Geophilus gigas Attems, 1951

Zarei, Roghaieh, Rahimian, Hassan & Bonato, Lucio, 2013, Morphology of a neglected large-sized species of Geophilus from Iran (Chilopoda: Geophilidae), Zootaxa 3736 (5), pp. 486-500 : 487-491

Geophilus gigas Attems, 1951

Full list of citations. Attems 1951: 392 (original description)

Type localities. Koohrang mountains (Zagros mountains, Iran). Ghori Gol ( Azerbaijan, Iran).

Synonyms. None.

Differential diagnosis. A Geophilus species with maximum body length at least 6 cm, antennae 3–4 times as long as the head, no clypeal areas, labrum with 6–8 intermediate tubercles, first maxillae with two pairs of lappets; second maxillae with uniformly tapering claws; forcipular coxosternite distinctly wider than long; coxopleural sutures diverging all along their length; chitin-lines incomplete; forcipules relatively short, without denticles, only a small bulge on the base of the tarsungulum; poison calyx elongate; trunk metasternites without carpophagus pit; sternal pore-fields on both anterior and posterior parts of trunk, those on the anterior part including a posterior transverse band, two paired groups just anterior to the latter, and two paired groups at the anterior corners of the metasternite; pores also on procoxae and metacoxae; metasternite of the ultimate leg-bearing segment nearly as long as wide; coxal pores many, scattered, mainly along the margin of metatergite and metasternite; legs of the ultimate pair nearly 2 times longer than the penultimate, swollen in both sexes, with well-developed claws. Table 1 compares the main differential characters among the most similar species of the genus Geophilus .

Description of an adult male ( Figs. 1, 2 , 4, 5 , 8 ). Syntype from Iran, Koohrang mountains (full data in Material and methods) [body entire, not dissected].

General features ( Fig. 1 ). Body 57 mm long, narrowing forward, more attenuated toward the posterior tip. Color (preserved in 70% ethanol) almost uniform, yellow-orange.

Cephalic capsule ( Fig. 2 ). Cephalic plate slightly longer than wide (length/width = ca. 1), sub-trapezoid, lateral margins convex and slightly converging forward, posterior margin concave; transverse suture not evident. Labrum: intermediate part continuous with the clypeus, bearing 6 sclerotised tubercles.

Antennae ( Fig. 2 ). Each antenna ca. 3.6 times as long as the head; article II 1.1 times as long as wide, intermediate articles as long as wide, article XIV ca. 1.5 times as long as wide; setae of various size on the most basal articles, gradually denser and shorter from the basal articles to the distal ones; group of subconic, slender sensilla on articles V, IX and XIII, on both dorso-external and ventro-internal distal position; club-like sensilla on article XIV 5–10 µm long. [Other sensilla impossible to examine, because post-mortem artifacts]

Second maxillae: telopodite composed of three articles, gradually narrowing towards the tip; pretarsus as a simple claw, gradually tapering and slightly curved, without projections.

Forcipular segment ( Fig. 1 ). Forcipules, when closed, almost surpassing the anterior margin of the head. Tergite subtrapezoid, lateral margins evidently converging forward. Coxosternite without denticles; ventrally exposed part 1.5 times as wide as long; coxopleural sutures complete, entirely ventral, distinctly diverging on their anterior half; chitin-lines incomplete, diverging lateral to the condyles. Trochanteroprefemur as long as wide, the external side 2.7 times as long as the internal side. Tarsungulum abruptly narrowing near the base, the distal part curved and tapering uniformly, not flattened, the internal margin entire; a tiny bulge at the base of tarsungulum. No denticles on the other forcipular articles.

Leg-bearing segments. Tergite 1 wider than 2, lateral margins parallel, no distinct pretergite. Metasternites without carpophagus pits on the anterior margin, only intermediate triangular projection on the posterior margin of metasternites of the anterior segments. Ventral pore-fields from segment 1 to the penultimate: pores grouped in a transverse posterior band and four additional paired small groups on the anterior and intermediate part of the metasternite ( Fig. 8 ); pores also on procoxae and metacoxae; pore-fields become smaller and indistinct on the posterior segments. A total of 59 pairs of legs; legs 1 smaller than the other legs; claws with 2 accessory spines.

Ultimate leg-bearing segment ( Fig. 4, 5 ). Pleuropretergite entire, without sutures. Metatergite with lateral margins convex and converging backward, posterior margin truncate. Metasternite sub-trapezoid nearly as long as wide, lateral margins almost straight, posterior margin straight; setae uniformly scattered. Coxal organs opening through distinct pores, each coxopleuron with ca. 21 on ventral and ca. 8 on dorsal side, scattered, but mainly close to the margins of the metatergite and metasternite, without evidently isolated posterior pore. Ultimate telopodite ca. 2.1 times as long as and 2.2 times as wide as the penultimate telopodite; setae uniformly scattered on both dorsal and ventral sides; claws similar to those of precedent legs, but smaller than those, with just one accessory spine, distinctly shorter, on posterior position.

Postpedal segments ( Fig. 5 ). Gonopods bi-articulate, with conical penis in between; a pair of distinct anal organs and pores.

