Centetostoma ventalloi ( Mello-Leitao, 1936 )

Martens, Jochen, 2011, The Centetostoma scabriculum complex — a group of three cryptic species (Arachnida: Opiliones: Nemastomatidae), Zootaxa 2783, pp. 35-51 : 41-47

Centetostoma ventalloi ( Mello-Leitao, 1936)

Figs 1–2 , 5–6 , 11 , 19, 23–29

Nemastoma ventalloi Mello-Leitao 1936: 9 ; Kraus 1961: 344; Rambla 1980: 198.

Material investigated. The type and other material originally deposited in the Natural History Museum of Barcelona are apparently lost (C. Ribera pers. comm. to A. Schönhofer). Paratypes in the Rio de Janeiro Museum of Natural History (see Mello-Leitao 1936: 10) have been inspected.

Type material. 13 paratype, SPAIN. Prov. Lleida (Lérida), Val d’Aran, D. Ventalló leg., date unknown ( MNRJ 42538); 13 paratype, same data ( MNRJ 42545).

Further material investigated. FRANCE. 23, Midi-Pyrénées, Dép. Hautes-Pyrénées, SW Lannemezan, above Fabian, valley of Neste de Couplan, 1550 m, N 42.783° E 0.216°, J. Martens leg. 30.8.1978 (CJM 1775); 13, Dép. Ariège, near St. Girons, 15km SE of Castillon, Col de la Core, 1400 m, N 42.854° E 1.103°, J. Martens leg. 31.8.1967 (CJM 752); 1Ƥ, same locality, 1400–1450 m, under stones in open pasture, N 42.854° E 1.103°, A. Schönhofer leg. 10.10.2009 ( CAS 635); 13, Dép. Ariège, S of Couflens, Cirque d´Anglade, 1450 m, N 42.74° E 1.20° J. Martens leg. 19.8.1978 (CJM 1687); 53 1Ƥ, Dép. Ariège, S of Massat, Etang de Lers, in light forest, 1450 m, N 42.883° E 1.333°, J. Martens leg. 22.9.1979 (CJM 2567); 13, Dép. Ariège, SW Foix, below Col de Péguère, 1300 m, N 42.916° E 1.383°, J. Martens leg. 17.8.1978 (CJM 1789); 13 (together with 113 10Ƥ C. juberthiei sp. n.; see below), Dép. Pyrénées-Orientales, SW Quillan, Lac des Bouillouses, 1900-2100 m, N 42.716° E 1.983°, J. Martens leg. 20.6.1972 (CJM 6844); 13, Dép. Pyrénées-Orientales, Prats-de-Mollo-la-Preste, NE Col d’Ares, bor- der of open pasture and Pinus forest, 1501 m, N 42.375° E 2.456°, A. Schönhofer leg. 2.10.2009 ( CAS 597, together with 263 18Ƥ C. juberthiei sp. n., see below); – SPAIN. 13, Cataluña, Prov. Lleida (Lérida), N Pico Maladeta, S Las Bordas (Es Bòrdes), Artiga de Lin, river gorge, 1200 m, N 42.733° E 0.7°, J. & B. Martens leg. 1.9.1984 (CJM 2654); 173 10Ƥ, Cataluña, Prov. Lleida (Lérida), Val d’Aran, Artiga de Lin, 1500-1900 m, N 42.678° E 0.705°, A. Schönhofer leg. 3.- 4.10.2009 ( CAS 589); 23, Cataluña, Prov. Lleida (Lérida), SE Viella, Puerto de Bonaigua, open slope with gravel, grass, 2000 m, N 42.683° E 0.733°, J. & B. Martens leg. 30.8.1984 (CJM 2645); 53, same locality, under stones in alpine pasture, 2050-2200 m, N 42.663° E 0.98°, A. Schönhofer leg. 3.10.2009 ( CAS 581); 63 2Ƥ, Cataluña, Prov. Lleida (Lérida), SE Viella, SE Puerto de Bonaigua, 1400 m, Abies forest, N 42.663° E 0.981°, J. & B. Martens leg. 29.8.1984 (CJM 2642).

