Typhlonesticus angelicus Isaia and Ribera, 2023

Isaia, Marco, Nicolosi, Giuseppe, Infuso, Alessandro & Ribera, Carles, 2023, Two new subterranean Typhlonesticus (Araneae: Nesticidae) from the Alps with notes on their ecology, distribution and conservation, Arthropod Systematics & amp; Phylogeny 81, pp. 801-818 : 801

3.3.1. Typhlonesticus angelicus Isaia and Ribera sp. nov.

Figs 2A-E , 5A, C , 7A

Examined material.

Holotype: ITALY, Piemonte, Province of Cuneo: Chiusa di Pesio, Grotta Superiore delle Camoscere [Pi 250], 44.2183°N, 7.6605°E (Fig. 7D ), 1200 m a.s.l., 3.XII.2018, Isaia M. and Mammola S. leg. 1f (MCSNB) (sub " Typhlonesticus morisii " in Isaia et al. 2017: 323) . - Paratypes: same locality as holotype, 15.VII.1987, Comotti G. and Baldan A. leg. 1f (MCSNB) • 3.XII.2018, Isaia M. and Mammola S. leg. 1 juv. (CI) • Liguria, Province of Imperia : Triora , Prospetto di Miniera del Monte Grai , 43.99650°N, 7.67296°E, 1878 m a.s.l., 12.VIII.2016, Beikes S. and Isaia M. leg. 1f (CI) • Roccaforte Mondovì, Grotta dei Partigiani della Tura [Pi 286], 44.24081°N, 7.73308°E, 1780 m a.s.l., 18.VIII.2016, Giachino P.M. and Lana E. leg. 1m • FRANCE, Alpes Maritimes: Brigue, Bunker Opera 34, Balconi di Marta, 44.01534N, 7.64178°E, 1914 m a.s.l., 12.VIII.2016, Beikes S. and Isaia M. leg. 1m, 2juv. (CI) (all material cited (sub " Typhlonesticus morisii " in Isaia et al. 2017: 323) . - Other material: ITALY, Piemonte, Province of Cuneo: Roccaforte Mondovì, Grotta dei Partigiani della Tura [Pi 286], 44.24081°N, 7.73308°E, 1780 m a.s.l., 22.V.2016, Chesta M. and Lana E. leg. 1f (CI) • same locality, 7.VI.2016, Chesta M. and Lana E. leg. 1m, 2f, 1 juv. (CI) • same locality, 25.VI.2016, Chesta M. and Lana E. leg. 1f (CI) • same locality, 18.VIII.2016, Giachino P.M. and Lana E. leg. 3m, 1juv. (CI) • Roccaforte Mondovì, Grotticella della Tura [Pi n.c.], in the vicinity of Pi 286, 25.VI.2016, Chesta M. and Lana E. leg. 1f (CI) • same locality, 12.VIII.2016, Chesta M. and Lana E. leg. 2m, 1f, 2 juv. (CI) (all material cited sub " Typhlonesticus morisii " in Isaia et al. 2017: 323) .

Diagnosis.

Males of the new species differ from Typhlonesticus morisii by the shape and the arrangement of the paracymbial apophyses, mainly the ventral one, which is straight in T. angelicus sp. nov. ( “vp” in Fig. 2D, E ) and distally bent in T. morisii (Fig. 4D, E ). Subtle differences are also found in the shape of p1 and p2 processes (Figs 2D , 5C ) and the shape of the median apophysis ( “ma” in Figs 2D , 5C ). - Females of T. angelicus sp. nov. are best diagnosed by the orientation of the insemination ducts (Figs 2A, B , 5A ), not twisted and connecting directly to the spermathecae ventrally rather than dorsally, such as in T. morisii (Figs 4A, B , 5H ).

Description of the female.

