Yumtaax recticornis (Burmeister, 1847)

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 : 106-110

Yumtaax recticornis (Burmeister, 1847)

Passalus recticornis Burmeister, 1847: 508-509.

Soranus recticornis (Burmeister) [comb. n. by Kaup 1871: 105, 108].

Popilius recticornis (Burmeister) [comb. n. by Gravely 1918: 24, 26].

Petrejoides recticornis (Burmeister) [comb. n. by Reyes-Castillo 1970: 125].

Yumtaax recticornis (Burmeister) [comb. n. by Boucher 2006: 348].

Material examined.

105 specimens (lectotype, paralectotype, and 103 non-type specimens). Lectotype ♂. MEXICO: WB zoologie S. Nr. 812123. (MLU Halle). Paralectotype 1 ♀. MEXICO: no data (MLU Halle).

Non-type specimens (103 total). MEXICO: 1 ♀, Oaxaca, Amatepec (1.6 km N), alt. 1840 m, bosque mesófilo de montaña, II-28-1988 (Reyes, Boucher, C. Castillo). 1 ♂, Carretera Tuxtepec-Oaxaca (87 km), III-21-1967 (R. MacGregor); 1 ♀, (88 km), alt. 2350 m, IV-4-1986 (A. Ibarra); 1 ♂, 1 ♀, (119 km), X-6-1973 (J. Mateu); 4 ♂, 2 ♀, (153 km), alt. 2800 m, X-7-1973 (J. Mateu). 1 ♀, Cerro Pelón (2.8 km), V-18-1980 (C. Castillo, M. L. Castillo, G. Quintero, E. Rivera); 3 ♀, (11.4 km NE), alt. 2170 m (P. Reyes et al.). 1 ♀, Comaltepec, Brecha 60 (unknown locality), V-18-1980 (C. Castillo, M. L. Castillo, G. Quintero, E. Rivera); 3 ♂, 2 ♀, (4.5 km), V-18-1980 (C. Castillo, M. L. Castillo, G. Quintero, E. Rivera). 1 ♂, 4 ♀, Comaltepec, Galera San Isidro (800 m), alt. 2000 m, V-17-1980 (C. Castillo, M. L. Castillo, G. Quintero, E. Rivera); 3 ♂, 5 ♀, (3.6 km), alt. 2160 m, V-17-1980 (C. Castillo, M. L. Castillo, G. Quintero, E. Rivera). 1 ♀, La Esperanza, alt. 1670 m, V-16-1980 (C. Castillo, G. Quintero, M. L. Castillo, E. Rivera); 4 ♂, 3 ♀, (3.5 km N), alt. 1670 m, bosque mesófilo de montaña, III-1-1988 (Reyes, Boucher, Castillo); 1 ♀ (4 km), alt. 1800 m, V-20-1980 (C. Castillo, M. L. Castillo, G. Quintero, E. Rivera); 5 sex unknown, (6.8 km), alt. 1820 m, II-25-1984 (P. Reyes et al.); 1 sex unknown, (13.1 km), alt. 2030 m, II-25-1984 (P. Reyes et al.); 3 sex unknown, (14.1 km), alt. 1985 m, II-25-1984 (P. Reyes et al.); 2 sex unknown, (103.1 km), alt. 2030 m, II-25-1984 (P. Reyes et al.). 1 sex unknown, San Juan Lachao Viejo, km 85 de Sola de Vega (N 16°13.220' W 97°08.913), alt. 1858-1870 m, bosque mesófilo de montaña, VIII-6-2004 (K. Araya). 30 sex unknown, San Miguel Talea de Castro (8 km SE) (N 17°19.620' W 96°17.403), alt. 2082 m, VII-22-2007 (O. Francke, H. Montaño, A. Valdéz, C. Santibañez, A. Ballesteros). 3 ♂, 4 ♀, Sierra de Juárez, alt. 2000 m, VI-2-1995 (G. Nogueira). 2 ♂, 1 ♀, Totontepec (3.4 km S), alt. 1940 m, bosque mesófilo de montaña, II-29-1988 (Reyes, Boucher, Castillo). 3 ♂, 3 ♀, Valle Nacional (32 miles S), V-21/24-1971 (H. Howden); 1 ♀, (105-117 km E), IV-1964 (C. R. Rotger).

