Tesserocerus Saunders, 1837

Peris, David, Kraemer, Mónica M. Solórzano, Peñalver, Enrique & Delclòs, Xavier, 2015, New ambrosia beetles (Coleoptera: Curculionidae: Platypodinae) from Miocene Mexican and Dominican ambers and their paleobiogeographical implications, Organisms Diversity & Evolution (New York, N. Y.) 15 (3), pp. 527-542 : 532-533

Genus: Tesserocerus Saunders, 1837

Type species: Platypus insignis Saunders, 1837

Tesserocerus simojooelensis Peris and Solórzano Kraemer sp. nov.

Figure 3

Etymology: Specific name simojooelensis after Simojovel de Allende ( Mexico), locality where new species was found.

Holotype: Mx-238, Miocene amber from Simojovel de Allende , Chiapas, Mexico; housed at the SMNS (Stuttgart, Germany). The holotype is a complete specimen, the entire habitus visible and well preserved. It is a female by its frons flattened with surface covered by long setae and rounded base of the declivity, something explanate but without protrusions.

Diagnosis: Female. Body 5.5 times longer than wide; head distinctly longer than wide, about two times longer than eye length; scape, mandible insertion, and prosternum strongly pubescent, with long and stout hairs; elytral declivity with three spiniform protrusions on anterior border; protrusions becoming sequentially shorter from the first to the third; metasternum long, impressed near metacoxa for reception of femur, anterior margin of impression armed by one pointed spine.

Description: Body length 5.35, maximum width 0.97 at the elytral apex, 5.5 times longer than wide. Pubescence present along the entire body, very conspicuous on the head, frons, scape, mandibles, and prosternum; elytral disk almost glabrous.

Head distinctly longer than wide, about two times longer than eye length. Eyes lateral, elongate, big, approximately 1.5 times longer than wide, almost flat, slightly visible in dorsal view, subtriangular in outline, anterior margin entire; posterior border delimited by some long and stout setae, as similarly occur along mandible insertions. Vertex coarsely punctured, punctures two times longer than wide. Frons slightly concave transversely, surface with relatively long, fine, erected setae. Antennal insertion basal, closer to mandibles than to the eyes; antennae short extending to cephalic insertion; scape large, slender, extending until the fore margin of the eyes, completely covered by long and stout setae, being longer toward apex; funicle four-segmented; pedicel inserted at the pedicel apex, rounded in shape; antennomere 3 conical, narrower at base and wider apically, as long as the apical diameter; antennomeres 4 and 5 strongly transverse; club compressed, almost round. Mandibles are large, with one large tooth at the apex and one tooth at the apical third of the biting edge, smooth and convex on upper face. Submentum separated on each side from margin of oral fossa by deep cleft.

Pronotum 1.8 times longer than wide, narrower towards the base; pronotal disk of rough appearance, completely covered by rounded punctures; pronotal lateral margins thickened, with a set of long and stout setae along the margins. Scutellum very small, apically pointed. Prosternum long, covered by short and stout setae, precoxal piece on prosternum acutely pointed. Procoxae contiguous.

Elytra subparallel, becoming wider apically, base of elytra slightly wider than base of pronotum. Elytra 2.9 times longer than wide; 1.7 times longer than pronotum. Elytral disk strongly punctured, deeply striate; interstriae 3 carinate along the basal third, interstriae 5 remarked with small tubercles close to the base. Elytral declivity beginning near apical fourth, steep, with three spiniform protrusions on anterior margin of elytral declivity and arising from elytral striae 3, 5, and 7; protrusions become sequentially shorter from the first to the third, although the first and the second are much bigger than the third. Declivity face covered by short and fine hairs and apical margins extending into a short, rounded lobe in each elytron.

Metasternum long, impressed near metacoxa for reception of femur, anterior margin of impression armed by one pointed spine; metacoxae contiguous. Legs short, robust; femora wide, compressed; profemora wider than the rest; protibiae armed with two transverse rugae on the posterior face and a long weakly hooked inner mucro; becoming wider from protibiae to metatibiae; outer face of metatibiae armed by three transverse rugae. Tarsi stout, longer than tibiae in all the legs; tarsomere 1 as long as tarsomeres 4 and 5 combined, protarsomeres 2 and 3 equal in length, protarsomere 4 the shortest, 0.5 times the length of tarsomere 3, tarsomere 5 slightly longer than the previous three combined, slender, with long, slender claws.

Comments: The specimen fits within Tesserocerus by the posterior margin of prothorax strongly procurved in pleural area, submentum separated on each side from margin of oral fossa by deep cleft, procoxae contiguous, scutellum small, slender, pointed, antennal funicle four-segmented (counting the pedicel), eye elongate, 1.5 times longer than wide, anterior margin entire, pronotum 1.8 times longer than wide, precoxal piece on prosternum acutely pointed, and pedicel attached near its apex ( Wood 1993). All Tesserocerus spp. are between 3.0 and 4.5 times longer than wide, including the unique fossil species ( Wood 1993; Bright and Poinar 1994), while T. simojooelensis sp. nov. is 5.5 times longer than wide. Except for this morphological feature, we have decided to keep it in Tesserocerus because all the characters in the new species are consistent with those for this genus in the key to world platypodine genera from Wood (1993).

T. simojooelensis sp. nov. is clearly different from Tesserocerus primus , which is currently a unique fossil species of this genus, described from Dominican amber (Bright and Poinar 1994). The new species is larger, with two rugae on the posterior face of the protibiae and with three spiniform protrusions on anterior margin of elytral declivity, while T. primus is smaller, with one ruga on the posterior face of protibiae, and four spiniform protrusions on the elytral declivity, also with different proportions between them. T. simojooelensis sp. nov. is similar to Tesserocerus retusus in number and position of spiniform protrusions, but the first pair of protrusions in the new species is longer than the second pair, while in T. retusus all the spines are of similar length.

Species already known from Mexican and Dominican ambers

Several species already described from Mexican and Dominican ambers were observed in the amber pieces studied. The difficulty in differentiating between some of these species using the published data justifies the following review, which includes comments on certain aspects of the species (see Table 1 for details).

Figures

Fig. 3 T. simojooelensis sp. nov. from Miocene amber from Simojovel de Allende, Chiapas, Mexico; holotype Mx-238, female, illustration and camera lucida drawing of the dorsal habitus