Taxonomy. Centetostoma ventalloi was tentatively synonymised with scabriculum by Kraus (1961) which was supported by Rambla (1980). However, based on genital morphology, form of male apophysis of chelicerae and lack of a spur on patella of the palp, C. ventalloi clearly represents a species of its own.

Diagnosis. A Pyrenean species of Centetostoma . Apo of male basichelicerite deeply split at medial side ( Fig. 6 ); without spur on palpal patella medio-distally ( Figs 19, 23 ); wings on penial truncus broadest of any species within the genus ( Figs 11 , 24–29 ).

Measurements (3, Ƥ in parentheses): Leg II: Fe 1.1 (1.1), Pt 0.3 (0.3), Ti 0.8 (0.8), Mt 1.4 (1.4), Ta 1.2 (1.2). Body length: 1.3–1.55, n=3 (1.5–1.7, n=3). Span of truncus wings: 0.22–0.24 (n=6, Figs 24–29 ).

Description. Body ( Fig. 2 ): Body narrows towards front, to the rear end slightly enlarged laterally, most significant at rear third. Entirely black in adults several weeks (to months) after final moult to adulthood; older adult specimens encrusted with a thin layer of secretion which – at least after storage in alcohol – is opaque whitish and more or less camouflages the sculpture of the body’s surface.

Dorsal scutum ( Fig. 2 ): With a distinct armature of well-defined button-like tubercles, quite large and positioned in only moderately regular rows. Along an imaginary median line from the rear end of the eye mound to the rear end of the dorsal scutum there are about 20 individual tubercles; intermediate space between tubercles less than tubercle’s diameter. Rear end of scutum with a saw-like row of acute longish tubercles, their end slightly rounded; this, too, holds true for the two free tergites. On area I–V of the dorsal scutum one pair each of larger, slightly broader and higher tubercles than the tubercle ground coverage, the inter-distances of these tubercle pairs slightly enlarging towards the rear end of the scutum.

Tuber oculorum ( Fig. 2 ): Its anterior end on the front margin of the dorsal scutum; irregularly armed with two longer (antlers-like, front) to shorter (middle and rear) blunt tubercles.

Supracheliceral lamellae ( Fig. 2 ): Split into several longish and upwards-extended comb-like structures, each tooth armed with a short spiny brush on top.

Chelicerae ( Figs 5–6 ): Male, basal segment dorso-distal with a large frontad-directed knotty Apo ( Fig. 5 ), medio-dorsally (lateral and medial view) somewhat incised forming a shallow saddle ( Fig. 5 ). In dorsal view, this Apo is deeply indented, the curvature forming a narrow triangle separating a distal and a proximal part of the Apo ( Fig. 6 ). In medial view the top of the Apo slightly projects over to the medial side resulting in a deep depression in the inner part of the Apo ( Fig. 5 right). The Apo is armed with few spines medially, the lateral and dorso-distal side of the basal segment irregularly armed with short strong spines ( Fig. 5 ). Female: as in the male, but no Apo present on the basal segment.

Pedipalps ( Figs 19, 23 ): Moderately compact. Fe to Ta covered with sparse (Fe) to more dense (Pt, Ti, Ta) array of bristles, most of them are clavate glandular setae, sparse on Fe and Ti, more dense on Ti and Ta. There is no medial spur on the distal end of Pt in both sexes.

Legs: Short in terms of nemastomatid morphology. Fe, Pt and Ti of leg I markedly inflated, less so in legs III and IV, leg II slender and un-inflated, all segments of legs I and III–IV with low and small tubercles causing an irregularly rugged surface. Pseudoarticulations of femora I–IV (3, Ƥ in parentheses): I 0 (0), II 3–4 (3–4), III 2–3 (2), 3– 4 (3–4).

Ventral side: Operculum genitale and free sternites with scattered small tubercles, in a row on the free tergites, more densely packed on the sternites of the corona analis; coxae pro- and retro-lateral with a scattered row of 6–8 blunt tubercles each.

