Priscula pastaza Huber, 2023

Huber, Bernhard A., Meng, Guanliang, Dupérré, Nadine, Astrin, Jonas & Herrera, Mauricio, 2023, Andean giants: Priscula spiders from Ecuador, with notes on species groups and egg-sac troglomorphism (Araneae: Pholcidae), European Journal of Taxonomy 909, pp. 1-63 : 38-42

Priscula pastaza Huber sp. nov.

urn:lsid:zoobank.org:act:DADCE77E-4843-45FC-B14E-B20C35764BE3

Figs 6A–B , 29–32 , 41A, C, H , 42D–E, H , 43C, G–H , 44B–D, F

Diagnosis

Distinguished from known congeners by details of procursus ( Fig. 30A–C ; tip with two large membranous elements: wide dorsal flap and long ventral flap with pointed tip), genital bulb ( Fig. 30D– F ; main bulbal process weakly curved with obtuse tip), epigynum ( Fig. 32A–B ; semicircular, longer than in putatively closest known relatives, P. esmeraldas sp. nov. and P. chapintza sp. nov.), and female internal genitalia ( Fig. 31C ; round pore plates similar to P. chapintza but not connected to sclerites posteriorly).

Type material

Holotype ECUADOR – Pastaza • ♂; Cavernas del Anzu Forest Reserve, Caverna de los Continentes ; 1.4067° S, 78.0449° W; 1160 m a.s.l.; 25 Sep. 2021; B.A. Huber and M. Herrera leg.; in cave; MECN–ARAC– 37–T .

Paratypes ECUADOR – Pastaza • 1 ♂, 2 ♀♀ (one female used for SEM); same collection data as for holotype; MECN–ARAC–38–T , in ZFMK Ar 24101 .

Other material examined

ECUADOR – Pastaza • 3 ♀♀, 2 juvs (in pure ethanol); same collection data as for holotype; ZFMK Ecu174 • 2 ♂♂ (one palp used for SEM), 1 ♀, 2 juvs; Cavernas del Anzu Forest Reserve, Cueva Copa del Mundo ; 1.4054° S, 78.0433° W; 1140 m a.s.l.; 26 Sep. 2021; B.A. Huber and M. Herrera leg.; in cave; MECN–ARAC–39–T , in ZFMK Ar 24102 • 1 ♀ with egg-sac; same collection data as for preceding; MECN–ARAC–40–T , in ZFMK Ar 24103 • 1 juv. (in pure ethanol); same collection data as for preceding; ZFMK Ecu183 • 1 ♀, 2 juvs; same locality as for preceding; 17 Jul. 2013; M. Archambault leg.; QCAZ .

Etymology

The species name is derived from the type locality, noun in apposition.

Description

Male (holotype)

MEASUREMENTS. Total body length 4.2, carapace width 1.7. Distance PME–PME 200 µm; diameter PME 130 ×150 µm; distance PME–ALE 50 µm; AME absent (cf. female: Fig. 41A ). ALE and PLE larger than PME (diameter ALE 180 µm, PLE 160 µm). Leg 1: 41.4 (10.3+0.8+ 10.4 +17.5 +2.4), tibia 2: 7.7, tibia 3: 5.7, tibia 4: 7.3; tibia 1 L/d: 69.

COLOR (in ethanol). Carapace light-brown, with whitish marks beside ocular area, clypeus with large light brown band narrowing towards chelicerae; sternum light brown with thin darker brown margins; legs monochromous light brown, without darker rings; abdomen monochromous pale gray, only ventrally with darker ochre mark in gonopore area.

BODY. Habitus as in Fig. 6A . Ocular area raised, without hump on posterior side, with comb of stronger hairs at median side of each ocular triad. Deep thoracic groove. Clypeus unmodified except sclerotized rim. Sternum wider than long (1.15/0.80), unmodified. Abdomen globular to slightly higher than long, dorso-posteriorly rounded.

CHELICERAE. As in Fig. 31A–B , with short entapophyses, pair of short frontal apophyses close to fang joints; without stridulatory ridges.

