Chthonius stammeri Beier 1942
Creators: name: Gardini, Giulio
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Pseudoscorpiones
Chthoniidae
Chthonius
Chthonius stammeri

description: Chthonius stammeri Beier, 1942
(Figs 387–401, 412)
Chthonius (C.) tenuis ssp. stammeri Beier, 1942: 130 (in part: Grotta di Castelcivita).
Chthonius (C.) stammeri: Gardini & Oggianu 1992: 21–23, figs 12–15.
Type locality: Italy, Campania, Salerno Province, Castelcivita, Grotta di Castelcivita 2 Cp/ SA (40°29’44”N, 15°12’32”E).
Distribution. Italy (Campania).
Diagnosis (♂ ♀). A microphthalmic hypogean Chthonius that differs from other species of the ischnocheles group in the following combination of characters: anterior margin of carapace with 1 (rarely 2) preocular microseta on each side; posterior margin of carapace with 4 macrosetae, lateral setae shorter than the median ones; chelicerae with 3 (rarely 2 or 4) lateral microsetae; chela length 1.09–1.67 mm; movable chelal finger length 0.72–1.09 mm; chelal fingers with reclined, pointed and widely spaced teeth; fixed chelal finger with 41–56 teeth; fixed and movable chelal fingers at level of est -ist and st-t respectively, with 3–5 and 4–6 teeth occupying 0.1 mm, distance between successive apices 0.018 –0.034 and 0.016 –0.030 mm respectively; ratio of pedipalpal femur/carapace 1.5–1.6.
Type material examined. ITALY — Campania: 1 ♀ (lectotype, G. Gardini des., 1991) 2 ♀ (paralectotypes), “ Grotta di Castelcivita bei Salerno [1500– 200 m tief, 3.X.1937], Stammer [leg.], 40, 46” “ Chthonius (C.) tenuis ssp. stammeri nov., Typen, Beier” (NMW).
Other material examined. ITALY — Campania: Salerno Prov. — 2 ♀, Laurino, Grava dell’Occhio (della Costa dei Carpini) n.c. Cp / SA, 1070 m a.s.l., 14.XII.1997, L. Latella & N. Tomelleri leg.; 1 ♂ 2 ♀, id., 3.II.1999, L. Latella & M. Tomelleri leg.; 1 ♂ 3 ♀, Laurino, Grotta dei Fraulusi 202 Cp / SA, 830 m a.s.l., 2.II.1999, L. Latella & N. Tomelleri leg. Basilicata: Potenza Prov. — 1 ♀, Fortino, Grotta De Lorenzo n.c. B/PZ, 5. VIII.1995, L. Latella leg.
Description of adults (♂ ♀). Weak troglomorphic facies; integument pigmented, carapace, tergites, chelicerae and pedipalps reddish brown; hispid granulation on lateral surfaces of carapace, on cheliceral palm, on base of fixed chelal finger and on dorso-distal surface of chelal hand. Carapace (Fig. 389) 0.90–0.95 times longer than broad, trapezoidal, constricted posteriorly; anterior margin denticulate between median macrosetae, with a widely prominent epistome (Figs 387–388); ocular area as in fig. 389, anterior eyes with flat lens (diameter 0.03–0.04 mm), posterior eyes reduced to a cuticular smooth area, distance from anterior eyes to anterior margin of carapace 0.05–0.08 mm; chaetotaxy m 4m:6:4:2:4(22), rarely (2 ♀) anterior row mm 4m, lateral setae of posterior row shorter than the median ones; length of anteromedian macrosetae 0.13–0.20 mm. Chaetotaxy of tergites 4:4:4:4:6:6:6:6:1T2T1:4:1T 2T1:0. Chaetotaxy of sternites II–X: 10:(3)6–10(3):(2)7–10(2):6–8:6:6:6:6:2T1T2, rarely st. II with 9 setae; genital opening of males flanked by 8 setae on each side. Chelicerae (Fig. 390) 2.2–2.3 times as long as broad, palm with 6 (rarely 7) setae and 3 (rarely 2 or 4) lateral microsetae; fixed finger with 2 distal large teeth followed by 8–10 small teeth; movable finger with an isolated subapical tooth (di) at level with the spinneret, followed by a large tooth and 6–9 teeth proximally reduced in size; gs ratio 0.56–0.61; spinneret weakly raised in males and more prominent in females (Figs 390–391); rallum with 11 blades; serrulae interior and exterior with 15 and 17–18 blades respectively. Coxal setae: pedipalp 5 (including 2 on manducatory process), I 3 + 3 marginal microsetae, II 4, III 5, IV 6; coxa II with 11–15 coxal spines, coxa III with 7–9 coxal spines; intercoxal tubercle bisetose. Pedipalp: femur 5.75 (♂) or 5.35–6.2 (♀) times as long as broad, femoral chaetotaxy 3:6:2:5–6:1; chela (Figs 394, 398) 6.2–6.4 (♂) or 5.9–6.3 (♀) times as long as deep; hand of chela 2.1 (♂) or 1.9–2.2 (♀) times as long as deep, with parallel sides (males) or with long ovoid outline in dorsal view (females) (Fig. 392–393); fixed chelal finger with 47–56 (♂) or 41–50 (♀) broad teeth, all cuspidate and inclined backwards in the three distal quarter of the finger, apically rounded in the proximal quarter (Figs 395–397, 399–401), all teeth with dental canal; fixed finger at level of est-it with 4–5 (♂) or 3–4 (♀) teeth occupying 0.1 mm, distance between successive apices 0.018 –0.023 (♂) or 0.023 –0.034 (♀) mm; tip of fixed chelal finger with apical sensilla af 1- 2, distal paraxial seta gradually curved and thin; movable chelal finger with 40–50 (♂) or 40–48 (♀) teeth, reclined and apically pointed in the distal half of the finger, rounded in the proximal half of the finger and increasingly reduced from sb towards finger base (Figs 395–397, 399–401); movable finger at level of st-t with 6 (♂) or 4–5 (♀) teeth occupying 0.1 mm, distance between successive apices 0.016 –0.018 (♂) or 0.022 –0.030 (♀) mm; coupled sensilla pc at level or just distad of sb; tip of movable chelal finger with apical sensilla am 1- 2; trichobothria as in figs 394, 398; ratio sb -st/sb -b = 1.65–1.85; ratio of movable finger/hand of chela 1.9–2.15; ratio of pedipalpal femur/movable finger 0.95–1.0; ratio of pedipalpal femur/carapace 1.5–1.6.
