Pelodiaetodes Moore 1980
Creators: name: Sokolov, Igor M.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Pelodiaetodes

description: Pelodiaetodes Moore 1980
Recognition. The members of this genus are distinguished from the other New Zealand representatives of Anillina by the following combination of characters: eyes absent; head with long fronto-lateral carinae; labium free, with distinct mental-submental suture; pronotum cordiform, with short subparallel basal constriction, with prominent anterior angles and distinct tubercle anterior to the posterior angles; each elytron with oblique longitudinal groove; last three pores of umbilicate series (7th, 8th and 9th) equidistant, but not aligned, virtually forming an obtuse isosceles triangle with 8th pore shifted towards disc. The cordiform pronotum with basal constriction, and grooved elytra distinguish the representatives of Pelodiaetodes from numerous New Zealand species of Zeanillus Jeannel and Nesamblyops Jeannel. Developed fronto-lateral carinae and grooved elytra separate Pelodiaetodes from the endogean Hygranillus Moore. A presence of the distinct tubercle anterior to the posterior angles of pronotum allows the separation of the species of Pelodiaetodes from the species of Pelodiaetus.
Description. Size. SBL range 1.38–1.72 mm.
Habitus. Body form weakly convex, subparallel (Fig. 5).
Color. Body brunneorufous or rufotestaceous, appendages testaceous.
Microsculpture. Dorsal microsculpture of polygonal sculpticells, on head, pronotum and elytra with isodiametric mesh pattern through over the dorsal surface. Development of microsculpture varies on different body parts. On head and disc of pronotum microlines less pronounced, fine, while on elytra microlines very distinct, forming well pronounced sculpticells with “scaly” mesh pattern.
Luster. Body surface shiny.
Macrosculpture. Body surface sparsely and finely punctate.
Vestiture. Body surface covered with sparse yellowish short setae. Vestiture of elytra short (less than one-third length of discal setae).
Fixed setae. Primary head setae include a pair of clypeal (cs), a pair of frontal (fs), a pair of anterior supraorbital (ass) and a pair of posterior supraorbital (pss) setae (Fig. 1 A–B). Mentum with two pairs of long primary (paramedial and lateral) setae (Fig. 4 C, pms, lms). Submentum with two pairs of long primary setae in two rows (lss, prss) and few additional shorter setulae (Fig. 4 C). Maxilla with long stipetal and palpiferal setae (Fig. 4 D). Pronotum with two long primary lateral setae (midlateral, ls, and basilateral, bs) on each side (Fig. 1 C–D). Elytra either with 1 or 3 discal setae (Fig.2 C–D), with scutellar (ed2) and apical (ed8) setae. Last three (7th, 8th and 9th) pores (eo7, eo8 and eo9) of umbilicate series equidistant, but not aligned, with 8th pore shifted towards the disc and virtually forming an obtuse isosceles triangle. 7th pore aligned with 6th and 9th. Fifth visible sternite of male with two and of female with four setae along the posterior margin.
Head (Fig. 1 A–B). Anterior margin of clypeus (cl) straight. Frontal area flat without tubercle medially near frontoclypeal suture. Fronto-lateral carinae distinct and long.
Eyes. Eyes absent.
Antennae. Submoniliform, 11-segmented, extended to about posterior margin of pronotum. Antennomeres 1 and 2 elongate, of equal length and 1.4–1.5 times longer than antennomere 3, which is only slightly elongate and 1.2–1.3 times longer than antennomere 4. Antennomeres 4 to 10 globose, last antennomere conical and 1.6–1.8 times longer than penultimate antennomere.
Labrum (Fig. 1 A–B). Labrum (l) transverse with almost straight, entire anterior margin and with six setae apically, increasing in size from the central pair outwards.
Mandibles (Fig. 4 A–B). General plan of Bembidion type (Maddison 1993). Right mandible with distinct anterior (art) and posterior retinacular (prt), weakly developed terebral (tt), distinct premolar (pm) and molar (mt) teeth. Left mandible with distinct terebral (tt), premolar (pm) and molar (mt) teeth only.
