Yumtaax jimenezi Beza-Beza, Reyes-Castillo & Jameson

Beza-Beza, Cristian Fernando, Beck, James, Reyes-Castillo, Pedro & Jameson, Mary Liz, 2017, Phylogeny of the genus Yumtaax Boucher (Coleoptera, Passalidae, Proculini): Taxonomic and evolutionary implications with descriptions of three new species, ZooKeys 667, pp. 95-129 : 119-122

Yumtaax jimenezi Beza-Beza, Reyes-Castillo & Jameson sp. n.

Material examined.

27 type specimens.

Holotype ♂. MEXICO: Veracruz, Calcahualco, Tecuanapa. Bosque mesófilo, alt. 2400 m V-2/3-1992 ( Capistrán and Delgado) (IEXA).

Paratypes (26 total). MEXICO: Veracruz: 10 ♀, 15 unknown sex, Calcahualco, Tecuanapa, bosque mesófilo, alt. 2400 m, V-2/3-1992 ( Capistrán and Delgado). 5 ♂, 8 ♀, 34 sex unknown, Calcahualco, Tecuanapa, bosque mesófilo, alt. 2400 m, V-1992 ( Capistrán and Delgado). 14 ♀, Calcahualco, Tecuanapa, bosque mesófilo, alt. 2200 m, VI-1992 ( Capistrán and Delgado). 1 ♂, Calcahualco, Dos Caminos, II-29-1992, alt. 1415 m, bosque de encino-pino, dentro de Quercus sp. (R. Novelo, F. Capistrán and L. Delgado). 1 ♀, 2 sex unknown, Calcahualco, Nueva Vaquería (1 km before), II-28-1992, alt. 2700 m, bosque de pino-encino, en tronco (R. Novelo, F. Capistrán and L. Delgado). 2 ♀, Veracruz, Calcahualco, 1 km antes de Nueva Vaquería, 2700 m, VI-1992, (L. Delgado and Capistrán) (CFBB, IEXA). 1 ♂, Cosautlan, Los Laureles, alt. 2680 m, VIII-27-1999 (J. P. Lumaret). 4 sex unknown, Orizaba, Sallé, Mex. Collection ( Sallé) (BMNH). 1 sex unknown, Mexico (Truqui) (BMNH).

Diagnosis.

Yumtaax jimenezi is a small (18.5-23.0 mm) macropterous species, and it is part of the Y. laticornis clade (=Fig. 4). This species is diagnosed by the following character combination: clypeus is inclined (shared with Y. recticornis , Y. imbellis , Y. mazatecus , Y. nebulosus , Y. olmecae ; vertical in Y. laticornis , Y. cameliae , Y. veracrucensis ) and with the anterior border straight (shared with other members of Yumtaax except for Y. recticornis and Y. olmecae that have the anterior border of clypeus concave); MFS of the “falsus” type (see Reyes-Castillo 1970) (shared with all members of Yumtaax except Y. cameliae which has the MFS of the “striatopunctatus” type), with the central tooth that is not free (fused with frontal ridges) (shared with Y. imbellis , Y. nebulosus , Y. olmecae ; largely free in Y. recticornis , Y. veracrucensis , Y. laticornis , Y. cameliae , Y. mazatecus ), directed dorsally and anteriorly (shared with Y. mazatecus , directed dorsally Y. recticornis , Y. imbellis , Y. nebulosus , Y. olmecae ; directed anteriorly in Y. veracrucensis , Y. laticornis ; elevated in the posterior half bending abruptly forward in the anterior half in Y. cameliae ), and not reaching the clypeus (shared with Y. recticornis , Y. imbellis , Y. mazatecus , Y. nebulosus , Y. olmecae ; reaching the clypeus in Y. laticornis , Y. cameliae , Y. veracrucensis ); and moderately reduced eyes (shared with Y. veracrucensis , Y. cameliae , Y. nebulosus , Y. olmecae ; large in Y. recticornis , Y. imbellis ; strongly reduced in Y. laticornis , Y. mazatecus ).

Dimensions

(mm) (n = 12). Total length 18.5-23.0, ( χ = 20.5); elytral length 11.5-14.0, ( χ = 12.5); pronotal length 4.0-6.0, ( χ = 5.5); pronotal width 5.5-7.0, ( χ = 6.5); humeral width 5.5-7.0, ( χ = 6.5).

