Cenocephalus Chapuis, 1865

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 : 529-531

Genus: Cenocephalus Chapuis, 1865

Type species: Cenocephalus thoracicus Chapuis, 1865

Cenocephalus tenuis Peris and Solórzano Kraemer sp. nov.

Figure 2

Etymology: Specific name tenuis is the Latin word for ‘slender’.

Holotype: Mx-379, Miocene amber from Simojovel de Allende , Chiapas, Mexico; housed at the SMNS (Stuttgart, Germany). The holotype is a complete specimen clearly collapsed internally by taphonomic processes but with all the necessary characters clearly visible. It is female by its frons strongly flattened covered with long setae.

Allotype: Mx-354, the locality and depository are the same as the holotype, as syninclusion with one Arachnida, three Diptera : ( Ceratopogonidae , Cecidomyiidae , and Psychodidae ) and one Psocoptera.

Paratype: Mx-213, the locality and depository are the same as the holotype, as syninclusion with one specimen of Cenocephalus hurdi and one possibly Anthribidae ( Coleoptera : Curculionoidea). It is a female.

Diagnosis: Female with slim body, elytral declivity very short, it is margin-armed by small spiniform protrusions, apical margin extending into a short, acute process, face of declivity very convex with a pair of acute spiniform protrusions into the interstriae 3, protibiae armed with two transverse rugae and outer face of metatibiae armed by four transverse rugae.

Description: Female. Body length 3.64 without mandibles, maximum width 0.59 at the elytral apex, 6.2 times longer than wide. Body completely collapsed. Pubescence present dorsally in the head (long hairs) and elytra (short hairs), pronotum glabrous.

Head distinctly longer than wide, approximately two times longer than eye diameter, slightly constricted behind the eyes, marked dorsally. Eyes lateral, small, round, easily visible in dorsal view, very finely faceted. Frons as wide as head, strongly concave transversely, surface with long, straight setae, which are curved on periphery. Limit between the frons and the rostrum unidentifiable. Antennae insertion basal, antennae length very short, not extending to cephalic insertion. Scape straight, only slightly curved at the insertion with the head, extending until the fore margin of the eyes; funicle four-segmented; very little pedicel inserted at the scape apex, as wide as long; antennomere 3 conical, narrower at base and wider at apex, as long as the apical diameter; antennomeres 4 and 5 strongly transverse; club compressed, almost round. Mandibles 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 2.1 times longer than wide, wider at apical fifth, narrower towards the base; pronotal disk smooth. Posterior margin of prothorax strongly procurved in pleural area. Scutellum small, slender, apically pointed. Procoxae contiguous, precoxal piece on prosternum obtusely pointed.

Elytra subparallel, becoming wider apically, base of elytra as wide as base of pronotum. Elytra 2.9 times longer than wide (measured from the base to the declination and the wider, apical portion); 1.5 times longer than pronotum. Elytral disk shallow punctured, deeply striate, total number of striae and interstriae not discernible. Bases of interstriae 3 and 5 transversely rugose; interstriae 3 carinate along the basal third, interstriae 5 subcarinate close to the base. Elytral declivity beginning near apical fourth, convex, lateral margin evenly arcuate and armed by short spiniform protrusions, a pair of acute spiniform protrusions into the face of the declivity, interstriae 3; apical margin extending into a short, acute process.

Plant

Hymenaea Linnaeus 1753

H. allendis Calvillo-Canadell, 2010

Cevallos-Ferriz and Rico-Arce

H. courbaril Linnaeus 1753

H. mexicana Poinar and Brown 2002

H. protera Poinar 1991

H. oerrucosa (Gaertner) Oliver 1791

Animal

Acanthotomicus Blandford 1894 A. hymenaeae Eggers 1933 Batrachorhina Chevrolat 1842 Chaetastus Numberg 1953 Cladoctonus Strohmeyer 1911 C. ruber Bright and Poinar 1994 Coccotrypes Eichhoff 1878 Coecephalophonus (Schedl) 1965 Cryptocarenus Eggers 1937 Electroborus Cognato 2013 Hypothenemus Westwood 1836 Mitosoma antiquus Bright and Poinar 1994 Mitosoma biconicus Bright and Poinar 1994 Nesanoplium puberulum (Fleutiaux and Sallé) 1889 Platypicerus (Nunberg) 1953 Scolytogenes Eichhoff 1878 Tesserocerus primus Bright and Poinar 1994 T. retusus Guérin-Méneville 1838 Wendilgarda Keyserling 1886

Differences between plants and animals are presented here, ordered alphabetically

Mesosternum with mesepisternum convex, unarmed. Metasternum long, with distinct femoral impression; metacoxae contiguous. Legs long; femora wide, compressed; protibiae with two transverse rugae and a long weakly hooked inner mucro; outer face of metatibiae armed by four transverse rugae. Tarsi slender, longer than tibia; tarsomere 1 as long as the following tarsomeres combined; tarsomeres 2 and 3 equal in length; tarsomere 4 the shortest, 0.5 times the length of tarsomere 3, tarsomere 5 as long as the previous three combined, slender, with long, slender claws.

Male. Of similar size, proportions, and general sculpture. It differs from the female in frons feeble depressed, glabrous, and elytral declivity with spiniform protusions on the interstriae 3 more strongly developed.

Comments: The specimens fit within Cenocephalus 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 with circular profile in lateral view, mesepisternum convex, unarmed, precoxal piece on prosternum obtusely pointed, second segment on antennal funicle longer than wide, outer face of metatibiae armed by four transverse rugae, elytral declivity convex, base of declivity armed by spiniform protrusions, and Central American distribution (Browne 1971; Schedl 1972; Wood 1993).

The unique character that differentiates this genus from the Magalasy Mitosoma is the current distribution, which is a relatively weak piece of evidence when describing fossils (see B Discussion^). C. tenuis sp. nov. has several similarities with the African genus Chaetastus , but they differ in the antennae type and elytral disk (see also B Discussion^ about taxonomic remarks). These characters were highlighted by Browne (1971), who described them as essential in differentiating Chaetastus from Mitosoma and Cenocephalus . However, several other characters in C. tenuis sp. nov. warrant a more correct assignment of the new species in Cenocephalus (although see also B Discussion^ about taxonomic remarks); these include dimensions and proportions of the body parts, which lack an apparent transverse band of fine pores along basal portion of the pronotal disk, number of transverse rugae at the pro- and metatibiae outer surface, position and size of spines along the declivity face and margins, and American distribution.

C. tenuis sp. nov. is not as stout as members of this genus tend to be, and the pronotum is slender; however, the set of characters are concordant with Cenocephalus . The fossil species Cenocephalus exquisitus , Cenocephalus antiquus , and Cenocephalus spinatus also have a slender pronotum. Although C. tenuis sp. nov. has a similar spine distribution along the declivity to the fossil C. biconicus , the new species is more slender, with the declivity margin armed with short spiniform protrusions and face of declivity convex; C. biconicus is more robust, with the declivity margin unarmed and its face obliquely truncated.

Figures

Fig. 2 C. tenuis sp. nov. from Miocene amber from Simojovel de Allende, Chiapas, Mexico; a holotype Mx-379, female, illustration and camera lucida drawing of the dorsal habitus; b holotype, detailed camera lucida drawing of the elytral declivity; c allotype Mx-354, male, detailed illustration of the head and the antennae; d paratype Mx-213, detailed illustration of the elytral declivity