Maxillae (Fig. 4 D). Maxillary palps similar to Bembidion (Maddison 1993) with basal trianguloid cardo, and stipes with dorsal and ventral lobes (dls, vls), dimerous galea (g1, g2), and standard lacinia (lc). Palpus with moderately long 4th palpomere (mp4), 0.25–0.30 length of palpomere 3 (mp3).
Labium (Fig. 4 C). Labium with mental tooth; mentum (m) and submentum (sm) split, with mental-submental suture (ms) and with slightly enlarged lateral mental lobes (llm). Glossal sclerite (gsc) membraneous apically, with two setae, paraglossae lacking.
Prothorax (Fig. 1 C–D, 6). Pronotum cordiform, moderately convex, slightly sinuate posteriorly, with wide marginal gutter (mg) and with short subparallel basal constriction. Posterior margin of pronotum almost straight, slightly oblique laterally. Anterior angles prominent, moderately protruding forward. Posterior angles denticulate, with 1 distinct tubercle (axt), bearing the basolateral seta, anterior to the angles (Fig. 2 A–B). Widths across anterior margin much greater than between posterior angles (WPa/WPp varies from 1.15 to1.24 among species).
Scutellum (Fig. 2 A–B). Externally visible, triangular, with broadly rounded apex.
Elytra (Fig. 2 C–D). Elytra relatively short (LE/SBL from 0.52 to 0.54 among species) without visible interneurs, but with oblique longitudinal groove (eg), stretching from the scutellar pore (ed2) downward to the 9th umbilical pore (eo9). Humeri rounded, to form oblique angle with longitudinal axis of body. Basal margination (bm) indistinct (Fig. 2 A–B). Apical half of elytra with shallow subapical sinuation.
Hind wings. Absent.
Pterothorax. Metaventrite short, distance between meso- and metacoxae about 0.5–0.8 diameter of mesocoxa. Metanepisternum short, subquadrate, with anterior and outer margins of equal length. Metendoventrite crossshaped with lateral arms.
Legs (Fig. 3). Legs of moderate length, not elongate. Prothoracic legs of males with first 2 tarsomeres (ta1–2) markedly dilated apico-laterally with two rows of oval articulo-setae (as) (Stork 1980) on the ventral surface (Fig. 3 B). Protibiae (Fig. 3 C–D) with antenna cleaner of type B (Hlavac 1971), with both anterior (asr) and posterior (psr) apical setal rows and concave apico-lateral notch. Length of anterior spur (asp) equal to length of the 1st tarsomere (ta1). Profemora moderately swollen. Mesotibiae (Fig. 3 E–H) with 1–2 rows of modified posterodorsal setae (msms) at apical half, with two terminal spurs (mss) and tibial brush (msb). Metafemora unmodified, metatibiae (Fig. 3 I–L) with row of modified posterodorsal setae (mtms) in apical half, with two terminal spurs (mts) and tibial brush (mtb). Tarsi pentamerous (Fig. 3 A–B), last and 1st tarsomeres are the longest, 2–4 tarsomeres of equal length on the tarsi of all legs, 1st tarsomere shorter than combined length of 2–4 tarsomeres. Tarsal claws simple, untoothed (Fig. 3 A–B).
Abdominal ventrites. Five visible abdominal ventrites: 2nd ventrite longest, 2.5–3 times longer than 3rd or 4th, 3rd and 4th equal in length; the last, 5th, 1.3–1.6 times longer than 4th. Intercoxal process of 2nd ventrite broad, subparallel, conically rounded anteriorly.