Female holotype from Grotta superiore delle Camoscere [Pi 250], 3.XII.2018, Isaia M. and Mammola S. leg. - Coloration: Carapace pale yellow. Head region of the same color. Sternum yellow brown, without pattern. Opisthosoma grey-white without pattern. Legs same color as carapace. - Prosoma: Carapace 1.70 long, 1.42 wide, cephalic region not differentiated from the rest of the carapace. Clypeus height under AME 0.302. Labium as long as wide or moderately wider than long. Sternum 0.97 long, 0.86 wide. Eyes reduced and depigmented, no corneal lenses are visible. Both eye rows recurved in dorsal view PER 0.52 wide, AER 0.36. AME reduced to a small spot of pigment. Eye diameter: AME 0.03, ALE 0.05; PME 0.05; PLE 0.05. - Opisthosoma: 2.37 long, 1.80 wide. Total length 4.07 (4.25 including spinnerets). Leg formula: I>II>IV>III. Epigynal plate 0.35 long, 0.47 wide. Epigyne convex and prominent, without sclerotized plates (Figs 2A , 5A ). The posterior edge is slightly sclerotized. Spermathecae and insemination ducts can be observed through the tegument. Vulva simple (Figs 2B , 5A ), consisting of two small spermathecae, insemination and fertilization ducts. Insemination ducts coiled, forming one lap around the fertilization ducts before reaching the spermatheca. Vulval pockets absent (Fig. 2A, B ). - Appendages: Chelicerae 0.58 long, 0.31 wide, with 3 equally spaced teeth on promargin and 18-20 very small teeth grouped on retromargin. - Leg measurements: Leg I: femur 4.13, patella 0.82, tibia 4.01, metatarsus 3.82, tarsus 1.59, total 14.37. Leg II: femur 3.42, patella 0.68, tibia 3.03, metatarsus 2.99, tarsus 1.31, total 11.43. Leg III: femur 2.63, patella 0.59, tibia 2.05, metatarsus 2.17, tarsus 0.94, total 8.39. Leg IV: femur 3.63, patella 0.75, tibia 3.07, metatarsus 2.63, tarsus 1.13, total 11.21. Palp: femur 1.07, patella 0.32, tibia 0.63, tarsus 1.09, total 3.11.

Description of the male paratype.

Paratype from Roccaforte Mondovì, Grotta dei Partigiani della Tura [Pi 286], 1780 m a.s.l., 44.24081°N, 7.73308°E, 18.VIII.2016, Giachino P.M. and Lana E. leg. - Coloration: Carapace yellow brown. Sternum yellow brown, without pattern. Head region of the same color. Opisthosoma grey-white without pattern. Legs same color as prosoma, all trochanters notched. - Prosoma: Carapace 1.66 long, 1.54 wide. Carapace approximately circular in dorsal view. Cephalic region not differentiated from the rest of the carapace. Clypeus height under AME 0.39. Labium as long as wide or moderately wider than long. Sternum 1.07 long, 1.06 wide. Reduced and depigmented eyes. No corneal lenses visible. Both eye rows recurved in dorsal view, PER 0.54 wide, AER 0.31. Eye diameter: AME 0.04, ALE 0.05; PME 0.05; PLE 0.05. - Opisthosoma: 2.63 long, 1.50 wide. Total length 4.29 (4,51 including spinnerets). Leg formula: I>II>IV>III. - Appendages: Chelicerae: 0.91 long, 0.33 wide, with 3 equally spaced teeth on promargin and 18-20 very small teeth grouped on retromargin. Leg formula: I>II>IV>III - Male palp (Fig. 2D, E ): Paracymbium short, with a well-developed ventral process consists of a long and flattened lamella, curved towards the apex and tapering and a dorsal one consisting of a short laminar apophysis, ending in a rounded and enlarged lobe directed toward the ventral one (Figs 2D, E , 5C ). Conductor complex with two well developed processes (p1 and p2): p1 longer than wide in lateral view (Fig. 5C ), tapering in the distal third; p2 is in an apical position and ends with two convergent apical hooks running as a conductor for the embolus. Embolus filamentous following a semi-circular course towards the apex and bordering the tegulum (Figs 2D , 5C ). Large and well-developed median apophysis, ventrally directed, wider at its base and narrower at its medial-final part, cone-shaped with a blunt end (Fig. 2D ). - Leg measurements: Leg I: femur 4.57, patella 0.79, tibia 4.66, metatarsus 4.42, tarsus 1.57, total 16.01. Leg II: femur 4.48, patella 0.81, tibia 4.52, metatarsus 4.35, tarsus 1.52, total 15.68. Leg III: femur 3.25, patella 0.74, tibia 2.74, metatarsus 2.92, tarsus 1.16, total 10.81. Leg IV: femur 4.42, patella 0.80, tibia 3.97, metatarsus 3.65, tarsus 1.39, total 14.23. Palp: femur 1.16, patella 0.28, tibia 0.44, tarsus 0.75, total 2.63.

