Endogeophilus ichnusae, Bonato & Zapparoli & Drago & Minelli, 2016

Bonato, Lucio, Zapparoli, Marzio, Drago, Leandro & Minelli, Alessandro, 2016, An unusually elongate endogeic centipede from Sardinia (Chilopoda: Geophilidae), European Journal of Taxonomy 231, pp. 1-19 : 7-12

Endogeophilus ichnusae gen. et sp. nov.

urn:lsid:zoobank.org:act:BF3DE3C0-542A-4767-A62E-6C9D6A2923AD

Figs 1–4

Geophilidae sp. nov.– Zapparoli 2009: 145, 155.

Geophilidae n. sp.– Zapparoli 2011: 240.

Diagnosis

As for the genus (see above).

Etymology

From the Latin Ichnusa , which is from the Greek ΙχΝΟΥσσα, ancient name of Sardinia. The species epithet is a noun in the genitive case.

Type material

Holotype

SARDINIA: adult ♀, 34 mm long, with 107 leg-bearing segments, Colle di Campanasissa, between Siliqua ( Province of Cagliari ) and Nuxis ( Province of Carbonia-Iglesias ), 280 m; 27 Dec. 2006, L. Fancello leg., in ethanol, head detached from trunk ( MSNG, code 58344).

Paratype A

SARDINIA: adult ³, 32 mm long, with 95 leg-bearing segments, same site and date of the holotype, in ethanol, head detached from trunk, some pieces of trunk gold-coated for SEM examination ( MZ).

Paratype B

SARDINIA: adult ³, 31 mm long, with 91 leg-bearing segments, Mamenga, Marganai forest, near Domusnovas (Province of Carbonia-Iglesias), 610 m, 1 Mar. 2006, L. Fancello leg., in ethanol, not dissected ( PD, code 1373).

Description

Female

Description of holotype (see also Figs 1 A–F, 2, 4)

GENERAL FEATURES. Body remarkably narrow, 34 mm long, uniformly 0.5 mm wide for most part of the trunk, only slightly narrowing anteriorly along ca 30 most anterior leg-bearing segments and backwards along ca five most posterior leg-bearing segments, both the first and the ultimate leg-bearing segments being 0.4 mm wide. Legs relatively short, most of them uniformly 0.4 mm long, a few tens of most anterior pairs decreasing gradually, the legs of the first pair being 0.3 mm long. Colour (in ethanol) almost uniformly pale yellow, only the forcipular condyles and the distal part of the tarsungula distinctly darker.

CEPHALIC CAPSULE. Cephalic plate sub-rectangular, 1.2 times as long as wide, 0.9 times as wide as the forcipular tergite, the anterior margin slightly angulated with a medial notch, the lateral margins slightly convex, the posterior margin straight; transverse suture absent; setae rare and short, up to ca 15 μm long. Clypeus uniformly areolate, without clypeal areas and without plagulae; lateral margins complete; a total of 6 setae, arranged in a longitudinal series of three pairs on the anterior part of the clypeus. Pleurites uniformly areolate, each with 2–3 setae on the anterior part. Labrum composed of an intermediate part, which is continuous with the clypeus and bears two medial short tubercles and two lateral bristles, and lateral parts bordered anteriorly by a complete sulcus and posteriorly by a row of bristles.

ANTENNAE. Slender, 3.6 times as long as the head. Intermediate articles up to 2.5 times as long as wide. Article XIV 1.9 times as long as wide, 1.7 times as long as article XIII and only slightly wider than the latter. Setae gradually denser and shorter from basal to distal articles, both ventrally and dorsally. Apical sensilla ca 6 μm long, spear-like, without projections, only gently narrowing at about mid-length. Clublike sensilla ca 11 μm long, only on article XIV, grouped on the distal parts of both internal and external sides. Three longitudinal rows of proprioceptive spine-like sensilla at the bases of articles: ca 3 sensilla in each row on articles II–V, apparently a single sensillum on each side of articles VII–IX and XI–XIII; only a single, dorsal sensillum on articles VI, X and XIV. Groups of 1–3 sensilla, similar to the apical ones, ca 6 μm long, on both dorso-external and ventro-internal position, close to the distal margin of articles V, IX and XIII.

