Mecodema undecimus, 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 : 128-131

Mecodema undecimus sp. n.

Figure 62 .

Diagnosis: Distinguished from other North Island Mecodema species by having: 1, vertexal groove very distinctly broad entire length, formed by ridge posterad frons; 2, a unique shape of the apical portion of the penis lobe ( Fig. 62 PL).

Description: Length 24–29 mm, pronotal width 5–7 mm, elytral width 6–8 mm. Colour of entire body matte to glossy black, coxae dark reddish-brown.

Head: Broad and deflected laterally ( Fig. 14B ). Vertex smooth ( Fig. 62 ); vertexal groove very distinctly broad entire length, formed by ridge posterad frons, may be micropunctate laterally; small supraorbital puncture bearing 4–5 setae (may be another setose puncture near orbital puncture); 2–3 indistinct to shallow supraorbital grooves; frons with rugose wrinkles antero-laterally, a large and shallow depression each side of midline; frontoclypeal suture ( Fig. 9 ) and tentorial pits indistinct; anterior area of clypeus with grooves, 1 setose puncture each side bearing 2 setae and 1 medial setose puncture bearing 1–2 setae ( Fig. 62 ). Labrum lobate, anterior edge medially emarginated with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes rounded ( Fig. 12F ), median process broad and short, upward angle absent, moderately indentate ( Fig. 12B ); mentum setae variably absent or present. Submentum sclerite constriction broad with 6 evenly-spaced setae. Stipes with 2 basal setae. Gula pits ( Fig. 8 ) small, suture indistinct, gula flat and smooth. Gena with very fine, transverse lines forming an isodiametric pattern laterally.

Prothorax: Prothoracic carina broad the entire length, crenulations absent with 9–12 setae each side ( Fig. 62 ), extended beyond anterior angle; posterior lateral sinuation indistinctly carinate, parallel to slightly angled inward; pronotum broad and deflected laterally, overall shape triangular; midline poorly impressed, anterior medial triangular impression and posterior medial diamond-shaped impression present, disc with fine transverse lines laterally ( Fig. 62 ); pronotal foveae broad and shallow; anterior edge inwardly curved, posterior edge straight. Prosternum flat and smooth; proepisternum without microsculpture. Procoxal setae absent; protibia distally expanded and shovel-like ( Fig. 10B ).

Elytra: Narrow and moderately deflected; humeral angle evenly convex ( Fig. 6B ); basal margin moderately curved and bevelled to base, interval 1 extended to margin; lateral carina narrow anterior and medial ⅓, broadened in posterior ⅓, extended to anterior angle; humerus with 2–3 setose punctures high in angle ( Fig. 62 ); suture slightly impressed; striae with small, regularly spaced, asetose punctures, striae 1–6 punctures may be obsolescent; intervals 1–6 flat (or weakly convex), intervals 7–9 moderately convex; interval microsculpture absent; 7 th strial setal pattern with 2–3 setose punctures in anterior ½, 4–5 setose punctures in posterior ½ ( Fig. 62 ), setose punctures large.

Ventral surface: Mesepisternum and metepisternum without microsculpture; setose punctures present on mesocoxae (2) and metacoxae (2). All abdominal ventrites ( Fig. 2 ) finely lineate laterally; ventrites 3–5 ventrites with 1 setose puncture each side of midline; ventrite 6 setae ( Fig. 2 ) present: ♂ male with 1 setose puncture at junction of straight apical edge and curve anterad, ♀ with 2 setose punctures each side of midline, evenly spaced along rounded apical edge; ventrites 3 and 4 foveate laterally (very shallow). Anterior metaventrite process a short triangle with carina narrow the entire length.

Male genitalia: (some variation in specimens from distinct populations). Apical portion of penis lobe asymmetrically hooked with a dstinct deflection to right of vertical axis (VV) ( Fig. 15A ); apex broad (especially Moirs Hill), ventral process a rounded point slightly forward of vertical axis, apex asymmetrical curved to form dorsal process ( Fig. 62 PL), process broad, flattened without recurve, short, gentle curve to shaft; shaft of penis lobe (apical portion) with weak curve to right (VV); overall length of penis lobe slightly curved ventrally (LV) ( Fig. 16A ), shaft narrow at apex to ⅓ of length, then gradually broadens to base. 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 without projection; setal (scales) coverage of the apical plate extensive (76–100%); size of left setose flange small; size of right setose flange very large. Left paramere basal lobe narrow and rectangular with moderate anterior hump forming gradual (45°) slope to arm ( Fig. 62 LP); arm very short and narrow, broadened to form short and broad terminal lobe with apical tuft of medium-lengthed setae, very short and sparsely distibuted setae continued along arm junction curve ( Fig. 62 LP); ventral edge straight. Right paramere narrowly triangular, gradually narrowed to terminus with a double row of very long setae along apical ¾ of ventral edge ( Fig. 62 RP), apical ⅓ inwardly curved toward penis lobe.

