Mecodema temata, Seldon & Buckley, 2019

Seldon, David S. & Buckley, Thomas R., 2019, The genus Mecodema Blanchard 1853 (Coleoptera: Carabidae: Broscini) from the North Island, New Zealand, Zootaxa 4598 (1), pp. 1-148 : 112-114

Mecodema temata sp. n.

Figure 55 .

Diagnosis: Differing from other North Island Mecodema species by having: 1, 4–8 setae along the prothoracic carina ( curvidens species group); 2, the vertexal groove being defined laterally by a very shallow depression behind the supraorbital puncture; 3, a setose puncture at the anterior junction of elytra intervals 6 and 7; 4, the setal distribution along the ventral edge of the left paramere ( Fig. 55 LP).

Description: Length 16.5–19.5 mm, pronotal width 4.5–5.7 mm, elytral width 5.6–6.5 mm. Colour of entire body glossy black, coxae and legs dark red to black.

Head: Narrow and convex ( Fig. 14D ). Vertex smooth; vertexal groove defined laterally by a very shallow depression behind supraorbital puncture; small supraorbital puncture ( Fig. 9 ) and deep bearing 3–4 setae; 1 shallow supraorbital groove; frons smooth; frontoclypeal suture very narrow, very small tentorial pits; anterior area of clypeus with very shallow depressions (poorly defined); clypeus with 1 small puncture each side bearing 1 seta ( Fig. 55 ). Labrum rounded, anterior edge straight with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes squared ( Fig. 12G ), process long and narrow, upward angle absent, indentation notched ( Fig. 12D ); mentum setae present. Submentum sclerite constriction narrow with 2 setae each side, widely spaced laterally. Stipes with 2 basal setae. Gula pits deep and narrow, suture well-defined, gula flat with very fine transverse lines. Gena ( Fig. 8 ) smooth.

Prothorax: Prothoracic carina ( Fig. 11 ) very narrow the entire length, slightly crenulated (or smooth) with 4–8 setae each side ( Fig. 55 ), extended beyond anterior angle; posterior lateral sinuation indistinctly carinate, slightly angled inward; pronotum narrow and deflected, overall shape squared; midline well-defined, without anterior medial diamond-shaped depression and posterior medial depression, disc with fine transverse lines laterally ( Fig. 55 ); pronotal foveae shallow and narrow; anterior edge inwardly curved, posterior edge straight. Prosternum flat and smooth; proepisternum without microsculpture. Procoxal setae absent; protibia distally expanded and shovellike ( Fig. 10B ).

Elytra: Broad (in relation to pronotum) and deflected; humeral angle anteriorly convergent ( Fig. 6A ); basal margin slightly curved and bevelled to base, interval 1 extended to margin; lateral carina narrow the entire length, extended to humeral angle; humerus with 2 setose punctures; suture well-defined; striae asetose punctures regularly spaced and equal size, all striae well-defined; all intervals moderately convex, interval microsculpture absent; 7 th strial setal ( Fig. 1 ) pattern with 3 setose punctures in anterior ½, 4–5 setose punctures in posterior ½ ( Fig. 55 ), setose punctures large; setose puncture at the anterior junction of intervals 6 and 7.

Ventral surface: Mesepisternum ( Fig. 2 ) and metepisternum without microsculpture; setose punctures present on mesocoxae (1) and metacoxae (1). Abdominal ventrites 1 and 2 finely lineate laterally; ventrites 3–5 with 1 setose puncture present each side of midline; lateral foveae absent; ventrite 6 setae present: ♂ with 1–2 setose punctures each side, apical edge bluntly rounded, (♀ specimen not available). Anterior metaventrite process ( Fig. 2 ) a rounded triangle without a carina.

Male genitalia: Apical portion of penis lobe symmetrically rounded ( Fig. 55 PL) but short and broad, narrowed to a round apex (VV); ventral edge of penis lobe straight (VV/LV). Structures of the endophallus ( Fig. 4 ): lateral form of the apex of the central spicule pointed; dorsal form of the apex of the central spicule short and narrow; setal (scales) coverage of the apical plate sparse (1–25%); size of left setose flange small; size of right setose flange large. Left paramere basal lobe narrowly rectangular, narrowed slightly toward arm, short slope to arm ( Fig. 55 LP); arm long and narrow; terminal lobe very small, indistinct from arm with a small apical tuft of short setae only ( Fig. 55 LP); ventral edge straight. Right paramere long, narrowly rectangular with a double row of long setae extended along apical ¾ of ventral edge ( Fig. 55 RP).

Female genitalia: no female specimen available.

Comments: This species has persisted in a very small wet gully of native scrub and old karaka ( Corynocarpus laevigatus ) trees, which have escaped the fires and deforestation of the region. It is not known whether any other populations of M. temata exist in other areas of Hawke’s Bay.