PALPS. As in Fig. 29A–C ; coxa unmodified, trochanter slightly protruding ventrally, femur large, with unsclerotized retrolateral process proximally followed distally by sclerotized indentation, distal ventral rim not protruding; patella ventrally reduced to strongly sclerotized narrow rim; tibia small relative to femur; palpal tarsal organ exposed, weakly raised ( Fig. 43C ); procursus ( Fig. 30A–C ) with distinct whitish protruding area dorsally, distinctive prolateral and dorsal membranous elements composed of hair-like processes (dorsal part shown in Fig. 42D–E ), distal ventral sclerite flat and weakly sclerotized; genital bulb ( Fig. 30D–F ) with small proximal sclerite connecting to tarsus, with large whitish area on retrolateral-ventral side, strong and slightly spiraling main bulbal process with subdistal sperm duct opening (arrow in Fig. 42H ) and obtuse tip.

LEGS. Without spines; with curved hairs on tibiae and metatarsi (mainly legs 1 and 2); with few short vertical hairs; retrolateral trichobothrium of tibia 1 at 6%; prolateral trichobothrium present on all leg tibiae; tarsi without regular pseudosegmentation but rather with many indistinct platelets.

Male (variation)

Tibia 1 in three other males: 9.3, 11.0, 11.3. AME pigment always present but lenses tiny (~20 µm diameter) or absent.

Female

In general similar to male ( Fig. 6B ) but clypeus rim not sclerotized and hairs on ocular area unmodified. AME variable as in males. Tibia 1 in five females: 7.7–8.8 (mean 8.2). Tarsal organs exposed ( Fig. 43G–H ); main tarsal claws with ~14–17 tines, tarsus 4 claws more evenly curved and with shorter tines than tarsi 1–3 claws ( Fig. 44C–D, F ). ALS with one strongly widened spigot, one pointed spigot, and one large and four small cylindrical spigots ( Fig. 41C ); with distinctively sculptured area medially in front of ALS ( Fig. 41H ). Epigynum ( Fig. 32A–B ) main anterior plate semicircular, slightly protruding, posteriorly with lighter semicircular area; posterior epigynal plate medially divided by whitish area. Internal genitalia ( Fig. 31C ) with simple sclerotized arc, membranous ‘valve’, and pair or roundish pore plates.

Distribution

Known from two neighboring caves in the Cavernas del Anzu Forest Reserve, Pastaza Province, Ecuador ( Fig. 4B ).

Natural history

All spiders were collected in the interior of two caves; adults were only found in the aphotic zones, but juveniles were also found in the twilight area (the first meters of the entrance areas of both caves were occupied by a different species that also occurs in the neighboring forest; see P. bonita sp. nov.). No specimens of P. pastaza sp. nov. were found in the well-preserved neighboring forest, suggesting that the species might be a troglobite, i.e. strictly bound to underground habitats. The spiders were hanging in very fine and barely visible webs, freely exposed among rocks or in wall niches. Two egg-sacs contained six and seven eggs, respectively, with an egg diameter of 0.95 mm.

Figures

Fig. 6. Priscula spp., binghamae and andinensis groups, live specimens. A–B. P. pastaza Huber sp. nov.; male and female with egg-sac from Cavernas del Anzu Forest Reserve. C–D. P. bonita Huber sp. nov.; male from La Bonita-Santa Barbara and female with egg-sac from Gruta de los Tayos. E–F. P. lumbaqui Huber sp. nov.; male and female from near Lumbaqui.

Fig. 29. Priscula pastaza Huber sp. nov.; male paratype from Cavernas del Anzu Forest Reserve, ZFMK Ar 24101; left male palp, prolateral, dorsal, and retrolateral views. Scale line: 0.5 mm.

