Mizotrechus minutus, Erwin, 2011

Erwin, Terry L., 2011, Rainforest understory beetles of the Neotropics, Mizotrechus Bates 1872, a generic synopsis with descriptions of new species from Central America and northern South America (Coleoptera, Carabidae, Perigonini), ZooKeys 145, pp. 79-128 : 98-99

Minute trough beetle Mizotrechus minutus sp. n. Figs 14 19 34 40

Holotype.

GUYANE, Saül, Commune de Saül, Belvédère de Saül, 283-325 m, 3.6223°N, 53.2159°W, 10 December 2010 (S Brule, PH Dalens, & E Poirier)(NMNH: ADP124966, male).

Derivation of specific epithet.

The epithet “minutus” is a Latin adjective that adequately describes this species with very small adults.

Proposed English vernacular name.

Minute trough beetle.

Diagnosis.

With the attributes of the genus as described above and very small sized for the genus as it is presently understood; adults have castaneous integument, except anterior parts of mandible, baso-lateral corner of labrum, and clypeal suture piceous. Frons with rugae nearly effaced, punctulate. Occiput punctulate. Pronotum quadrate with lateral margins shallowly emarginated; base nearly smooth. Elytra broad and short, slightly wider than the width of pronotum across anterior third, and with 8 well-impressed punctate interneurs; margins behind humeri not serrulate.

Description.

( Figs 14 , 19 , 34 ). Size: See Appendix 1. Very small, ABL = 4.4-4.6 mm, SBL = 3.77-3.88 mm, TW = 1.49-1.58 mm. Color: see diagnosis, above. Luster: Head, pronotum, elytra, and legs shiny; microsculpture effaced. Head: Labrum quadrate and apico-medially emarginate. Eye moderately large, moderately convex. Gena moderately long, straight. Frons, occiput, and genae glabrous. Prothorax: Broad, narrowed slightly toward base, margin slightly explanate to hind angle, angle about right, not dentate; surface punctulate, punctures widespread, glabrous. Pterothorax: Elytron moderately convex, intervals slightly convex, interneurs striato- punctate, apex moderately oblique and straight, sutural apex narrowly rounded. Metasternum sparsely setiferous in male. Legs: Normal in both sexes; foreleg femur unmodified ( Fig. 19 ); trochanter narrowly rounded. Abdomen: Abdominal sterna moderately setiferous; sternum IV of male with narrow and dense patch of decumbent setae. Male genitalia: Median lobe ( Fig. 34 ) elongate and narrow with ostium moderately elongate, over half the length of the median lobe; apex with a long narrow distal end, straight in lateral aspect and narrowly rounded, ventral margin proximal to apex straight; endophallus with complexly folded tracheal fields; phallobase hooded, opening more or less 15 degrees off axis of shaft. Parameres large, left a third longer than the right, both broadly rounded, asetose. Female genitalia: Not investigated; however, it is likely similar to that illustrated on Plate 11 .

Dispersal potential.

These beetles are macropterous and capable of flight. They are moderately swift and agile runners.

Way of life.

The adult holotype was collected in a flight intercept trap in the rainforest understory. Adults are active in December, at the end of the dry season.

Other specimens examined.

Paratypes: Guyane, Saut Pararé, Arataie River, Nouragues Field Station, 51 m, 4.0378°N, 52.6725°W, 11 December 2009 (S Brule, PH Dalens, & E Poirier)(NMNH: ADP124902, male), Saül, Commune de Saül, Belvédère de Saül, 283-325 m, 3.6223°N, 53.2159°W, 10 December 2010 (S Brule, PH Dalens, & E Poirier)(NMNH: ADP124920, female).

Geographic distribution.

( Fig. 40 ). This species is currently known only from two localities in the lowlands of Guyane.

Figures

Plate 4. Digital Photo-illustrations, habitus, dorsal aspect: 13 Mizotrechus marielaforetae sp. n., dorsal aspect, ABL = 5.9 mm, male paratype, ADP 127183, type locality. 14 Mizotrechus minutus sp. n., ABL = 4.4 mm, female paratype, ADP 124920; Guyane, Commune de Sauel, Belvedere de Sauel. 15 Mizotrechus neblinensis sp. n., dorsal aspect, ABL = 6.9 mm, female holotype, ADP 124944; type locality. 16 Mizotrechus novemstriatus Bates 1872, ABL = 7.2 mm, female lectotype, ADP 127163; type locality.

Plate 6. Digital Photo-illustrations, anterior femur, ventral aspect: 19 Mizotrechus minutus sp. n., ADP 124966; type locality. 20 Mizotrechus dalensi sp. n., ADP 124896; type locality. 21 Mizotrechus chontalesensis sp. n., ADP 127181; type locality. 22 Mizotrechus edithpiafae sp. n., ADP 124948; type locality. 23 Mizotrechus brulei sp. n., ADP 129205; type locality. 24 Mizotrechus gorgona. sp. n., ADP 128622; type locality.

Plate 10. Digital Photo-illustration, male genitalia, median lobe, left lateral, dorsal, and right lateral aspects: 34 Mizotrechus minutus sp. n., ADP 124902; type locality. 35 Mizotrechus neblinensis sp. n., ADP 124944; type locality. 36 Mizotrechus poirieri sp. n., ADP 124888; type locality.

Plate 11. Figure 37. Digital Photo-illustration, female genitalia: Mizotrechus dalensi sp. n., ADP 127161; Petite Montague Tortue, Guyane. A. Dorsal aspect. Legend, bc, bursa copulatrix; co, common oviduct; sg, spermathecal gland; sgd, spermathecal gland duct; sp, spermatheca. dorsal aspect; vc, villous canal; lt, laterotergite; gc 1, gonocoxite 1; gc 2, gonocoxite 2. B. Gonocoxite 2, dorsal aspect: Legend, b, base of gonocoxite 2; bl, blade of gonocoxite 2; des, dorsal ensiform seta; ves, ventral ensiform setae.

Figure 40. Distribution symbol map for known localities of Mizotrechus batesi, Mizotrechus bellorum, Mizotrechus belvedere, Mizotrechus brulei, Mizotrechus dalensi, Mizotrechus grossus, Mizotrechus marielaforetae, Mizotrechus minutus, Mizotrechus poirieri, Mizotrechus neblinensis, spp. n.