Mecodema atuanui Seldon & Buckley 2019, sp. n.
Creators: name: Seldon, David S.
name: Buckley, Thomas R.
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Mecodema
Mecodema atuanui

description: Mecodema atuanui sp. n.
Figures 6C and 21.
Diagnosis: Distinguished from other North Island Mecodema species by having: 1, a lobed labrum; 2, vertexal groove defined by punctures along the entire length; 3, elytral intervals 3 and 5 significantly broadened than other intervals; 4, the distinctively narrow width of the apical portion of the penis lobe (Fig. 21 PL).
Description: Length 24.9 mm, pronotal width 6.7 mm, elytral width 7.9 mm. Colour of entire body matte black, except coxae and legs dark reddish-brown.
Head: Broad and flat (Fig. 14A). Vertex with very faint wrinkles; vertexal groove shallow, broadened laterally with several punctures present along groove; small supraorbital puncture bearing 2–3 setae (specimen damaged); 4 well-defined supraorbital grooves form a ridge anterad eye, grooves extended to lateral margins of frons; frons (Fig. 9) with a ridge medially, a broad and shallow depression each side of midline extended to tentorial pits; frontoclypeal suture very narrow, cuticle humped anterad and posterad suture, tentorial pits small; anterior area of clypeus with 3 narrow grooves; clypeus with 1 large setose puncture each side bearing 2 setae. Labrum lobate, anterior edge distinctly emarginate medially with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes rounded (Fig. 12F), median process short and broad, slightly angled upward (15°), indentation notched (Fig. 12D); setose punctures absent. Submentum sclerite constriction broad with 6 regularly spaced setae. Stipes with 2 basal setae. Gula (Fig. 8) pits small, suture well-defined, anterior area of gula slightly convex, posterior flat and smooth. Gena with fine wrinkles forming an isodiametric pattern across entire area.
Prothorax: Prothoracic carina (Fig. 11) broad in anterior ⅓, narrowed posterad, slightly crenulated with 7–10 setae each side, extended beyond anterior angle; posterior lateral sinuation evidently carinate, parallel; pronotal lateral margin broad, anterior lateral margin angled backward, deflected laterally, overall shape cordate; midline well-defined, posterior medial diamond-shaped impression present, disc with fine transverse wrinkles; pronotal foveae shallow and narrow; anterior edge and posterior edge straight (Fig. 21). Prosternum flat and smooth; proepisternum obsolescently micropunctate. Procoxal setae absent; protibia distally expanded and shovel-like (Fig. 10B).
Elytra: Narrow and medially flattened; humeral angle subangulate (Fig. 6C), basal margin moderately curved and bevelled to base laterally, interval 1 extended to scutellum, all other intervals and striae truncated at margin; lateral carina narrow the entire length, broadened apically, extended to humeral angle; humerus with 3 setose punctures proximate the angle, 4 th double-spaced posterad (Fig. 21); suture defined but no more so than striae; striae 1–6 with asetose punctures poorly defined, striae 7 and 8 with asetose punctures visible in posterior ½ only; intervals 1–4 weakly convex, convexity of intervals 5–8 increased laterally; interval microsculpture present as short fine transverse lines radiating from asetose punctures, increased in intensity laterally; intervals 3 and 5 significantly broader than other intervals; 7 th strial setal pattern (Fig. 1) with 3 setae in anterior ½ and 3 setae in posterior ½, a relatively large space between setose punctures medially (Fig. 21), setose punctures small.
Ventral surface: Mesepisternum without microsculpture; metepisternum (Fig. 2) with finely lineate proximate carina; setose punctures present on mesocoxae (1) and on metacoxae (2). Abdominal ventrites 1–5 finely lineate; ventrites 3–5 with 1 setose puncture each side of midline; ventrite 6 setae present: ♂ with 1 seta each side situated at postero-lateral angle, apical edge straight (no ♀ specimen available); lateral foveae on ventrites absent. Anterior metaventrite process (Fig. 2) a short triangle with a very well-defined broad carina the entire length.
Male genitalia: (both parameres have lost parts of the setal fringes).
Apical portion of penis lobe asymmetrically hooked, short apical portion with moderate deflection to right of vertical axis (VV) (Fig. 15B), ventral edge of penis lobe straight (VV); apex width entirely narrow, ventral process sharply angled to a rounded point (Fig. 21 PL), the point is slightly forward of perpendicular (Fig. 3), apex curved upward to form the dorsal process that is very rounded (Fig. 21 PL), broad at base, hook posterad perpendicular; shaft of penis lobe narrow, slightly broadened apically, overall length of penis lobe moderately curved ventrally (LV) (Fig. 16B). Structures of the endophallus (Fig. 4): lateral form of the apex of the central spicule flattened; dorsal form of the apex of the central spicule greatly expanded with a projection; setal (scales) coverage of apical plate is extensive (76–100%); left setose flange large; right setose flange absent. Left paramere basal lobe rectangular with an anterior hump forming a moderate (45°) slope to arm; arm narrow and broadened to form terminal lobe (Fig. 21 LP); setae extended to basal lobe-arm junction (apical ⅓) with tuft of short setae at apex of lobe; ventral edge relatively straight. Right paramere broadly triangular but not as high at apex (Fig. 21 RP), double-row of long setae extended along apical ½ of ventral edge; apical ⅓ of right paramere inwardly curved in front of penis lobe posterad apical hook.
Female genitalia: no female specimen available.
Comments: Mecodema atuanui is more closely related to M. spiniferum (Waitakere Ranges), than species to the north (M. rusticulus) or east (M. dunnorum).
Distribution: New Zealand, North Island, Auckland region, Kaipara Harbour Coast (south of the Hoteo River), Mt Auckland (Atuanui).
Holotype: AMNZ male labelled. NEW ZEALAND, AK, Atuanui (Mt Auckland), pitfall D13, Jan 2002, A. Warren / HOLOTYPE Mecodema atuanui n. sp. design. DS Seldon, TR Buckley 2018 [red label] / AMNZ 57759 [green label].
Etymology: The species is named after the only known locality, Atuanui (Mt Auckland), where a single specimen has been collected.
description: Published as part of Seldon, David S. & Buckley, Thomas R., 2019, The genus Mecodema Blanchard 1853 (Coleoptera: Carabidae: Broscini) from the North Island, New Zealand, pp. 1-148 in Zootaxa 4598 (1) on pages 32-34, DOI: 10.11646/zootaxa.4598.1.1, http://zenodo.org/record/2668063