Megalostomis juanenrique, Agrain, Federico A., 2014

Agrain, Federico A., 2014, An interactive multi-entry key to the species of Megalostomis Chevrolat, with description of a new species from Paraguay (Chrysomelidae, Cryptocephalinae), ZooKeys 425, pp. 59-69 : 61-64

Taxon classification Animalia Coleoptera Chrysomelidae

Megalostomis juanenrique sp. n. Figs 1-3

Type locality.

PARAGUAY, San Pedro: Cororō (23.439011°S, 56.501807°W).

Type specimens.

Holotype: male, pinned. Original labels: "White label (handwritten): Paraguay-San Pe / dro-Córoro / M. Viana XI_1983_, Blue label (printed): ex Coleccion/ M. VIANA/ ARG 006244, White label (printed): Coleccion / J. E. BARRIGA / CHILE 067786". Red label (printed): Megalostomis juanenrique sp. n. / Holotype/ Des. Agrain F. A. 2014. IADIZA. Allotype: female, pinned, with genitalia in a separate microvial. Original labels: "White label (handwritten): Paraguay.S.P./ Córoro / M. Viana 1979, Blue label (printed): ex Coleccion/ M. VIANA/ ARG 006337, White label (printed): Coleccion / J. E. BARRIGA / CHILE 067005". Red label (printed): Megalostomis juanenrique sp. n. / Allotype/ Des. Agrain F. A. 2014. IADIZA. Paratype: male, pinned, with genitalia in a separate microvial. Original labels: "White label (printed): PARAGUAY/ Córoro / dic 1983/ leg. M. Viana, White label (printed): Coleccion / J. E. BARRIGA / CHILE 138773". INBP. Paratype: male, pinned. Original labels: "White label (handwritten): Paraguay-S P/ Córoro / M. Viana _1976, Blue label (printed): ex Coleccion/ M. VIANA/ ARG 006362, White label (printed): Coleccion / J. E. BARRIGA / CHILE 063063". MACN. Paratype: male, pinned. Original labels: "White label (handwritten): Paraguay-San/ Pedro-Córoro / XI_1985_ M. Viana, Blue label (printed): ex Coleccion/ M. VIANA/ ARG 006238, White label (printed): Coleccion / J. E. BARRIGA / CHILE 069889". JEBC. Paratype: male, pinned, with genitalia in a separate microvial. Original labels: "White label (handwritten): Paraguay. S.P./ Córoro / M. Viana 1976, Blue label (printed): ex Coleccion/ M. VIANA/ ARG 006406, White label (printed): Coleccion / J. E. BARRIGA / CHILE 067050". JEBC. Paratype: male, pinned, with genitalia in a separate microvial. Original labels: "White label (handwritten): Paraguay. S.P./ Córoro / M. Viana 1976, Blue label (printed): ex Coleccion/ M. VIANA/ ARG 006270, White label (printed): Coleccion / J. E. BARRIGA / CHILE 057918". JEBC. All paratypes with my label: Red label (printed): Megalostomis juanenrique sp. n./ Paratype/ Des. Agrain F. A. 2014.

Diagnosis.

This new species belongs to the Megalostomis grossa species group as defined by Agrain and Roig-Juñent (2011). Characters of this species group exhibited by this species are: uniform antennal coloration, presence of a longitudinal carina at interocular space, and pronotal disc pilosity limited to or denser at its margins; even if this species shares some characters with its relatives (e.g. the hypertrophied eye stalk with Megalostomis grandis (Forsberg), it can be easily separated from this and other related species by several characters: male mandibles exceeding length of clypeus, head wider than long, subrectangular pronotal disc longer than high, with its lateral margins visible from above, central dorsal plate of kotpresse (female) with three arms, apical margin of dorsal plate of aedeagus straight, among others. As a rule, for this genus, the best way to identify the females (without dissecting them) is by comparing the coloration pattern with their respective males.

Body length.

11.3-12.5 mm, width: 6.3-7.2 mm.

Male

(Figs 1 A–B, D, 2). Coloration pattern: elytra reddish, with three interspaced sub-transverse black bands, all reaching lateral margin of elytra, basal band reaching humeral carina, and apical band reaching elytral apex. Head: anterior surface smooth, with central protuberance at upper region of clypeus, mostly glabrous with disperse pubescence; inter-ocular space with thin longitudinal carina, with a pair of slightly depressed sub-adjacent areas on either side; internal margin of eyes with strongly marked carina, posterior side of eye with salient post-ocular protuberance, next to a marked furrow. Mandibles asymmetric; apex of mandibles with a series of peaks (molariform area) surrounding a depressed area that fits into the right mandible; right mandible curved inward, mandibular apex with a very sharp tooth on its underside; left mandible straight, with sharp bifurcated teeth; with common intra-specific variation in size among examined series. Clypeal margin, straight, without auricular appendix. Antennae: as long as pronotum, black; scape robust; serrate beyond fourth antennomere, eleventh antennomere with two marginal excavations that delimit central lobe. Thorax: pronotal disc: longer than high, sub-rectangular, lateral margins visible from above; posterior projection short; median lateral region with slight transverse constriction; punctation weak and regular; pronotal disc pilosity limited to its margins; scutellum wider than long, with posterior margins curved, covered with white dense pubescence. Elytra: apical margin projected, surpassing pygidium; elytral humeral region wider than pronotal base, gradually narrowing toward apex; diffuse punctation, denser than that of pronotum; elytral margin narrow, enlarged in humeral region; humeral carina rounded, apex with transverse mark. Genitalia: (Fig. 2 A–C) apex of dorsal plate of median lobe as wide as its base, with anterior margin straight; lateral arms of median lobe short, with setae; dorsal sclerite of internal sac (not everted) upward-directed, forming a wing-shaped structure in dorsal view; ejaculatory guide with ventral keel; sperm transfer structure with campanulate sclerite.

Female

(Figs 1C, E, 3). Coloration pattern: same as male. Head: smaller than that of male; mandibles compact and short. Antennae: same as male, but shorter than pronotum (with smaller antennomeres). Thorax: pronotum with sides slightly more curved than in male. Abdomen: sternites same as in male, fifth sternite excavate. Pygidium: with apical excavation and, apical transverse depressed area. Rectal sclerites: dorsal rectal sclerites (Fig. 3A) represented only by dorsal (subquadrate) apodemes, and central dorsal plate. Central dorsal plate (Fig. 3B) subquadrangular with three arms; ventral rectal sclerites with very short apodemes. Spermathecal capsule: (Fig. 3C) U-shaped, distal part more than 2 × longer than proximal part, proximal part longer than base; angle formed between basal and apical regions of spermathecal capsule less than 45°; apex of spermathecal capsule long, with sharp tip. Eighth sternite with central tooth (Fig. 3D).

Etymology.

Specific name is treated as a noun in apposition ( ICZN 1999, Art. 34.2.1), it is dedicated to the distinguished Chilean coleopterist Agr. Eng. Juan Enrique Barriga-Tuñon, who generously received me in his outstanding insect collection.