Etymology.

The species is dedicated to Angelo Morisi (1943-2016) beloved Piedmontese natural scientist, expert in reptiles, amphibians, cave-dwelling invertebrates, freshwater macroinvertebrates, fishes and lichens. Angelo was a kind-hearted, altruist and caring natural scientist, pioneer of the biospeleological research in Piedmont, and first collector of several rare troglobiont species that still carry his name, including Typhlonesticus morisii , sister species of T. angelicus sp. nov. The specific epithet is in form of adjective and conjugates the name of Angelo and the features of benevolent immortal beings with a translucent body of light, barely visible to the human eye.

Distribution, sampling notes and ecology.

Typhlonesticus angelicus sp. nov. is restricted to subterranean habitats of the central portion of Alpi del Marguareis, within the section of Alpi Liguri (Fig. 6 ). Five isolated populations are known so far, covering an area of approximately 100 km2 spanning from the upper Maudagna Valley (two nearby populations) and mid-Pesio Valley (one population) in the north to the border of Italy and France in the south (two populations). The population of Balconi di Marta (Brigue), formerly assigned to T. morisii and now re-assigned to T. angelicus represents the only record of Typhlonesticus for France, leaving T. morisii as uniquely known from Italy (Vernante). All caves open in Alpine grasslands at 1,800-2,000 m a.s.l., with the exception of the designed type locality Pi 250 - Grotta Superiore delle Camoscere (Pesio Valley) (Fig. 7D ) opening at the upper limit of a beech forest, approximately at 1,200 m a.s.l. - Several renown Italian biospeleologists, including Angelo Morisi himself and Gianni Comotti, the first collector in history of a female specimen of this new species, visited this cave through time leading to the discovery of an extraordinary and highly specialized community of subterranean endemic arthropods, including Troglohyphantes vignai Brignoli, 1971 ( Araneae : Linyphiidae ), Leptoneta crypticola Simon, 1907 ( Araneae : Leptonetidae ), Holoscotolemon oreophilum Martens, 1978 ( Opiliones : Travuniidae ) ( Isaia et al. 2011, 2022) and the rare subterranean beetle Agostinia launoi (Gestro, 1892) ( Carabidae , Trechinae ). - Individuals of T. angelicus sp. nov. were preferably found on cave walls and to a lesser extent on the cave ground, hanging upside down on their criss-cross web or walking on vertical rocks (Fig. 7A ), mostly hidden in rock fissures. Females may be found throughout the year, while males appear to be very rare. All caves inhabited by T. angelicus sp. nov. are characterised by constant high relative humidity close to saturation. - Typhlonesticus angelicus sp. nov. prefers the medium alpine montane belt (mean = 1,693 m; n = 4) and inhabits sites characterised by mean annual temperatures from 4.1 to 9.1°C (mean = 5.7°C; range: 5.0; n = 4), colder than T. morisii being uniquely found in Sotterranei di Vernante, where the temperature ranges from 8.3 to 9.8°C during the year.

Conservation status and basic information for an IUCN Red List assessment. Range description, Area of Occupancy (AOO) and Extent of Occurrence (EOO).