Female genitalia: Basal gonocoxite 1 ( Fig. 5 ) short and broad, flattened apically; internal dorso-lateral carina with 3 setae; ventral surface with a few rugose grooves. Gonocoxite 2 short and rounded, slightly recurved around apical edge. Ramus short and broad.

Comments: Mecodema undecimus is widespread from the Puhoi River north to Warkworth, and can be found in pine ( Pinus radiata ) plantation forests in addition to native forests.

Distribution: New Zealand, North Island, Auckland, Rodney District, Mc Elroy Scenic Reserve, Pohuehue Scenic Reserve, Moirs Hill Scenic Reserve, Puhoi (north of the Puhoi River).

Holotype: NZAC male labelled. NEW ZEALAND AK, Moirs Hill Walkway 3651 S 17462 E 150m 12.XI–10 XII 2001 Larivière.Larochelle / wet broadleaf forest along stream Pittraps / HOLOTYPE Mecodema undecimus n. sp. design. DS Seldon, TR Buckley 2018 [red label].

Paratypes: 1♂, NEW ZEALAND AK , Moirs Hill Walkway 3651 S 17462 E 150m 15.X–12 XI 2001 Larivière.Larochelle / wet broadleaf forest along stream Pittraps ( NZAC) ; 1♂, NEW ZEALAND AK , Moirs Hill Walkway 3651 S 17462 E 150m 12.IX–15 X 2001 Larivière.Larochelle / wet broadleaf forest along stream Pittraps ( NZAC) ; 2♂, 1♀, NEW ZEALAND AK , M c Elroy S.R. 29 XII–05 I 1999 #289 #290 # 295 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 2♂, 1♀, NEW ZEALAND AK , M c Elroy S.R. 22–29 XII 1998 #195 #196 # 197 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♀, NEW ZEALAND AK , M c Elroy S.R. 15–22 XII 1998 # 103 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♀, NEW ZEALAND AK , M c Elroy S.R. 16–23 III 1999 #1347 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♂, NEW ZEALAND AK , Pohuehue S.R. 05–12 I 1999 # 395 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♂, NEW ZEALAND AK , Pohuehue S.R. 15–22 XII 1998 # 108 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♂, NEW ZEALAND AK , Pohuehue S.R. 16–23 III 1999 #1358 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♀, NEW ZEALAND AK , Pohuehue S.R. 23–30 III 1999 #1451 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♀, NEW ZEALAND AK , Pohuehue S.R. 09–16 III 1999 #1261 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♂, NEW ZEALAND AK , Pohuehue S.R. 06–13 IV 1999 #1643 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) ; 1♂, NEW ZEALAND AK , Pohuehue S.R. 05–12 I 1999 # 395 P. Paquin & N. Dupérré / Pitfall traps Moist podocarp x broadleaf forest Landscape Patch Dynamic Project ( NZAC) .

Etymology: Undecimus is Latin for ‘eleventh’, and Mecodema undecimus is the eleventh species that DSS recognised as new.

Figures

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 5. The entire female reproductive tract (ventral view) including taxonomic structures (for all other abbreviated structure names see Seldon et al. 2012). However, for this revision only the following structures are important: HS = helminthoid sclerite; G1 = gonocoxite 1; G2 = gonocoxite 2; TDC = transverse dorsal carina; R = ramus.

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 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 15. The penis lobe in ventral view showing the relative deflection to right of vertical: (A) distinctly deflected (M. regulus); (B) moderately deflected (M. haunoho); (C) slightly deflected (M. oregoides). Scale bars = 1 mm. Structures of penis lobe indicated are: base (B); lateral edge (LE); apical portion (AP); ventral edge (ƑE).

FIGURE 16. Relative strength of the ventral curve over the length of the penis lobe (lateral view): (A) slightly curved (M. oblongum); (B) moderately curved (M. ponaiti); (C) distinctly curved (M. manaia). Scale bar = 1 mm.

FIGURE 62. Mecodema undecimus 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.