Centromerus hanseni, Ballarin & Pantini, 2020

Ballarin, Francesco & Pantini, Paolo, 2020, Three new species and new records of the genus Centromerus (Araneae, Linyphiidae) from Italy, European Journal of Taxonomy 660 (660), pp. 1-23 : 8-11

Centromerus hanseni sp. nov.

urn:lsid:zoobank.org:act:DABE9924-06A9-4ED5-9CA8-F4246BCD9902

Figs 3–4 , 10

Diagnosis

Males of the new species generally resemble male Centromerus tongiorgii sp. nov., C. semiater and C. sellarius . They can easily be separated from males of the other three species by the presence of a welldeveloped radical apophysis I (RA-I) which is clearly visible when the palp is observed prolaterally or retrolaterally, in contrast to the absent or non-visible RA-I in males of the other three species. A further diagnostic character is the square, stocky dorsal hump (DT) of male C. hanseni sp. nov., which appears triangular and ending with a sharp or rounded tip in the other three species. In addition, male C. hanseni sp. nov. can easily be separated from male C. tongiorgii sp. nov. and C. semiater by the presence of a well-developed apophysis in the distal part of the paracymbium (APC), clearly visible when the palp is observed ventrally ( Fig. 4C ), absent in the other two species.

The epigyne of female C. hanseni sp. nov. is similar to that of female C. tongiorgii sp. nov., C. isaiai and C. sylvaticus . However, female C. hanseni sp. nov. can be distinguished by the narrower and truncated anterior wall (AW); the other species have a wider AW, always ending with a sharp or lobate tip. The different shape of the posterior median plate (PMP) further distinguishes these species, as the PMP is squared in C. hanseni sp. nov., but, in contrast, rectangular in C. tongiorgii sp. nov., triangular in C. isaiai and trapezoid in C. sylvaticus (see Figs 3G , 4E vs Figs 1G , 2E vs Bosmans & Colombo 2015: fig. 13 and Wiehle 1956: fig. 55). In addition, the small size of both males and females easily separates the new species from the large majority of other species of Centromerus , which generally show a larger body size.

Etymology

The specific name is a patronym in honor of Harald Hansen, an Italian arachnologist from Venice who recently passed away ( Uliana 2018). Hansen widely contributed to the study of the Italian spider fauna, in particular the family Salticidae .

Material examined

Holotype

ITALY • ♂; Calabria Region, Cosenza, Fagnano Castello, Trifoglietti Lake ; 39.5489° N, 16.0229° E; 1050 m a.s.l.; Aug. 2016 – May 2017; beechwood, in the litter; pitfall traps; M. Valle leg.; MSNB.

Paratypes

ITALY – Calabria Region • 1 ♀; same locality as for holotype; Aug. 2013 – Aug. 2014; M. Valle leg.; MSNB • 3 ♂♂, 2 ♀♀; same locality as for holotype; Aug. 2014 – May 2015; M. Valle leg.; MSNB • 2 ♀♀; same locality as for holotype; Aug. 2015 – Aug. 2016; M. Valle leg.; MSNB • 1 ♂, 1 ♀; same locality as for holotype; Aug. 2016 – May 2017; M. Valle leg.; MSNB • 1 ♂; Reggio Calabria, Bagaladi, Nucarelle ; 38.0553° N, 15.812° E; 1100 m a.s.l.; Nov. 2013 – Jun. 2014; beechwood; pitfall traps; E. Castiglioni and F. Manti leg.; MSNB • 4 ♂♂; Reggio Calabria, San Luca, Serra Juncari ; 38.1559° N, 15.9367° E; 1750 m a.s.l.; Nov. 2013 – Apr. 2014; mixed wood with beech ( Fagus sylvatica ), juniper ( Juniperus communis ) and pine trees ( Pinus sp.); pitfall traps; E. Castiglioni and F. Manti leg.; MSNB.

Description

Male

HABITUS. See Fig. 3H.

MEASUREMENTS. Total length 1.55–2.05. Carapace 0.71 long, 0.52 wide.

PROSOMA. Carapace uniformly yellowish, chelicerae, labium and gnathocoxae of the same color. Chelicera with stridulatory ridges on the lateral margin. Three teeth at the anterior margin of the fang groove, posterior margin with 4–5 small denticles. Sternum greyish.