Measurements (in mm). Body length 1.7 (♂) or 2.0–2.5 (♀). Carapace 0.47–0.49 × 0.51–0.52 (0.49–0.51 anteriorly) (♂) or 0.58–0.70 × 0.65–0.74 (0.63–0.72 anteriorly) (♀). Chelicerae 0.50–0.51 × 0.215–0.22 (♂) or 0.63–0.76 × 0.285–0.34 (♀); movable finger length 0.275–0.28 (♂) or 0.345 –0.405 (♀). Pedipalp: femur 0.72–0.75 × 0.125– 0.13 (♂) or 0.9–1.11 × 0.17–0.195 (♀); chela 1.09–1.15 × 0.175–0.18 (♂) or 1.39–1.67 × 0.235–0.27 (♀); hand length 0.37–0.38 (♂) or 0.47–0.58 (♀); movable finger length 0.72–0.79 (♂) or 0.92–1.09 (♀).
Remarks. Chthonius tenuis stammeri was described by Beier (1942) based on four females from the Cave of Castelcivita (Salerno) and compared with C. cephalotes (Simon, 1875). In the same paper Beier attributed some specimens collected by Stammer (25.IX.1937) in the Zinzulusa Cave (Apulia) to C. tenuis stammeri, arguing that these represent a transitional form because they have anterior eyes with lens and reduced posterior eyes, while in stammeri they are all absent (augenlos: Beier 1942). The population of Zinzulusa Cave was later described by Caporiacco (1951a) from specimens that had been collected by C. Conci and S. Ruffo (3.X.1948) as Chthonius (Globochthonius) ruffoi (see Remarks under C. densedentatus).
Chthonius stammeri was elevated from a subspecies of C. tenuis by Beier (1961) who recorded it from the Chiusazza Cave (Syracuse, Sicily) and later Beier (1963a) considered both stammeri and ruffoi as subspecies of C. ischnocheles, correcting the previous identification of C. stammeri for specimens from the Chiusazza Cave (C. ischnocheles ruffoi sensu Beier 1961). Shortly after Chthonius stammeri was upgraded from a subspecies of C. ischnocheles by Beier (1963b) and ruffoi was considered a subspecies of C. stammeri.
Gardini & Oggianu (1992) redescribed both Chthonius stammeri and C. ruffoi from original types and specimens collected from the type locality. They recognized both as valid species, emphasizing the similarity between C. stammeri and C. ischnocheles.
Among the species of the Chthonius ischnocheles group, C. stammeri is most similar to C. ischnocheles, an epigean species present also in the same geographic area, from which it differs in most troglomorphic characters: surface of carapace, cheliceral palm and chelal hand with weak hispid granulation (with marked scale-shaped granulation in C. ischnocheles), anterior eyes reduced or at most with flat lens, posterior eyes reduced to a cuticular smooth area (anterior eyes with convex, posterior ones with flat lens in C. ischnocheles), ratio of movable finger/hand of chela 1.9–2.15 (1.6–1.9 in C. ischnocheles).
The above description of Chthonius stammeri incorporates that of Gardini & Oggianu (1992).
The distribution map (Fig. 412) also shows the record of the Pertosa Cave (Mahnert 1980), located 21 kilometers in a straight line from Castelcivita Cave, the type locality of Chthonius stammeri.
description: Published as part of Gardini, Giulio, 2021, The Italian species of the Chthonius ischnocheles group (Arachnida, Pseudoscorpiones, Chthoniidae), with reference to neighbouring countries, pp. 1-131 in Zootaxa 4987 (1) on pages 120-123, DOI: 10.11646/zootaxa.4987.1.1, http://zenodo.org/record/4979653