MANDIBLES. A single pectinate lamella on each mandible.

FIRST MAXILLAE. Coxosternite entire, without mid-longitudinal sulcus, without setae. Coxal projection sub-triangular, longer than wide, bearing 1–2 basal setae and ca 5–6 more distal spine-like sensilla, the tip covered with fine scales. Telopodite of two articles, the basal one without setae, the distal one with 2 setae and ca 4 spine-like sensilla, the tip covered with fine scales. Coxosternal and telopodital lappets present, very short.

SECOND MAXILLAE. Coxosternite entire, the intermediate part uniformly sclerotized as the remaining parts; anterior margin widely concave; no sclerotized ridges; setae only close to the anterior margin; metameric pores featuring as transversal slits, close to the postero-medial margin. Telopodite composed

of three articles, only slightly narrowing towards the tip; pretarsus in the shape of a simple claw, subconic, only slightly bent, with a small dorsal bulge.

FORCIPULAR SEGMENT. Tergite sub-trapezoid, the lateral margins distinctly converging anteriorly, 1.8 times as wide as long, posteriorly almost as wide as the subsequent metatergite. Pleurites without scapular ridge. Exposed part of the coxosternite 1.2 times as wide as long; anterior margin slightly projecting anteriorly with an intermediate shallow concavity, without denticles; coxopleural sutures complete, entirely ventral, only slightly sinuous, and strongly converging posteriorly; chitin-lines distinct, reaching the condyles, only slightly curved and converging posteriorly. Basal distance between the forcipules 0.1 of the maximum width of the coxosternite. Trochanteroprefemur 1.3 times as wide as long, the internal side much shorter than the external side, without denticles. Forcipular intermediate articles distinct, without denticles, each with a shallow bulge only. Tarsungulum 1.9 times as long as wide, with a basal sub-conic tubercle; distal part almost straight, the internal side with a shallow longitudinal groove between two distinct ridges. Poison calyx sub-spherical, located in the distal part of the trochanteroprefemur.

LEG- BEARING SEGMENTS. A total of 107 leg-bearing segments. Metatergite 1 wider than the subsequent one, lateral margins converging posteriorly, without pretergite. No paratergites. Metasternites slightly longer than wide or approximately as long as wide, uniformly areolate, with dense micropores; setae sparse, at most ca 10 M m long, approximately arranged into transversal rows; metasternites of some anterior segments with a very shallow, bilobate socket on the anterior margin, 0.6 times as wide as the margin of metasternite, resembling a “carpophagus” pit¸ but no corresponding medial peg on the posterior margin. Glandular pores on the metasternites from 2 to penultimate, up to 20–25 pores on each metasternite, loosely arranged in a sub-ovoid/sub-triangular pore-field on the posterior half of each metasternite; each pore with a sub-circular lumen with a diameter of 1.1–1.3 M m, surrounded by a distinct ring-like uninterrupted ridge. Procoxa distinctly longer than metacoxa, both sclerites without glandular pores. Leg claws simple, uniformly bent; a pair of accessory spines, reaching approximately the mid-length of the pretarsus, the anterior spine slightly longer than the posterior one.

