Mecodema papake, 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 : 85-88

Mecodema papake sp. n.

Figure 44 .

Diagnosis: Differs from other Mecodema species in the North Island by having: 1, vertexal groove defined by several scattered punctures along entire length, increased in number laterally; 2, 7 th strial setal pattern with 3 evenly spaced setose punctures in anterior ½, 5 regular spaced setose punctures in posterior ½, setose punctures large; 3, unique form of the apical portion of the penis lobe ( Fig. 44 PL).

Description: Length 29–32.5 mm, pronotal width 8–9.2 mm, elytral width 9.6–10.5 mm. Colour of entire body matte black, coxae and legs matte dark reddish-brown to matte black.

Head: Broad and flat ( Fig. 14A ). Vertex smooth (very fine lines forming an isodiametric pattern laterally maybe present); vertexal groove defined by several scattered punctures along entire length, increased in number laterally; small supraorbital puncture bearing 3–4 setae; 2–3 shallow (may be indistinct) supraorbital grooves; frons smooth; frontoclypeal suture narrowly defined, formed by raised cuticle of clypeus, tentorial pits small; anterior area of clypeus narrowly grooved (may be indistinct), 1 setose puncture each side bearing 1–2 setae ( Fig. 44 ). Labrum rectangular, anterior edge distinctly emarginated with 2 proximate central setae, 2 setae each side evenly spaced. Mentum lobes rounded ( Fig. 12F ), median process very short and broad, moderately angled upward (45°), strongly indentate ( Fig. 12A ); mentum setae absent. Submentum sclerite constriction ( Fig. 8 ) broad with 6–8 evenly spaced setae (wide gap medially). Stipes with 2 basal setae. Gula pits small to indistinct, suture poorly defined, gula weakly convex with very fine transverse lines. Gena with a fine isodiametric pattern across the entire area.

Prothorax: Prothoracic carina broad at shoulder but narrowed posterad, crenulations absent with 7–10 setae each side, extended to anterior angle; posterior lateral sinuation indistinctly carinate, slightly angled inward; pronotum broad and flattened, overall shape triangularly cordate ( Fig. 44 ), distinctive ‘rolled-edge’ present between foveae and posterior edge of disc; midline ( Fig. 11 ) indistinctly impressed, anterior medial triangular impression and posterior medial diamond-shaped impression present, disc with fine transverse wrinkles laterally; pronotal foveae shallow and narrow; anterior edge weakly inwardly curved, posterior edge relatively straight (may be slightly inwardly curved medially. Prosternum flat and smooth (may have depressions); proepisternum ( Fig. 2 ) without microsculpture. Procoxal setae absent; protibia distally expanded and shovel-like ( Fig. 10B ).

Elytra: Broad and flattened; humeral angle anteriorly convergent ( Fig. 6A ); basal margin gently curved and very gently sloped to base, all striae and intervals extended; lateral carina narrow the entire length, extended to humeral angle; humerus with 3 setose punctures: 2 proximate to humerus, 1 double-spaced posterad ( Fig. 44 ); suture defined but no more so than striae; all striae with very small, regularly distributed asetose punctures, may be slightly increased in size laterally; all intervals flat with only a very slight increase in convexity laterally; interval microsculpture absent; 7 th strial setal pattern with 3 evenly spaced setose punctures in anterior ½, 5 regular spaced setose punctures in posterior ½ ( Fig. 44 ), setose punctures large.

Ventral surface: Mesepisternum and metepisternum ( Fig. 2 ) without microsculpture; setose punctures present on mesocoxae (1–2) and metacoxae (2). All abdominal ventrites lineate; ventrites 3–5 with 1 setose puncture each side of midline; ventrite 6 setae present: ♂ 1 setose puncture each side at junction of straight apical edge and curve anterad, ♀ with 1 setose puncture each side at junction of the bluntly rounded apical edge and curve anterad; lateral foveae absent. Anterior metaventrite process ( Fig. 2 ) an elongated triangle with a broad carina the entire length.

Male genitalia: Apical portion of penis lobe asymmetrically hooked with moderate deflection to right of vertical axis (VV) ( Fig. 15B ); apical portion broad ( Fig. 44 PL) with ventral process a bluntly rounded point medially, apex symmetrically curved upward to form dorsal process, dorsal process a short, broad and flattened hook (not recurved) with a very short and tight curve to shaft; shaft of penis lobe narrow the entire length ( Fig. 44 PL), ventral edge moderately curved to right (VV); overall length of penis lobe slightly curved ventrally (LV) ( Fig. 16A ). 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 greatly expanded with projection; setal (scales) coverage of the apical plate moderate (26–75%); size of left setose flange small; size of right setose flange absent. Left paramere articulated at right angle to aedeagus, basal lobe rectangular ( Fig. 44 LP), moderately humped with anterior edge steeply angled (60°) to a very short and broad arm; arm continued to define broad and short terminal lobe, very sparse tuft of setae at ventral apex, setae extended along apical ⅓ of ventral edge ( Fig. 44 LP); ventral edge of basal lobe straight. Right paramere an elongated triangle with a double row of setae extended along apical ¾ of ventral edge ( Fig. 44 RP); arm and terminal lobe curved inwardly toward penis lobe.

Female genitalia: Basal gonocoxite 1 ( Fig. 5 ) short and broad, ventral surface with a few grooves, dorsal surface with scattering of sensilla pits, internal dorso-lateral carina with setae absent. Gonocoxite 2 paddle-like and flattened. Ramus short and broad.

Comments: Mecodema papake is one of a number of closely related species found in forest fragments in Northland. This species is also found in the Maungataniwha Range, but is restricted to these areas as M. kokoroiho is to the west (Warawara Forest) and M. ngaiatonga is found to the east in Russell Forest.

Distribution: New Zealand, North Island, Northland, Maungataniwha Range and Puketi-Omahuta Forest.

Holotype: NZAC male labelled. NEW ZEALAND ND Puketi Forest Manginangina Tk PTs 1–14 Oct 2016 D.S. Seldon DSS135 / mixed podocarp-broadleaf canopy, pitfalls placed around tree fall 50 m from road / HOLOTYPE Mecodema papake n. sp. design. DS Seldon, TR Buckley 2018 [red label].

Paratypes: 1♀, NEW ZEALAND ND Puketi For., Waipapa Riv tk, E branch 200m 30.I.–4.II.1995 Larivière.Larochelle / Pittraps Taraire-tree fern for., nr stream ( NZAC); 1, NEW ZEALAND ND Puketi Forest Manginangina Tk PTs 1–14 Oct 2016 DS Seldon DSS135 / mixed podocarp-broadleaf canopy, pitfalls placed around tree fall 50 m from road / CAR 317 ( NZAC); 1, Kaeo , A. Short, 20/8/1951 / AMNZ 40754 ; 1♂, Mangamuka, C.E. Clarke / C.E. Clarke Collection ( AMNZ); 1 , 2♂, NEW ZEALAND ND Puketi For., Waipapa Riv tk, E branch 200m 30.I.–4.II.1995 Larivière.Larochelle / Pittraps Taraire-tree fern for., nr stream ( NZAC) .

Etymology: Mecodema papake was named by the Piki Te Aroha Marae Committee (2017): after the place where specimens were originally collected, Waipapa River valley (papa, the locality; -ke, originating from), Puketi Forest.

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 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 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 44. Mecodema papake 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.