Genital morphology ( Figs 11 , 24–29 ): Truncus penis extremely thin and slender, at the basis bulb-like inflated and medially incised. Distad of the truncus bulb narrowed (dorsal/lateral view), from about half length slightly but continuously broadened towards the lateral wings. Lower contour line of the individual wing is oblique, the upper one horizontal with a slight upward turn. In the scabriculum complex wing span is largest in ventalloi (see Measurements). Glans is continuously tapering to the pointed stylus, the latter not well differentiated, and to the opening of the seminal duct.

Variability: Male genital morphology is subject to some variation. It is most obvious in the truncus wings below the glans: Its span over the lateral tips differs slightly. The single wing may be more compact ( Figs 25, 27 ) or more slender ( Figs 26, 29 ), straight ( Figs 24, 29 ) or curved upwards ( Figs 26, 28 ). There is no overlap in wing span measurements between C. ventalloi and C. scabriculum (see below).

Distribution ( Fig. 1 ). Type locality is in the Spanish Province of Lérida, in the Vallée d’Aran (Val d’Aran), from where the species was recently re-collected (see Material). Further fresh material originates from a relatively small area on the French side of the Pyrenees from the départements of Hautes-Pyrénées (western-most record: SW Lannemezan, valley of Neste de Couplan river) to Ariège and Pyrénées-Orientales (eastern-most record: Lac des Bouillouses, SW Quillan). Most localities originate from Ariège, where the species apparently has its strongholds. There is a considerable area overlap with C. juberthiei sp. n.

Ecology. Eight records for altitudinal distribution range from 1200–2000 m (vertical belt 800 m), among them five from 1400–1550 m. Most records originate from light forests and clearings in forests, under stones and decaying wood. The only locality from 2000 m is from a rock-covered slope with low grass and herbs. Adults appear all year round and regularly overwinter. At one occasion (CAS 589) a number of specimens were found walking freely on mossy upper parts of large beech tree roots at night (A. Schönhofer pers. comm.).

Figures

FIGURE 1. Pyrenean distribution of Centetostoma scabriculum (squares, blue), C. ventalloi (dots, green) and C. juberthiei sp. n. (triangles, red). Note two sympatric occurrences of C. ventalloi and C. juberthiei sp. n. with overlaying symbols. The western-most overlaying symbols (scabriculum / juberthiei sp. n.) represent the type locality of C. scabriculum (Saint-Sauveur) and denote a false record for C. juberthiei sp. n.

FIGURES 2 – 4. Dorsal side of body, ♂. 2: Centetostoma ventalloi (Col de la Core, CJM 752). 3: C. scabriculum (Torla, CJM 1799). 4: C. juberthiei sp. n. (Lac des Bouillouses, CJM 1792).

FIGURES 5 – 10. Right 3 chelicerae. 5, 7, 9: lateral (left column) and medial view (right column); 6, 8, 10: dorsal view. 5 – 6: Centetostoma ventalloi (Col de la Core, CJM 1792). 7 – 8: C. scabriculum (Torla, CJM 1799). 9 – 10: C. juberthiei sp. n. (Lac des Bouillouses, CJM 1792).

FIGURES 11 – 13. Penes, dorsal view. 11: Centetostoma ventalloi (SW Foix, CJM 1789). 12: C. scabriculum (Col d’Aubisque, CJM 3918). 13: C. juberthiei sp. n. (Col de Port, CJM 1726).

FIGURES 19 – 23. Pedipalps of 3, medial view. 19, 23: Centetostoma ventalloi (19: Val d’Aran, MNRJ 42545, paratype; 23: Lac des Bouillouses, CJM 6844). 20 – 21: C. scabriculum (20: Torla, CJM 1799, 21: Saint Sauveur, SMF 967). 22: C. juberthiei sp. n. (Lac des Bouillouses, CJM 1792).

FIGURES 24 – 29. Centetostoma ventalloi, glandes penis, dorsal view. 24: Péguère (CJM 1789). 25: Cirque d’Anglade (CJM 1687). 26: Neste de Couplan (CJM 1775). 27: Val d’Aran (MNRJ 42545, paratype). 28: Val d’Aran (MNRJ 42538, paratype). 29: Col de la Core (CJM 752).