Diagnosis.

Yumtaax recticornis is a small (18.0-21.0 mm), macropterous species and is a member of the Y. imbellis clade (Fig. 4). This species is diagnosed by the following character combination: the clypeus is inclined (shared with Y. jimenezi , Y. imbellis , Y. mazatecus , Y. nebulosus , Y. olmecae ; clypeus vertical in Y. veracrucensis , Y. laticornis , Y. cameliae ), surface concave (flat in other members of Yumtaax ), and the anterior border is concave (shared with Y. olmecae ; flat in other members of Yumtaax ); mesofrontal structure (MFS) of the “falsus” type (see Reyes-Castillo 1970) (shared with all members of Yumtaax except Y. cameliae that has a MFS of the “striatopunctatus” type) with the central tooth largely free (shared with Y. veracrucensis , Y. laticornis , Y. cameliae , Y. mazatecus ; fused with frontal ridges in Y. jimenezi , Y. imbellis , Y. nebulosus , Y. olmecae ), central tooth directed dorsally (shared with Y. imbellis , Y. nebulosus , Y. olmecae ; directed dorsally and anteriorly in Y. jimenezi , Y. mazatecus ; directed anteriorly in Y. veracrucensis , Y. laticornis ; elevated in the posterior half bending abruptly forward in the anterior half in Y. cameliae ), central tooth not reaching the anterior border of the frontoclypeal suture (shared with Y. jimenezi , Y. imbellis , Y. mazatecus , Y. nebulosus , Y. olmecae ; reaching the clypeus in Y. laticornis , Y. cameliae , Y. veracrucensis ); and large eyes (shared with Y. imbellis ; eyes moderately reduced in Y. veracrucensis , Y. cameliae , Y. jimenezi , Y. nebulosus , Y. olmecae ; strongly reduced in Y. laticornis , Y. mazatecus ).

Dimensions

(mm) (n = 12). Total length 18.0-21.0 ( χ = 19.0); elytral length 10.0-11.5 ( χ = 11.0); pronotal length 3.5-5.0 ( χ = 4.5); pronotal width 5.5-6.0 ( χ = 5.5); humeral width 5.5-6.5 ( χ = 6.0).

Redescription of lectotype

(Fig. 5). Head (Fig. 5C). Labrum: anterior border concave, dorsal surface smooth and glabrous medially, punctate and setose apicolaterally, apically, and basally; anterior edge excavated. Clypeus: inclined, rectangular, concave, shiny, and smooth. Frontoclypeal suture: concave and opaque; external tubercles rounded, directed anteriorly and laterally. Frontal area: inclined, concave, smooth and shiny; frontal ridges present without inner tubercles. Frontal fossae: punctate and setose. Mesofrontal structure (MFS): of the “falsus” type (see Reyes-Castillo 1970); base subparallel and as wide as the lateral ridge of MFS; center horn short with apex rounded, largely free and directed anteriorly and dorsally (Fig. 5D), not reaching the posterior margin of clypeus, dorsally without micro-punctures; base of center horn wide, narrowing gradually until apex; dorsal fossa present at the base of MFS. Occipital fossa: shallow posteriorly and deeper laterally, connected with the frontal fossae. Posterior occipital sulcus biconcave. Supraorbital ridge: bituberculate, anterior tubercle larger than posterior tubercle; posterior half of supraorbital ridge not bifurcated. Canthus: with apex rounded, covering less than 1/3 of eye, not expanded distally. Eyes large (distal edge of the eye surpassing distal edge of the canthus), width = 0.5 mm (each eye). Head width (between posterior tubercles of the supraorbital ridge) = 3.0 mm. Ratio of sums of both eye widths/total head width = 0.36; postocular area punctate and setose. Ligula: tridentate, 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 present and rugose. Hypostomal process: with lateral depression; separated from mentum by a distance shorter than the width of the anterior width of hypostomal process. Infraocular ridge (e.g., Fig. 3): short and narrow anteriorly. Mandible: with 3 apical teeth; internal tooth of left mandible bidentate (teeth 1 and 2 of internal tooth fused); dorsal tooth occupies less than half length of the mandible. Pronotum: anterior angles rounded. Anterior fossae of marginal sulcus punctate. Lateral fossae with scattered punctures. Marginal groove lacking punctures. Prosternum: opaque; prosternellum with anterior half and lateral edges opaque and posterior half and middle area shiny. Scutellum: smooth and glabrous. Mesosternum: with lateral areas opaque. Metasternum: with setae anterolaterally, lacking punctures in lateral margins of metasternal disc. Lateral fossae wide across 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 (Fig. 5E): femur I with longitudinal anteroventral groove weakly developed, not reaching distal end of femur, posteroventral half pubescent; setae long, dense, reddish. Abdomen: last sternite with marginal groove complete (Fig. 5B). Aedeagus (Fig. 5F, G, and H) (description based on non-type material): dorsal view phallus elongated (longer than wider). In ventral view distal edges of the phallus more or less at the same level of distal edges of parameres.

