Pelodiaetodes Moore 1980,

Sokolov, Igor M., 2015, Review of the species of Pelodiaetodes Moore (Coleoptera: Carabidae: Bembidiini: Anillina) of New Zealand, Zootaxa 3963 (4), pp. 561-582: 562-570

publication ID

publication LSID

persistent identifier

taxon LSID

treatment provided by


scientific name

Pelodiaetodes Moore 1980


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 (7 th, 8 th and 9 th) equidistant, but not aligned, virtually forming an obtuse isosceles triangle with 8 th 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. 5View FIGURE 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. 1View FIGURE 1 A –B). Mentum with two pairs of long primary (paramedial and lateral) setae ( Fig. 4View FIGURE 4 C, pms, lms). Submentum with two pairs of long primary setae in two rows (lss, prss) and few additional shorter setulae ( Fig. 4View FIGURE 4 C). Maxilla with long stipetal and palpiferal setae ( Fig. 4View FIGURE 4 D). Pronotum with two long primary lateral setae (midlateral, ls, and basilateral, bs) on each side ( Fig. 1View FIGURE 1 C –D). Elytra either with 1 or 3 discal setae ( Fig. 2View FIGURE 2 C –D), with scutellar (ed 2) and apical (ed 8) setae. Last three (7 th, 8 th and 9 th) pores (eo 7, eo 8 and eo 9) of umbilicate series equidistant, but not aligned, with 8 th pore shifted towards the disc and virtually forming an obtuse isosceles triangle. 7 th pore aligned with 6 th and 9 th. Fifth visible sternite of male with two and of female with four setae along the posterior margin.

Head ( Fig. 1View FIGURE 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. 1View FIGURE 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. 4View FIGURE 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. 4View FIGURE 4 D). Maxillary palps similar to Bembidion ( Maddison 1993)  with basal trianguloid cardo, and stipes with dorsal and ventral lobes (dls, vls), dimerous galea (g 1, g 2), and standard lacinia (lc). Palpus with moderately long 4 th palpomere (mp 4), 0.25–0.30 length of palpomere 3 (mp 3).

Labium ( Fig. 4View FIGURE 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. 1View FIGURE 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. 2View FIGURE 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. 2View FIGURE 2 A –B). Externally visible, triangular, with broadly rounded apex.

Elytra ( Fig. 2View FIGURE 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 (ed 2) downward to the 9 th umbilical pore (eo 9). Humeri rounded, to form oblique angle with longitudinal axis of body. Basal margination (bm) indistinct ( Fig. 2View FIGURE 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. 3View FIGURE 3). Legs of moderate length, not elongate. Prothoracic legs of males with first 2 tarsomeres (ta 1–2) markedly dilated apico-laterally with two rows of oval articulo-setae (as) ( Stork 1980) on the ventral surface ( Fig. 3View FIGURE 3 B). Protibiae ( Fig. 3View FIGURE 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 1 st tarsomere (ta 1). Profemora moderately swollen. Mesotibiae ( Fig. 3View FIGURE 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. 3View FIGURE 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. 3View FIGURE 3 A –B), last and 1 st tarsomeres are the longest, 2–4 tarsomeres of equal length on the tarsi of all legs, 1 st tarsomere shorter than combined length of 2–4 tarsomeres. Tarsal claws simple, untoothed ( Fig. 3View FIGURE 3 A –B).

Abdominal ventrites. Five visible abdominal ventrites: 2 nd ventrite longest, 2.5–3 times longer than 3 rd or 4 th, 3 rd and 4 th equal in length; the last, 5 th, 1.3–1.6 times longer than 4 th. Intercoxal process of 2 nd ventrite broad, subparallel, conically rounded anteriorly.

Male genitalia ( Fig. 7–8View FIGURE 7View FIGURE 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. 7View FIGURE 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. 9–10View FIGURE 9View FIGURE 10). Gonocoxite 1 asetose (gc 1). Gonocoxite 2 falciform (gc 2), 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. 11View FIGURE 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.