The species is endemic to Alpi del Marguareis over an altimetric range of approximately 700 m (min-max elevation 1,200-1,914 m a.s.l.) (Fig. 6 ). Five populations are known so far (four if considering the two nearby localities in Roccaforte Mondovì as one), encompassing an estimated AOO of 16 km2 and an EOO of 103 km2. We infer a decline in both EOO and AOO because of global warming due to the sensibility of troglobionts to increasing global temperature (see Mammola et al. 2019a). Dispersal ability for this species is not known but given the high development of troglomorphic characters and the restricted range, it is assumed to be very low. - Locations: In the Red List criteria, “location” refers to a threat-based area and is different from the general notions of locality. In fact, the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. Global warming is expected to affect all known populations of T. angelicus sp. nov., consequently, one single location should be considered for the assessment risk of this species. - Threats: The species is potentially exposed due to its extremely narrow geographic distribution range, its low dispersal capacity and its inferred low thermic tolerance related to the high level of troglomorphism. - Conservation actions: Considering the ongoing global warming, it is worth considering the extinction risk of T. angelicus sp. nov. As very little is known about the biology and life history of this species, to date it is not possible to provide any precise management actions. However, the inclusion of this species on the IUCN Red List represents an important starting point for its conservation. As seen for other subterranean systems of conservation concern for red listed and legally protected species, three out of five caves hosting T. angelicus sp. nov. benefit from being included in protected area or Sites of Conservation importance, namely IT1160056 (Alpi Marittime) and IT1160057 (Alta Valle Pesio and Tanaro). - Note on the conservation status in France: T. morisii has been cited in “CR” status in the Red List of Spiders in France since the beginning of 2023 ( Bounias-Delacour et al., 2023). Its new distribution and its replacement at the French locality of Balconi di Marta by T. angelicus , would give the latter the same status in France.

Figures

Figure 2. Typhlonesticus angelicus sp. nov., holotype female from Chiusa di Pesio, Grotta Superiore delle Camoscere [Pi 250] (Isaia M. and Mammola S. leg., 3. XII. 2018) (A, B, C) and paratype male from Grotta dei Partigiani della Tura [Pi 286] (Giachino P. M. and Lana E. leg., 18. VIII. 2016) (D, E). Epigyne in ventral view (A), vulva in dorsal view (B), female cephalothorax in frontal view (C), left male pedipalp in ventral view (D) and male cymbium in dorsal view (E) (see section 2.2.3. for abbreviations). Scale bars 0.2 mm.

Figure 4. Typhlonesticus morisii (Brignoli), female from type locality, Vernante, Sotterranei del Forte A di Vernante Opera 11, Tetto Ruinas [Art. Pi CN] (Isaia M., Nicolosi G. leg., 25. III. 2022) (CI) (A, B, C) and holotype male from same locality, Morisi A. leg., 14. X. 1972 (D, E). Epigyne in ventral view (A), vulva in dorsal view (B), female cephalothorax in frontal view (C), left male pedipalp in ventral view (D) and male cymbium in dorsal view (E) (see section 2.2.3. for abbreviations). Scale bars 0.2 mm.

Figure 5. The four Italian species of Typhlonesticus: photographs of vulvae (A, B, E, F) and left male pedipalps in prolateral view (C, D, G, H). A, C Typhlonesticus angelicus sp. nov.; B, D Typhlonesticus santinellii sp. nov.; E, G Typhlonesticus idriacus (Roewer); F, H: Typhlonesticus morisii (Brignoli).

Figure 6. Distribution of Typhlonesticus in Italy.

Figure 7. Live specimens of Typhlonesticus angelicus sp. nov. (A male), T. morisii (Brignoli) (B female) and T. santinellii sp. nov. (C female) in their natural habitats. The entrance of Grotta superiore delle Camoscere [Pi 250], type locality of T. angelicus sp. nov. (D), the military bunker of Sotterranei di Vernante, type locality of T. morisii (Brignoli) (E, F); the walls of " Galleria del Pozzo' ' within the mining complex of Gorno, type locality of T. santinellii sp. nov. (G); the entrance of Murdosso cave [Lo BG 7407], where the first female of T. santinellii sp. nov. was collected during the unblocking operations of the cave conducted by the local speleological groups " Underland " and " I Tassi " (H).