Mecodema regulus Britton, 1964

Seldon, David S. & Leschen, Richard A. B., 2011, Revision of the Mecodema curvidens species group (Coleoptera: Carabidae: Broscini), Zootaxa 2829, pp. 1-45 : 38-39

Mecodema regulus Britton, 1964 (redescription)

Figures: 5, 10c, 20a, 21a, 25a.

Mecodema regulus Britton, 1964: 526 .

Diagnosis. Head, body broad and flattened. Clypeus with a single or 2 lateral punctures on each side, bearing 1 or 2 setae. Prothoracic carina broad, crenulation may or may not be present, extended to beyond anterior angle. Pronotum fovea broad and deep. Elytral striae with regularly distributed, small asetose punctures. Setose punctures on 3rd, 4th and 5th ventrites absent. Apical portion of aedeagus symmetrically rounded with a strong twist to right of vertical. Dorso-apical portion of central spicule, greatly expanded. Basal lobe of left paramere rectangular, arm and apical lobe relatively large, and with setation along apical ¾ of ventral edge.

Description. Length 20–26 mm. Colour black. Head, body broad and flattened. Microsculpture of frons and vertex absent. Vertexal groove narrow, defined entire length with V-shape at midpoint. Form of microsculpture on anterior area of clypeus, poorly defined. Clypeus with a single or 2 setose punctures on each side bearing 1 or 2 setae. Form of lobes of the mentum, rounded. Submentum constriction, narrow with greater than 6 setae. Prothoracic carina broad, crenulation may be present and extended to beyond anterior angle. Pronotum broad and flattened, posterior lateral sinuation highly angled inward. Pronotal fovea broad and deep, rugose microsculpture absent laterally on pronotal disc. Elytra broad and flattened, striae with small regularly distributed asetose punctures, intervals slightly convex. A single setose puncture present on mesocoxa and absent on metacoxa. Setose punctures on 3rd, 4th and 5th ventrites absent. Apical portion of aedeagus symmetrically rounded with a strong twist to right of vertical axis. Dorso-apical portion of central spicule, greatly expanded. Left paramere basal lobe rectangular, arm and apical lobe relatively large, with setation along apical ¾ of ventral edge.

Comments. This species was described by Britton (1964) and the name is based on seven specimens in good condition. Mecodema regulus is found on all of the large islands in the Three Kings group. As with other insect species, this carabid shows similarities in morphology to the Mecodema found at Cape Reinga ( M. tenaki ) and the Poor Knights ( M. ponaiti ). Britton (1964) had described this species with a subspecific name “mihi” which was unnecessary since there was no other subspecies included in the species (see Larochelle and Larivière 2001).

Distribution. New Zealand, Northland (ND), Three Kings Islands (only).

Holotype: ( NZAC) card mounted Type (round label with red border glued to card) / Great Island Three Kings 1- 3.1.63 E.S. Gourlay [hw] / under large stones in forest Ca. 200’ [hw] / HOLOTYPE 3 Mecodema regulus mihi [hw] / E.B. Britton det. 1964 [date hw] / NZ Arthropod Collection NZAC 04011202.

Paratypes: 2, card mounted, Para-type (round label with yellow border glued to card) / Great Island Three Kings 1-3-1-63 E. S. Gourley [hw] / Brit. Mus. 1964-32. [32 is hw] / PARATYPE Ƥ Mecodema regulus mihi E. B. Britton det. 1964 [date hw] ( NZAC); 2́ card mounted, Para-type (round label with yellow border glued to card) / Great Island, Three Kings, 1- 3.1.63, E.S. Gourlay [hw] / PARATYPE Ƥ Mecodema regulus mihi, E.B. Britton det. 1964 [hw] / E.S. Gourlay Acc. 1970 Ent. Div. ( NZAC); 1, card mounted (right antennae broken but pieces glued to card, left mesoleg tarsal segments missing), Para-type (round label with yellow border glued to card) / Great Island, Three Kings, 1- 3.1.63, E.S. Gourlay [hw] / PARATYPE Ƥ Mecodema regulus mihi, E.B. Britton det. 1964 [hw] / J.I. Townsend Collection / NZ Arthropod Collection NZAC 04009614 ( NZAC).

Other material examined: ND: 24, Great Is. 1970 G. Ramsey ( NZAC); 1, Great Is. 1970 J.C. Watt ( NZAC); 1, Great Is. 1983 J.C. Watt ( NZAC); 4, Great Is. 1996 J.W.M. Marris ( LUNZ); 2, Great Is. Tasman Valley 1996 J.W.M. Marris ( LUNZ); 8, Great Is. Lighthouse Bush 1996 J.W.M. Marris ( LUNZ); 2, Great Is. South East Bay 1996 J.W.M. Marris ( LUNZ).