Diceroderes mexicanus Solier, 1841

Smith, Aaron D. & Cifuentes-Ruiz, Paulina, 2015, Revision of Diceroderes Solier (Coleoptera: Tenebrionidae: Toxicini: Eudysantina), with Descriptions of Four New Species, The Coleopterists Bulletin (mo 14) 69, pp. 55-72 : 58-62

Diceroderes mexicanus Solier, 1841

( Figs. 3–4 , 13–23 )

Diceroderes mexicanus Solier 1841: 49 .

Type Material. LECTOTYPE ( Figs. 13–14 ), designated here, (male) labeled ( Fig. 15 ): on green circle (a) “ Diceroderes / mexicanus / [illegible Mexique Sol.] / [illegible]”; (b) on green paper “ Mexique ”; (c) on green paper “ Diceroderes Solier / Taurus du Breme [?] / Colombia / [?] Gre ( Genre in French ) Protomenes Dej.”; (d) on red paper, “ LECTOTYPE / Diceroderes / mexicanus / Solier / des. ADSmith 2015” ( MNHN) . PARALECTOTYPE ( Figs. 16–17 ), designated here, (female) labeled ( Fig. 18 ): on green circle (a) “ Diceroderes / mexicanus / Colombia / [illegible] Sol. (by Solier ) 67”; (b) on green paper “ Diceroderes Solier / Prosomenes Dejean / mexicanus Solier / [see label] / Mexico ”; (c) on yellow paper, “PARALECTO- TYPE / Diceroderes / mexicanus / Solier / des. ADSmith 2015” ( MNHN) .

Additional Material Examined. Thirty-two specimens. MEXICO: Puebla, Apulco, 1 ex (♂), 21-I-2001, L. Cervantes coll. ( CNIN). MEXICO: Veracruz, Ixhuacán, Puente de Dios , 1 ex (♂) , 15-V-2012, E. Arriaga coll. ( CNIN). MEXICO: Puebla, Necaxa , 1200 m.a.s.l., 2 ex. (♂ ♀) , 27-VII- 1947, C. Bolívar & I. Piña coll. ( CNIN). MEXICO: Veracruz, 5 km N de Tlaquipa , 1 ex (♂) , 22-III-2003, M. G.- París & G. Parra coll. ( CNIN). MEXICO: Puebla, RMO Xocoyolo , 1 ex (♂) , 4-X-2001, M. G.- París & G. Parra coll. ( CNIN) . MEXICO: Veracruz, 19 km NW Ciudad Mendoza , VII-11-74 J. Powell, J. Chemsak, Pinus , 1 ex (♂, EMEC) . MEXICO: Hidalgo, Hwy. 105 2.7 mi. N. Tlachinol, 5000 ′ 10-VI-1983; G.B. Marshall C.W. & L.O’ Brien, berlese cloud forest litter, 1 ex (♀, FSCA). MEXICO: Veracruz, 19km NW C.Mendoza VIII-13-1987, 1900m J.T. Doyen, 1 ex (♂, EMEC). MEXICO: Veracruz, 17 km SSE Misantla 31 Jul 1990 1200 m el. J.K. Liebherr CAS-CU-UCB Field Exp., 1 ex (♀, CUIC). MEXICO: Veracruz, Jalapa 24-XII-1979 P.W. Kovarik, coll., 1 ex (♀, TAMU). MEXICO: Veracruz, Microondas 10 air km NNW Huatusco 14 Aug 1987 el. 2000 m MEXICO: Field Party 1987: J.K. Liebherr D.A. Millman, 3 ex (♂ ♀♀, CUIC) . MEXICO: Veracruz, 10 air km NNW Coscomatepec 2000m VIII-14- 1987 J.T. Doyen, 2 ex (♂ - EMEC, ♀ - RLAC) . Las Vigas, Vera Cruz. Höge, 1 ex (♀,

BMNH). Orizaba Mexico Salle Coll, 1 ex (♂, BMNH). MEXICO: Veracruz, Xalapa, Instituto de Ecologia area La Briones 29-XI-94 Quercus /coffee savanna Col. Purrington & C.Drake, 1 ex (♀, OSUC). All other specimens labeled “ Mexico ” or some variant thereof, or without locality information .