ULTIMATE LEG- BEARING SEGMENT. Pleuropretergite entire, lacking sutures or sulci or notches, 3.4 times as wide as long. Metatergite sub-trapezoid, 1.3 times as wide as long, lateral margins convex and distinctly converging posteriorly, posterior margin slightly convex. Presternite 5.0 times as wide as long, not medially constricted. Metasternite sub-trapezoid, 1.2 times as wide as long, anteriorly 1.4 times as wide as posteriorly, lateral margins anteriorly slightly convex, posteriorly almost straight and converging backwards, posterior margin slightly concave; setae uniformly sparse. Coxopleuron 2.0 times as long as wide, 1.5 times as long as the metasternite; setae uniformly sparse. Coxal organs of each coxopleuron opening through 13–14 independent pores, which are approximately aligned from the dorsal to the ventral surface through the anterior side of the coxopleuron: most pores covered by pleuropretergite, metatergite and presternite; 2 pores exposed on the dorso-lateral side; 6–7 partially exposed on the ventral side, close to the metasternite; a single pore isolated on the postero-central part of the ventral side. Telopodite 7.6 times as long as wide, 2.0 times as long and 1.4 times as wide as the penultimate telopodite; 6 articles, all covered dorsally with sparse longer setae, ventrally with dense shorter setae. Pretarsus in the shape of a pointed claw, similar but only half the length of the penultimate.

POSTPEDAL SEGMENTS. Genital pleurosternite entire. Gonopods in the shape of a short slightly bilobate lamina. Anal organs relatively large, anal pores exposed.

Male

Description of the terminal part of the body of the paratype B (see also Fig. 1G ). Same as the holotype, except for the following characters.

ULTIMATE LEG- BEARING SEGMENT. Coxopleuron 1.8 times as long as wide; setae distinctly denser close to the postero-mesal margin. Coxal organs of each coxopleuron opening through 14–15 independent pores. Telopodite 7.0 times as long as wide, 2.0 times as long and 1.7 as wide as the penultimate.

POSTPEDAL SEGMENTS. Complete sutures between the genital sternite and the pleurites. Gonopods biarticulated, well separated, with a sub-conic penis in between.

Distribution and habitat

Endogeophilus ichnusae gen. et sp. nov. has been found only in two localities, about 25 km from each other, in the Sulcis-Iglesiente area, SW Sardinia, at 280–610 m above sea level ( Fig. 5 ). The type locality (Colle di Campanasissa) has a granitic substrate covered with maquis consisting of Pistacia spp. (L. Fancello, pers. com.), whereas the other locality (Mamenga) has a calcareous substrate covered with Quercus ilex L. wood ( Bardiani 2011).

Figures

Fig. 1. Endogeophilus ichnusae gen. et sp. nov. A–F. Holotype, ♀. A. Anterior part of the body, dorsal view, setae omitted. B. Head, without antennae, and forcipular segment, dorsal view. C. Leg-bearing segment 21, dorsal view. D. Leg-bearing segment 21, ventral view. E. Head, without antennae, ventral view. F. Ultimate leg-bearing segment and postpedal segments, ventral view, setae omitted. G. Paratype B, ³, ultimate leg-bearing segment and postpedal segments, ventral view, setae omitted. Line drawings based on photos taken at the microscope. Scale bars = 200 µm.

Fig. 2. Endogeophilus ichnusae gen. et sp. nov., holotype, ♀, forcipular segment, left half. A. Dorsal view. B. Ventral view. Scale bar = 100 µm.

Fig. 3. Endogeophilus ichnusae gen. et sp. nov., paratype A, ³. A. Leg-bearing segment 20, ventral view. B. Posterior part of leg-bearing segment 21 and anterior part of segment 22, ventral view. C. Right forcipular tarsungulum, ventral view. D. Right tarsungulum, ventro-mesal view. E. Right tarsungulum, frontal view. SEM micrographs. Scale bars = 50 µm.

Fig. 4. Forcipules of Endogeophilus ichnusae gen. et sp. nov. and the two most similar geophilid species. Left part of the forcipular segment, ventral view, in adult females. A. E. ichnusae gen. et sp. nov., holotype, ♀, original drawing. B. Geophilus electricus (Linnaeus, 1758), original drawing from a representative specimen, ♀ (see ‘Material and methods’). C. Galliophilus beatensis Ribaut & Brolemann, 1927, holotype, ♀, redrawn from Brolemann (1927). Scale bars = 200 µm.

Fig. 5. Localities where Endogeophilus ichnusae gen. et sp. nov. has been collected, in the Sulcis- Iglesiente, Sardinia. The type locality is indicated by a star.