Variation.

The paralectotype and other specimens vary from the lectotype by the following characteristics: frontoclypeal suture varies from opaque to shiny, from concave to almost straight; frons and clypeus inclined to nearly vertical (always concave); concavity of frons and clypeus vary from strongly developed to nearly flat. Internal tubercles strongly developed or absent; frontal ridges always present, but not always terminating in internal tubercles; ratio of eyes and head width varies from 0.32-0.57; supraocular ridge weakly developed or absent. Occipital sulcus biconcave to concave in a few individuals. Small portion of individuals with frontal ridges fused to the base of the central horn of MFS (apex of the central horn always free).

Distribution.

The lectotype and paralectotype are labeled “Mexico” ( Burmeister 1847). Castillo and Reyes-Castillo (1984) suggested the Sierra de Juarez in Oaxaca, Mexico, as the possible type locality. The species is known only from cloud forest (1424-2986 m elevation) in Oaxaca, Mexico.

Remarks.

Originally, this species was thought to be widely distributed across the Sierra Madre Oriental, the Mexican Transvolcanic Belt, and Sierra Madre del Sur ( Reyes-Castillo 1970, Castillo and Reyes-Castillo 1984, Boucher 2006). Our phylogenetic analysis (Fig. 4), as well as close examination of morphological characters, provide evidence that Y. recticornis s. l. is composed of at least two cryptic species: Y. recticornis (" Y. recticornis OM" in the Y. imbellis clade, Fig. 4 and Suppl. materials 2-4) and Y. jimenezi sp. n. (" Y. recticornis VM" in the Y. laticornis clade, Fig. 4 and Suppl. materials 2-4). Based on comparison with the lectotype and one paralectotype of Y. recticornis , this name should be applied to Y. recticornis OM. The following character states provide evidence that Y. recticornis OM is conspecific with Burmeister’s concept of Y. recticornis : large eye size (distal edge of the eye surpassing distal edge of the canthus), shape of the central tooth of the MFS (base subparallel and as wide as the lateral ridge of the MFS; center horn short with apex rounded, largely free and directed anteriorly and dorsally [Fig. 5D]), and shape of the frons and clypeus concave (rather than straight as in Y. jimenezi ). Castillo and Reyes-Castillo (1984) suggested that eye size variation among Y. recticornis s. l. was dependent upon the locality of the population (populations in Oaxaca possess large eyes; populations in Veracruz possess small eyes). Characters of the internal tooth of the left mandible and aedeagus are described based on the paralectotype and non-type material because the mandibles of the lectotype are closed (thus making it impossible to determine the state of this character in this specimen).