Diagnosis. Diceroderes mexicanus can be separated from all other known members of the genus based on the following character combination: Frons with low supraorbital costae; elytra in lateral view nearly straight from base to near apex then sharply declivous; prosternal process raised between coxae, with apical projection; elytra not or weakly depressed near scutellum; tubercles not clothed in micro-pubescence, tubercle apices glabrous and lustrous; males without apical spine on tibia.

Redescription. Male. Length 7.2–8.7 mm, width 3.8–4.4 mm (n = 13 specimens). Color ferruginous to black. Head: Frons densely foveate, denser anteriorly, with low supraorbital ridge or tubercle, posteriorly with weak transverse impression or nearly confluent foveae; vertex raised above frons and densely foveate; frontoclypeal suture deeply and broadly impressed; clypeus densely foveate, tubercles absent or rarely with small tubercles, anterior margin slightly rounded, with slightly raised lip; gena between eye and clypeus raised and densely foveate; faint impression present around eye from gena to apex. Eye elongate oval to slightly reniform, approximately 6 facets across; large U-shaped lobe present behind eye, lobe densely foveate. Labrum without transverse medial ridge, semi-erect golden setae present on anterior half, margin rounded with setae along edges of vertical surface; mandible bifid at apex, dorsal and lateral surfaces smooth; mentum trapezoidal, rugofoveate with mix of long and short straight golden setae, widest at anterior margin, faint medial longitudinal ridge present or absent; submentum small, as wide or wider than basal margin of mentum, triangular to pentagonal. Antennomeres 9 and 10 subequal in size, antennomere 11 smaller than preceding segments and weakly asymmetrical; antennomere 3 approximately 1.4X length of antennomere 4, antennomeres 4–8 subequal in length. Prothorax: Pronotal disc almost flat, widest near middle; moderately to densely foveate, with medial longitudinal region impunctate and tuberculate, each tubercle clothed in decumbent setae curved towards apex of tubercle, apex smooth, rounded, and glabrous, occasionally with visible micropit; discal tubercles randomly distributed except 2 submedial patches of nearly confluent tubercles and 2 longitudinal ridges running from outer base of horns to near basal margin bearing nearly confluent tubercles; anterior half of pronotum bearing 2 sublateral anteriorly directed horns, horns divergent near base then curved towards midline, dorsal and outer surfaces densely tuberculate, ventral and inner surfaces densely foveate, apices slightly recurved; pronotum densely tuberculate laterally from horn to margin, lateral costa absent, lateral margin with row of regularly spaced tubercles, anterior apices slightly produced and acute, posterior apices acute, not projecting; anterior margin straight, with transverse costa running entire length, merging with longitudinal costae on underside of horns; posterior margin slightly bisinuate with medial emargination receiving scutellum. Hypomeron moderately foveate, each fovea with 1 decumbent setae arising from edge. Prosternum anterior to coxa approximately as long as coxal cavity, densely foveate, each fovea with relatively long, decumbent golden seta; prosternal process raised between coxa, medially impressed, apex subacute, with small, recurved process, and projecting behind coxa. Pterothorax: Dorsal outline oval, widest near or slightly behind middle. Elytron dorsally nearly flat to slightly concave, sharply sloping and tapering caudad; stria weakly indicated by irregular rows of fovea, interstria with tubercles and somewhat regularly spaced minute decumbent scale-like setae; each elytral disc with either 2 low, longitudinal, densely tuberculate costae or costae near suture coalesced into 2 separate strongly elevated tuberculate costae, 1 anterior, 1 posterior, and costa furthest from midline irregularly broken and confused; lateral portion of elytron between costae and poorly defined pseudepipleural margin densely tuberculate; pseudepipleura regularly, moderately foveate, lacking tubercles; ventral margin of epiplura with deep groove for reception of abdominal ventrites 3–5. Scutellum with minute decumbent scale-like setae, subtriangular, posterior portion V-shaped, dorsal margin rounded and extending past elytral base, ∼ 1.4X as wide as long. Mesosternum short, anteriorly weakly emarginate behind prosternal process, mesocoxal cavities open. Metasternum short, separating meso- and metacoxal cavities by less than mesocoxal cavity length. All visible ventrites on the pterothorax densely foveate, each fovea with golden seta. Legs: Femora lacking spines or other protrusions, densely shallowly punctate, punctures fine and almost completely obscured by pruinescence, each with 1 decumbent seta; tibia without callosities, clothed in decumbent setae set in fine punctures, inner surface with longer spine-like setae, inner apical margin with 2 distinct socketed spurs, apical spine between spurs absent; distal tarsomere length equal to or greater than length of combined preceding segments, with sparse golden setae, venter of all other tarsomeres clothed with dense long golden setae. Abdomen: Visible ventrites densely finely punctate medially, each puncture with 1 decumbent seta, relatively clean of pruinescence, lateral margins moderately setose, fine punctures often obscured by pruinescence; abdominal intercoxal process broad, with submarginal impression, anterior margin rounded; intersegmental membranes concealed, connection between ventrites 3–5 deeply medially depressed; ventrite 5 lacking submarginal groove; abdominal defensive reservoirs present; sternite 8 weakly sclerotized and setose, deeply medially emarginate, emargination V-shaped; aedeagus with parameres fused, slightly longer than basal piece, dorsally flattened and nearly parallel sided until apical fifth of length, apical fifth sharply acuminate, partially dehisced at tip and weakly curved ventrad ( Figs. 3–4 ).