Distribution: New Zealand, North Island, Hawke’s Bay, Havelock North, Te Mata peak.

Holotype: NZAC male labelled. NEW ZEALAND HB Havelock North, Te Mata Peak, Nature Trail 5 Jan 2016, DS Seldon, J. Tizard / at large, CAR301, S39°41’55.4 E176°54’03.5, 146 m / HOLOTYPE Mecodema temata n. sp. design. DS Seldon, TR Buckley 2018 [red label].

Paratypes: 1♂ [card mounted], 2♂, NEW ZEALAND Havelock North , Te Mata Peak, Nature Trail, by hand, 5 Jan 2016, DS Seldon, J. Tizard ( NZAC) .

Etymology: This species is named after the type locality, Te Mata Peak.

Figures

FIGURE 1. Dorsal view of a Mecodema specimen showing taxonomic structures used in the species descriptions. H =head; P = pronotum; E = elytra; S = striae; I1 = interval 1; A = apex; 7S = 7 th strial setae; HSP = humerus setose puncture; HA = humeral angle; BM = basal margin; P = protibia.

FIGURE 2. Ventral view of a Mecodema specimen showing specific morphological structures, excluding taxonomic structures indicated in detail figures, used in the species descriptions. ƑLF = ventrite lateral foveae; ƑSP = ventrite setose punctures; MTC = metacoxa; MTƑP = metaventrite process; MSC = mesocoxa; PC = procoxa; PS = prosternum; G = gena; PES = proepisternum; MSE = mesepisternum; MTE = metepisternum; Ƒ1–Ƒ6 = ventrites 1-6 (ventrites 1-3 may be fused); M = midline (dashed line, not a taxonomic structure).

FIGURE 4. An Environmental Scanning Electron Microscope (ESEM) photograph of the four main structures of the apical plate of the endophallus within the penis lobe. This is an example from Mecodema haunoho showing the central spicule (c.s), left (l.s.f) and the right setose flange (r.s.f), and microtrichial field (m.f). These structures are variable among species but within a species, they are very consistent, even over distant geographical ranges. The microtrichial field can be covered in flattened scales as in photo above, or with elongated setae-like scales.

FIGURE 6. Detail of the three different forms of the elytral humeral angle: (A) = anteriorly convergent (M. parataiko), (B) = evenly convex (M. oconnori), (C) = subangulate (M. atuanui).

FIGURE 8. Detail of the ventral head with the taxonomic structures used in the species descriptions. SBMS = submentum setae; SBM = submentum sclerite; ML = mentum lobe; MP = mentum process (with indentation); MPW = mentum process width; SBS = stipes basal setae; MPL = mentum process length; MPS = mentum process setae; SBMC = submentum sclerite constriction; GP = gula pits; GS = gula suture.

FIGURE 9. Dorsal view of head with detail of the morphological structures used in the species descriptions. Ƒ = vertex; SPS = supraorbital puncture setae; SP = supraorbital puncture; F = frons area; FCS = frontoclypeal suture; C = clypeus; M = mandible; LS = labrum setae; L = labrum; ACM = anterior clypeal microsculpture; CSP = clypeal setose puncture; TP = tentorial pit; SG = supraorbital grooves; E = eye; ƑG = vertexal groove.

FIGURE 10. The protibia form is a character used mainly to determine between genera, except for one species in Mecodema where the difference between (A) greatly distally expanded (M. antarctica) and (B) expanded distally (all other Mecodema species) is used.

FIGURE 11. Detail of pronotum showing the taxonomic structures used in the species descriptions. PPC = posterior pronotum constriction; PS = pronotal setae; PAA = pronotum anterior angle; AE = anterior edge; PC = pronotal carina; ML = midline; PF= pronotal foveae; PPS = pronotum posterior sinuation; PE = posterior edge.

FIGURE 12. Ventral view of the mentum with a number of different character states. Illustrations A–D are the different forms of the indentation in the apex of the median process: (A) distinctly indentate (M. manaia); (B) moderately indentate (M. pluto); (C) slightly indentate (M. infimate); (D) indentation notched (M. parataiko). Illustrations E–G are the three general forms (i.e., hashed lines) of the mentum lobes: (E) triangular; (F) rounded; (G) squared.

FIGURE 14. Diagrammatic cross sections that represent the width and convexity of head or deflection of pronotum (frontal view): (A) broad and flat; (B) broad and convex; (C) narrow and flat; (D) narrow and convex.

FIGURE 55. Mecodema temata plate with half habitus (left) and the three (detached) structures of the male aedeagus: the right (RP) and left parameres (LP), plus the penis lobe (PL). The bottom scale bar is the width across the widest point of the pronotum of the specimen used for this habitus and top scale bar equates to the half the length of the penis lobe.