Male genitalia (Fig. 7–8). Median lobe of aedeagus anopic, elongate, slightly twisted and moderately arcuate. Internal sac with two copulatory sclerites, representing by dorsal and ventral plates. Dorsal plate (dp) in form of a stick-like plate, bifurcating or not apically. Ventral plate (vp) much smaller than dorsal plate, claw-like, bifid basally. Additional spines or scaled membranous fields of internal sac are absent. Parameres typically bisetose, except left paramere of P.nunni 3-setose (Fig. 7 R). Left paramere large and broad evenly tapered to apex, right paramere short. Ring sclerite triangular with trianguloid handle-like extension (hd) of similar shape among species.
Female internal genitalia (Fig. 9–10). Gonocoxite 1 asetose (gc1). Gonocoxite 2 falciform (gc2), 1.6–1.8 times longer than its basal width, moderately curved, with medial basal ridge (mbr), and with medial (mes) and lateral (les) ensiform and apical nematiform (ns) setae. Shape of medial basal ridge and length of ensiform setae vary among species. Laterotergite (lt) with 8–11 setae. Spermatheca (sp) sclerotized, small, rufous, subparallel, either with enlarged basal half or almost spherical.
Included taxa. The genus comprises two subgenera and five species: nominotypical subgenus includes P. prominens Moore, P. moorei, sp. n., P. constricticollis, sp. n., P. aldermensis, sp. n., and subgenus Monosetodes, subgen.n., includes P. nunni, sp. n.
Geographical distribution. The species of this genus are known from two widely separated regions of New Zealand (Fig. 11). Species of the Pelodiaetodes s.str. inhabit the northern half of the North Island, while the only representative of the subgenus Monosetodes is known from a single locality in the southern part of the South Island.
Way of life. According to the label information, specimens of Pelodiaetodes were taken either from the leaf litter or from the washed soil samples in broadleaf and kauri forests, from the litter of a shearwater colony (Aves, Procellaridae, Puffinus bulieri), from decayed or rotten wood, and from mosses at tree bases and on the ground. Collecting dates are August, September, October, November, December, January and April.
Relationships. Morphologically, the putative closest relative of Pelodiaetodes among the New Zealand anillines is Pelodiaetus. Both genera share developed fronto-lateral carinae, cordiform shape of pronotum and distinct longitudinal elytral groove, distinguishing them by the combination of these characters from any other New Zealand Anillina. Compared with other Anillina the members of Pelodiaetodes (and Pelodiaetus) differ from Australian Illaphanus and Madagascan Bulirschia and Malagasytyphlus by the presence of a mental tooth, thus formally belonging to another anilline assemblage sensu Jeannel (1963). But subsequent authors showed the low taxonomic value of the mental tooth at a suprageneric level and the usefulness of this character only for generic discrimination (Sciaky & Zaballos 1993; Zaballos & Casale 1997; Giachino 2005; Giachino & Vailati 2011). According Giachino (2008) the closest morphological relative to the New Zealand Anillina with grooved elytra might be the Madagascan Malagasydipnus. Species of the latter genus share with the members of Pelodiaetodes and Pelodiaetus such characters as (i) presence of the mental tooth; (ii) cordiform pronotum with distinct posterior angles, but without denticles in front of them; (iii) three discal elytral setae; (iv) two dilated protarsomeres in males; (v) and two, flagelliform and falciform, structures in the inner sac of median lobe. Nevertheless, the position of Pelodiaetodes within the group of Anillina with grooved elytra remain unclear at present, and awaits molecular data phylogenetic analysis along with thorough morphological phylogenetic analysis of the entire group.
The key provided below allows identification of males of Pelodiaetodes., including separation from all other New Zealand aniline genera. Females of Pelodiaetodes can be identified only by distributional information, preferably by association with microsympatric males.
description: Published as part of Sokolov, Igor M., 2015, Review of the species of Pelodiaetodes Moore (Coleoptera: Carabidae: Bembidiini: Anillina) of New Zealand, pp. 561-582 in Zootaxa 3963 (4) on pages 562-570, DOI: 10.11646/zootaxa.3963.4.4, http://zenodo.org/record/235706