Female. Similar to male, except with shorter, stouter pronotal horns, horns curved towards midline but not recurved at apex ( Figs. 16–17 , 21–22 ).

Variation. Specimens can be roughly sorted into two morphs based on elytral sculpturing. The lectotype and paralectotype represent morph one ( Figs. 13–17 ). A male ( Figs. 19–20 ) and female ( Figs. 21–22 ) of morph two are shown for comparison. However, the two morphs overlap in distribution and a number of specimens are difficult to place. Male genitalia and all other characters examined, other than elytral sculpturing, support maintaining them as unnamed variants of D. mexicanus . One potential cause for the observed variation may be seasonality. Specimens with relatively regular elytral costae, such as the type specimens, were collected from June to mid-August. Specimens with elytral costae broken into distinct separate regions, morph two, were collected from mid-August to December.

Distribution. Mexico: Hidalgo, Puebla, Veracruz ( Fig. 23 ).

Figures

Figs. 3–12. Diceroderes species, aedeagi, dorsal and lateral views. 3–4) D. mexicanus, TB# 14740; 5–6) D. cusucoensis, holotype, TB# 14688; 7–8) D. ocozocoautlaensis, holotype, TB# 14689; 9–10) D. skelleyi, holotype, TB# 13105; 11–12) D. subtriplehorni, holotype, TB# 13109.

Figs. 13–15. Diceroderes mexicanus, lectotype (male). 13) Dorsal habitus; 14) Lateral habitus; 15) Labels.

Figs. 16–18. Diceroderes mexicanus, paralectotype (female). 16) Dorsal habitus; 17) Lateral habitus; 18) Labels.

Figs. 19–20. Diceroderes mexicanus, morph two specimen (male), TB# 14740. 19) Dorsal habitus; 20) Lateral habitus.

Figs. 21–22. Diceroderes mexicanus, morph two specimen (female), TB# 14795. 21) Dorsal habitus; 22) Lateral habitus.

Fig. 23. Diceroderes species, distribution map. Triangles = D. mexicanus, white triangles are for morph one, gray/blue triangles for morph two. Stars = D. cusucoensis. Squares = D. ocozocoautlaensis. Diamonds = D. skelleyi. Circles = D. subtriplehorni.