Fig. 30. Priscula pastaza Huber sp. nov.; male paratype from Cavernas del Anzu Forest Reserve, ZFMK Ar 24101. A–C. Left tarsus and procursus, prolateral, dorsal, and retrolateral views; asterisks: whitish protruding area. D–F. Left genital bulb, dorsal, retrolateral, and ventral views. Scale lines: 0.5 mm.

Fig. 31. Priscula pastaza Huber sp. nov.; male and female paratypes from Cavernas del Anzu Forest Reserve, ZFMK Ar 24101. A–B. Male chelicerae, frontal and lateral views. C. Cleared female genitalia, dorsal view. Scale lines: 0.5 mm.

Fig. 32. Priscula pastaza Huber sp. nov.; female paratype from Cavernas del Anzu Forest Reserve, ZFMK Ar 24101. A–B. Abdomen, ventral and lateral views. C–D. Cleared genitalia, ventral and dorsal views. Scale lines: 0.5 mm.

Fig. 41. Priscula spp., SEM photographs of female ocular areas and spinnerets. A–B. Ocular areas, frontal views; Priscula pastaza Huber sp. nov. (A) and P. lumbaqui Huber sp. nov. (B). C–E. ALS, P. pastaza (C), P. esmeraldas Huber sp. nov. (D), and P. lumbaqui sp. nov. (E). F–H. Distinctive structures in front of spinnerets (in place of colulus); P. chapintza Huber sp. nov. (F), P. esmeraldas (G), and P. pastaza (H). Scale lines: 100 µm (A–B); 10 µm (C–G); 2 µm (H).

Fig. 42. Priscula spp., SEM photographs of male pedipalps. A–C. Tip of left procursus in dorsal view (A) and hair-like processes on its prolateral (B) and retrolateral (C) sides; P. esmeraldas Huber sp. nov. D–E. Tip of left procursus in retrolateral view (D) and hair-like processes in more detail (E); P. pastaza Huber sp. nov. F–G. Left procursus and bulb of P. bonita Huber sp. nov., showing position of tarsal organ (arrow in F) and position of sperm duct opening (arrow in G). H. Sperm duct opening (arrow) on bulbal process in P. pastaza. Scale lines: 100 µm (A, F–G); 10 µm (B–C, E); 20 µm (D, H).

Fig. 43. Priscula spp., SEM photographs of female palps and of male and female tarsal organs. A–B. Tips of female palps in dorsal views; Priscula esmeraldas Huber sp. nov. (A) and P. lumbaqui Huber sp. nov. (B). C. Male palpal tarsal organ, P. pastaza Huber sp. nov. D. Female palpal tarsal organ, P. lumbaqui. E–H. Female tarsal organs on leg 1 (E, P. lumbaqui), leg 2 (F, P. esmeraldas), leg 3 (G, P. pastaza), and leg 4 (H, P. pastaza). Scale lines: 10 µm (A, C–F); 20 µm (B); 2 µm (G–H).

Fig. 44. Priscula spp., SEM photographs of female legs. A–B. Oval plates of unknown function, in Priscula lumbaqui Huber sp. nov. (A, metatarsus 4) and P. pastaza Huber sp. nov. (B, metatarsus 4). C–F. Tarsal claws of leg 1 (C, P. pastaza), leg 2 (D, P. pastaza), leg 3 (E, P. bonita Huber sp. nov.), and leg 4 (F, P. pastaza). G. Microstructure of claw tines (P. chapintza Huber sp. nov.). H. Basis of mechanoreceptive hair (P. chapintza; metatarsus 4), showing distal bulge (on right side). Scale lines: 10 µm.

Fig. 4. Known distribution of Priscula in Ecuador. A. Representatives of the gularis group. Circles: P. gularis (TL=type locality) and specimens treated herein as “P. gularis?” and “P. cf. gularis”. Squares: other Ecuadorian representatives of the gularis group. B. Representatives of the andinensis group (red) and binghamae group (blue) in Ecuador. The background colors indicate biogeographic regions of Ecuador (as far as relevant for Priscula, i.e., Andean regions from western foothill forests to eastern foothill forests), taken from Torres-Carvajal et al. (2019).