included in this genus: Cyphosterna quadrilineatum Chevrolat, 1862 ( Fig. 459– 477 View Figures 459–477 ); C. sinaloanum Chemsak and Linsley, 1982 new combination ( Fig. 478–488 View Figures 478–488 ); C. atropurpureum, Chemsak and Noguera, 2001 new combination ( Fig. 489–499 View Figures 489–499 ).

Discussion. According to Chevrolat (1862: 756), Cyphosterna is a genus placed near Entomosterna Chevrolat , which also included the genera Triacetelus Bates , Gambria Chevrolat , and Chevrolatella Zajciw. Its form is elongate with rounded head, and front that is slightly convex, truncated in the middle, furrowed longitudinally (mid-cranial sulcus) with two small, raised antennal tubercles between the antennal insertion. The palpi are composed of segments of almost equivalent length with last segments slightly more elongate, subcylindrical and truncated at apices. The mandibles are medium sized and arched. Labrum is transverse and emarginated apically, and clypeus is wide, linear, and rimmed. The eyes are large, rounded above and emarginated below. The antennae are filiform, eleven segmented, and elongate, longer than body in males, and reaching two-third length of elytra in females. Each antennomeres are almost equivalent in length, except for the second antennomeres that are short. The scape is clubbed, and apices of antennomeres III to X slightly angulate. The pronotum is as long as wide, rounded laterally on anterior half, arcuately impressed on posterior half with an angular spine on each side in the middle. The apex of pronotum is transverse, and base is arcuate (or margin lobed at middle), narrowly rimmed with sides extending over humeri, and disc convex and uneven. Scutellum is triangular and impressed medially. Elytra are slightly wider than prothorax, obtusely rounded over humeri, and parallel sided. The elytral discs are moderately, evenly convex and apices are emarginate. Legs are punctate and elongate, and femora are tapered. The metafemora exceed apices of elytra by a quarter of its length and terminating with two small spines. The tibiae are linear, slightly widening at apices, and terminating with two apical spines. The first and last articles of metatarsi are elongate with tarsal claws simple. Prosternum is narrow, flat, and arched. Mesosternum is widened anteriorly, and the intercoxal process is truncate and emarginated in the middle of the posterior margin with a shiny tubercle with obtuse spine in middle. Anterior coxae are globose, coxal cavities are rounded, strongly depressed above coxae, and slightly angulate exteriorly. Metasternum is rectangular. Abdomen is elongate, rounded at apex and composed of five segments with the last three segments almost equivalent in length.

At the time when Cyphosterna was described, Chevrolat included the following five additional species in this genus: Cyphosterna emarginata (i.e., Triacetelus emarginatus ( Chevrolat, 1862: 758)) ; C. bicolor (i.e., Gambria bicolor ( Chevrolat, 1862: 758)) ; C. tripunctata (i.e., Chevrolatella tripunctata ( Chevrolat, 1862: 759)) ; C. ornaticollis (i.e., Chevrolatella tripunctata ( Chevrolat, 1862: 759)) ; and C. nigripennis (i.e., Gambria nigripennis Chevrolat, 1862: 760 ). Thereafter, Lacordaire (1869: 188) redescribed Cyphosterna based on a single specimen of C. quadrilineata , and commented that the abdominal segment two being much longer than four and five, almost covering three, and notes, “ This last peculiarity is perhaps accidental in the single copy that I have in front of me, but there would always remain the unusual length of the segment two,” and further commented that he did not notice this peculiar structure of the abdomen in other genera preceding Cyphosterna (i.e., Muscidora Thomson , and Entomosterna Chevrolat ) and the three following genera (i.e., Gambria Chevrolat , Eriphus Audinet-Serville , and Perarthrus LeConte ), which makes this genus very distinct ( Lacordaire, 1869: 186–191). Bates (1880: 86) thereafter noted that “ Lacordaire, on the other hand, proposed to limit Cyphosterna to those species in which the second ventral segment in male was abnormally lengthened. As he knew only one of Chevrolat’s species which possessed this character, he referred the rest doubtfully to Gambria , a view which we provisionally follow.” Therefore, Bates limited Cyphosterna to species with second ventral segment of abdomen with abnormal length based on Lacordaire’s observation. This proposed limit on Cyphosterna is incorrect and is likely to be a peculiarity of the single specimen examined by Lacordaire. This conclusion is supported by the original description of this genus by Chevrolat (1862: 756), which states the abdomen as “composed of five segments with last three segments almost equivalent in length” (i.e., “ Abdomen allongé arrondi au sommet, composé de cinq segments; les trois terminaux presque d’égale grandeur. ”). It is likely that the single specimen examined by Lacordaire had abdominal segment three to five that were pushed back proximally into segment two giving the appearance of longer segment two followed by a very short segment three.

The etymology of Cyphosterna is provided by Chevrolat (1862: 756) as Ancient Greek: Κῦφος (“ Cypho -” meaning “bump” or “knobbed” or “bosse” in French) and στέρνον (“ -sterna ” meaning “sternum”) referring to protuberant mesosternum. Since the name “ Cyphosterna ” has a gender-neutral ending “ -sterna ” the subsequent species names which follows must also be gender neutral as follows: “ quadrilineatum, sinaloanum , and atropurpureum .”