Description of holotype

(Fig. 9). Head (Fig. 9C). Labrum: anterior border concave, dorsal surface smooth and glabrous medially, and punctate and setose in the apicolaterally, apically, and basally; anterior edge excavated. Clypeus: inclined, rectangular, shiny, and smooth. Frontoclypeal suture: straight, and shiny. External tubercles rounded and directed dorsally. Frontal area: inclined, smooth, and shiny, frontal ridges present finishing in inner tubercles. Frontal fossae: punctate and setose. Mesofrontal structure (MFS): of the “falsus” type (see Reyes-Castillo 1970); base subparallel and narrower than the MFS’ lateral ridge; center horn short with apex rounded, not free (fused with frontal ridges) and directing dorsally (Fig. 9D), not reaching the posterior margin of clypeus (Fig. 9C, D), dorsally without micro-punctures; base of the center horn narrow not narrowing down along its length (central tooth tubercle like shape [Fig. 9C, D]); dorsal fossa present at the base of MFS. Occipital fossa: shallow posteriorly and deeper laterally not connected to frontal fossae. Posterior occipital sulcus sinuate. Supraorbital ridge: bituberculate, tubercles of similar size; posterior half of supraorbital ridge not bifurcated. Canthus: with apex rounded covering less than 1/3 of the eye, expanded distally. Eyes: reduced (distal edge of the eye more or less at the distal edge of the canthus), width = 0.5 mm (each eye). Head width = 3.5 mm. Ratio of sums of both eyes widths/total head width = 0.24; postocular area punctate and setose. Ligula: tridentate, with central tooth surpassing apex of lateral teeth, lateral teeth rounded; setose punctures present in discal area; posterior border convex. Mentum: lateral lobes rounded and wide, with setose punctures. Basomedial portion protruding ventrally; anterior border at middle convex; basal fossae absent. Hypostomal process: without lateral depression; separated from mentum by a distance shorter than the wide of the anterior width of hypostomal process. Infraocular ridge absent. Mandible: with 3 apical teeth; internal tooth of left mandible bidentate; dorsal tooth occupies less than half length of the mandible. Pronotum: anterior angles rounded. Anterior fossae of marginal sulcus impunctate. Lateral fossae with heavy punctures. Marginal groove lacking punctures. Prosternum: opaque. Prosternellum anterior half opaque and lateral edges and posterior half shiny. Scutellum: smooth and glabrous. Mesosternum: with anterolateral areas opaque. Metasternum: with setae in anterolaterally, without punctures in lateral margins of metasternum disc. Lateral fossae wide across the metathorax, with setose punctures. Elytra: anterior border straight. Meeting point of striae 1-10 (see Reyes-Castillo 1970) with one line of punctures. Wings: well developed. Legs: femur I with longitudinal anteroventral groove weakly developed in the proximal half and strongly developed on the distal end of the femur, posteroventral half pubescent; setae long, sparse, reddish. Abdomen: last sternite with marginal groove complete (Fig. 9B). Aedeagus (Fig. 9E, F, G): in dorsal view phallus globose (wider than long). In ventral view distal edges of phallus surpassing the distal edge of the parameres.

Variation.

Frontoclypeal suture can be from opaque to shiny; internal tubercles from strongly to weakly marked but always present; ratio of eyes and head with varies from 0.18-0.32; supraocular ridge from weak to absent; hypostomal process with weak lateral depression to lateral depression absent; prosternellum varies from anterior half opaque and lateral edges and posterior half shiny to anterior half and lateral edges opaque and posterior half and middle shiny to completely opaque; femur I longitudinal anterior-ventral groove from weak in the proximal half to absent; femur I longitudinal anterior-ventral groove from strongly developed in the distal half to absent.

Etymology.

This species is named in honor of Passalidae worker Dr. Larry Jiménez-Ferbans who assisted in collecting trips supporting this study.

Distribution.

This species is known from cloud forest (bosque mesófilo) at 2400 m elevation from the state of Veracruz, Mexico.

MEXICO: Veracruz: Calcahualco (Tecuanapa, Dos Caminos, Nueva Vaquería [1 km before]).

Remarks.

Yumtaax jimenezi is a cryptic, widespread species that has been confused with Y. recticornis . Previously, Y. recticornis s. l. was thought to be broadly distributed in Mexico from the Sierra Madre Oriental in the Mexican Transvolcanic Belt and Sierra Madre del Sur ( Reyes-Castillo 1970, Castillo and Reyes-Castillo 1984, Boucher 2006). Phylogenetic analysis (Fig. 4 and Suppl. materials 2-4) and close examination of morphology provide evidence that Y. recticornis s. l. comprises two cryptic species [ Y. recticornis (= Y. recticornis OM) and Y. jimenezi ( Y. recticornis VM)].

These species are distinguished by eye size (small in Y. jimenezi and large in Y. recticornis ), shape of the central tooth of the MFS (center horn short with apex rounded, not free [fused with frontal ridges] and directed dorsally [Fig. 9D] in Y. jimenezi ; center horn short with apex rounded, largely free and directed anteriorly and dorsally [Fig. 5D] in Y. recticornis ), and the shape of the surface of the frons and clypeus (concave in Y. recticornis versus flat in Y. jimenezi ). Interestingly, the reduced eye size in Y. jimenezi results in the distal expansion of the canthus. Based on seven exemplars, phylogenetic analysis (Fig. 4) strongly supports Y. jimenezi as a unique lineage (1.0 PP/100 BS).