ABDOMEN. Greyish with 3–4 V-shaped lighter stripes, sometimes reduced to simple marks barely visible in some specimens.

LEGS. Uniformly yellowish. Femur I with 1 prolateral spine. Tibial spine formula: 2221. TmI: 0.25. Leg measurements as follows: I: 0.73 + 0.23 +0.68 +0.52 +0.38 (2.54), II: 0.67 +0.23 + 0.58 +0.47 +0.38 (2.33), III: 0.55 + 0.21 +0.47 +0.43 +0.35 (2.01), IV: 0.75 +0.21 +0.66 +0.56 +0.37 (2.56).

PALP ( Figs 3 A–D, 4A–C). Patella and tibia bearing one robust spine each, tibia with 3 trichobothria. Cymbium with a stocky, squared dorsal hump. Paracymbium large, with a robust, pointed apophysis headed outward on the distal part, lateral margin covered with several minute wrinkles. Two proximal radical apophyses, one robust, spine-like, the other long, thin and thread-like, both curved outward and downward. Distal radical apophysis with several minute denticles. Distal suprategular apophysis robust and curved outward, second branch shorter. Antero-proximal part of median membrane with a row of 9–10 small, stumpy teeth. Terminal apophysis transparent and scarcely visible, ending with a wide, flat and wrinkled tip. Embolus curved, ending in a sharp point.

Female

HABITUS. See Fig. 3I.

MEASUREMENTS. Total length 1.7–1.9. Carapace 0.82 long, 0.67 wide.

PROSOMA AND ABDOMEN. As in male. Abdomen with more marked and wider light stripes.

LEGS. As in male. Leg measurements as follows: I: 0.56 +0.22 +0.46 +0.35 +0.34 (1.92), II: 0.51 + 0.18 + 0.40 + 0.34 + 0.30 (1.72), III: 0.42 + 0.18 + 0.31 + 0.31 + 0.27 (1.49), IV: 0.59 +0.17 + 0.51 +0.39 +0.31 (1.96).

EPIGYNE AND VULVA ( Figs 3 E–G, 4D–E). Anterior wall triangular and strongly wrinkled, covering a large epigynal cavity, ending with a truncated, squared tip. Distal part of scapus wide, strongly protruding from the epigynal cavity. Posterior median plate large and rectangular, wider than longer. Spermathecae small, comma-like. Copulatory grooves first turning posteriorly and outward before returning to the middle part of the vulva and ending in copulatory openings at the distal part of the scapus.

Distribution

Endemic to Italy. Distributed along the Calabrian Apennine mountain range, see Fig. 10 .

Figures

Fig. 3. Centromerus hanseni sp. nov., from Trifoglietti Lake. A. Male palp, retrolateral view. B. Ditto, prolateral view. C. Ditto, ventral view. D. Ditto, dorsal view. E. Epigyne, ventral view. F. Ditto, lateral view. G. Vulva after maceration, dorsal view. H. Male habitus. I. Female habitus.

Fig. 4. Centromerus hanseni sp. nov., from Trifoglietti Lake. A. Male palp, retrolateral view. B. Ditto, prolateral view. C. Ditto, ventral view. D. Epigyne, ventral view. E. Vulva, dorsal view.

Fig. 10. Distribution in the Italian peninsula of the species C. tongiorgii sp. nov. (= red dots); C. hanseni sp. nov. (= azuretriangles); C. gatoi sp. nov. (= yellow diamonds); C. cf. paradoxus (Simon, 1884) (= green pentagons); C. desmetiBosmans, 1986 (= violetstar); C. succinus (Simon, 1884) (= dark bluesquares).

Fig. 1. Centromerus tongiorgii sp. nov., from Grezzana. A. Male palp, retrolateral view. B. Ditto, prolateral view. C. Ditto, ventral view. D. Ditto, dorsal view. E. Epigyne, ventral view, F. Ditto, lateral view. G. Vulva after maceration, dorsal view. H. Male habitus. I. Female habitus.

Fig. 2. Centromerus tongiorgii sp. nov., from Endine Gaiano. A. Male palp, retrolateral view. B. Ditto, prolateral view. C. Ditto, ventral view. D. Epigyne, ventral view. E. Vulva, dorsal view.