Complementary description of a female ( Figs. 3 , 6, 7, 9, 10 ). From Iran, Mazandaran (full data in Material and methods) [mouth parts dissected].

General features. Body 41 mm long.

Cephalic capsule ( Fig. 6 ). Transverse suture distinct. Clypeus uniformly areolate, without finely areolate clypeal areas and without plagulae; lateral margins complete; 14 pairs of setae arranged in the anterior part of the clypeus, in addition 3 mid-longitudinally aligned setae on the posterior part of clypeus. Labrum: intermediate part continuous with the clypeus, bearing 8 sclerotised tubercles; each lateral part separated from the clypeus by a complete margin, bearing ca. 10 bristles branching into fine short filaments close to the tip. Pleurites uniformly areolate, with 9 anterior setae.

Antennae. Each antenna ca. 3.0 times as long as the head; article II 1.3 times as long as wide, intermediate articles as long as wide, article XIV ca. 2.0 times as long as wide, spine-like sensilla on articles II, XIII and XIV. [Apical sensilla impossible to examine, because antennal tips collapsed]

Mandible. A single pectinate lamella.

Maxillary complex ( Fig. 3 ). First maxillae: coxosternite entire, with short lappets, coxal projections subtriangular, longer than wide; telopodites longer than coxal projections, composed of two articles, with elongate lappets; coxal projections and distal articles of the telopodites bearing setae on the distal part, spine-like sensilla close to the tip and minute scales on the tip. Second maxillae: coxosternite entire, uniformly areolate, anterior margin widely concave, setae close to the anterior margin; metameric pores featuring as transverse slits; telopodite composed of three articles, gradually narrowing towards the tip; claw simple, gradually tapering, slightly bent with 3 sensilla on the ventral side.

Forcipular segment ( Fig. 7 ). Coxosternite: two paramedian groups of 6–7 setae on the dorsal side, close to the anterior margin; ventrally exposed part 1.4 times as wide as long. Trochanteroprefemur nearly as long as wide, the external side 2.1 times as long as internal side. Poison calyx relatively long, 4.2 times as long as wide, lodged in the distal part of trochanteroprefemur.

Leg-bearing segments. A total of 59.

Ultimate leg-bearing segment ( Figs 9–10 ). Coxal organs opening through distinct pores, ca. 22 on ventral and ca. 12 on dorsal side, mainly along the margins of both the metatergite and the metasternite. Ultimate telopodite ca. 2.0 times as long as and 2.2 times as wide as the penultimate telopodite; setae uniformly scattered on both dorsal and ventral sides; claws similar to those of precedent legs but smaller than those, with just one accessory spine, distinctly shorter, on posterior position.

Postpedal segments ( Fig. 9 ). Genital pleurosternite entire, gonopodal lamina distinctly bilobed. A pair of distinct anal organs and pores.

Intraspecific variation. Taking into account the data reported by Attems (1951) (referring to at least four specimens, but the exact number is unclear) and the information acquired directly by us (on one of the syntypes and another 3 specimens), the number of leg pairs varies among specimens of G. g i ga s in the range 51–61, with the highest values 59 and 61 recorded on both males and females, the lowest in a specimen of unknown sex. The transverse suture on the head is either evident or not in different specimens, but this could be affected by preservation condition or by differences in integumental structures during the moulting cycle, different specimens having been fixed at different stages during the inter-moult development. In addition to the common pattern of pore-fields on the metasternites, procoxae and metacoxae, a few pores (1–3) have been detected also on the coxae of the specimens freshly collected from Alborz Mountains, whereas no pores are visible on the coxae of the syntype. However, this apparent difference could be a result of preservation condition after very different times since collection (only 1–2 years vs. more than half a century). Among four adult specimens with well developed gonopods that were studied directly (two males and two females), no sexual dimorphism was found in the ultimate legs, which are similarly swollen in both females and males.

Habitat. Based on published and new data, G. gigas has been recorded from five sites, all in Iran, two from the Zagros Mountains and three from the Alborz Mountains. All sites are in mountainous areas, most sites have semidesertic or grassy vegetation, but one site is covered with highland forest, at high altitude (1500–2600 m), covered by snow during the winter and with cool weather during summer.

Figures

FIGURES 1 – 3. Geophilus gigas Attems, 1951. 1, anterior part of body, ventral; 2, head, dorsal; 3, maxillary complex, ventral. Photos taken from: male syntype from Koohrang, Iran (1 – 2); female from Alborz mountains, Iran (3).

FIGURES 4 – 5. Geophilus gigas Attems, 1951. Ultimate leg-bearing segment and postpedal segments of an adult male: 4, dorsal; 5, ventral. Photos taken from: male syntype from Koohrang, Iran.

FIGURES 6 – 10. Geophilus gigas Attems, 1951. 6, clypeus and labrum, ventral (maxillae removed); 7, forcipular segment, ventral; 8, leg-bearing segment 13, ventral; 9 - 10, ultimate leg-bearing segment and postpedal segments of an adult female, ventral (9) and dorsal (10). Line drawings from: female from Alborz mountains, Iran (6 - 7, 9 - 10); male syntype from Koohrang, Iran (8).