Priscula lumbaqui 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 : 48-56

Priscula lumbaqui Huber sp. nov.

urn:lsid:zoobank.org:act:748651F8-E634-4F74-A11C-B44D27BE59E9

Figs 6E–F , 37–40 , 41B, E , 43B, D–E , 44A

Diagnosis

Easily distinguished from known congeners by extremely widened procursus in lateral view ( Fig. 38C ) and by large triangular sclerite in female internal genitalia ( Fig. 40D ). Also by further details of procursus ( Fig. 38A–C ; distinctive distal sclerite with retrolateral process), genital bulb ( Fig. 38D–F ; main bulbal process shorter than in most congeners, with wide obtuse tip), male chelicerae ( Fig. 39A–B ; very small frontal apophyses – similar only in some Venezuelan species of the limonensis group), and female internal genitalia ( Fig. 40C–D ; pair of processes on ventral arc; pore plates almost round, far apart).

Type material

Holotype ECUADOR – Sucumbíos • ♂; near Lumbaquí ; 0.0349° N, 77.3106° W; 810 m a.s.l.; 30 Sep. 2021; B.A. Huber and M. Herrera leg.; humid forest on hill; MECN–ARAC–48–T .

Paratypes ECUADOR – Sucumbíos • 1 ♀; together with holotype; MECN–ARAC–48–T • 1 ♂, 4 ♀♀ (one female used for SEM); same collection data as for holotype; MECN–ARAC–49–T , in ZFMK Ar 24110 .

Other material examined

ECUADOR – Sucumbíos • 3 ♀♀ (in pure ethanol); same collection data as for holotype; ZFMK Ecu210 .

Etymology

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

Description

Male (holotype)

MEASUREMENTS. Total body length 4.3, carapace width 2.0. Distance PME–PME 240 µm; diameter PME 190 µm; distance PME–ALE 150 µm; distance AME–AME 50 µm; diameter AME 60 µm. ALE larger than PLE and PME (diameter ALE 260 µm). Leg 1: 54.3 (13.5+0.9 +13.3 +23.3 +3.3), tibia 2: 9.3, tibia 3: 6.4, tibia 4: 8.4; tibia 1 L/d: 74.

COLOR (in ethanol). Carapace pale ochre-yellow, with dark ochre median and lateral marks connected by irregular radial lines, ocular area dark ochre to brown, clypeus with large dark ochre band narrowing towards chelicerae; sternum dark ochre with thin brown margins; legs pale ochre, with dark rings on femora (subdistally) and tibiae (proximally and subdistally); abdomen dorsally and laterally densely covered with black marks separated by network of small white marks, ventrally with large brown mark in front of gonopore and ochre to light brown sclerite in front of spinnerets.

BODY. Habitus as in Fig. 6E . Ocular area raised (cf. female: Fig. 41B ), without hump on posterior side, without comb of stronger hairs at median side of each ocular triad. Deep thoracic groove. Clypeus unmodified except sclerotized rim. Sternum wider than long (1.30/0.80), unmodified. Abdomen slightly higher than long, dorso-posteriorly pointed.

CHELICERAE. As in Fig. 39A–B , with short entapophyses, pair of lateral processes proximally and pair of very small frontal apophyses near fang joints; without stridulatory ridges.

PALPS. As in Fig. 37A–C ; coxa unmodified, trochanter slightly protruding ventrally, femur very large, proximally with distinct retrolateral process and indistinct prolateral-ventral process, distal ventral rim not protruding; patella ventrally reduced to strongly sclerotized narrow rim; tibia small relative to femur; procursus ( Fig. 38A–C ) very wide in lateral view, distally with prolateral-dorsal band of whitish membranous and fringed elements, with strongly sclerotized distal sclerite provided with long retrolateral process and apparently moveable against proximal part of procursus; genital bulb ( Fig. 38D–F ) with small proximal sclerite connecting to tarsus, large whitish area on retrolateral-ventral side, strong and curved main bulbal process with wide obtuse tip.

LEGS. Without spines; with very weakly curved hairs on all tibiae and metatarsi; with few short vertical hairs; retrolateral trichobothrium of tibia 1 at 5%; prolateral trichobothrium present on all leg tibiae; tarsi without regular pseudosegmentation but rather with many indistinct platelets.

Male (variation)

Tibia 1 in other male: 12.0.

Female

In general similar to male ( Fig. 6F ) but clypeus slightly less protruding than in male and clypeus rim not sclerotized but with median ochre mark. Ventral sclerite in front of spinnerets variably divided medially or undivided. Tibia 1 in five females: 7.5–8.7 (mean 7.9). Tip of palp simple, pointed, with dorsal invagination ( Fig. 43B ). Tarsal organs on palps and legs exposed ( Fig. 43D, E ). ALS with one strongly widened spigot, one pointed spigot, and one large and four small cylindrical spigots ( Fig. 41E ); with distinctively sculptured area medially in front of ALS (similar to Fig. 41G but smaller). Epigynum ( Fig. 40A–B ) main anterior plate semicircular to trapezoidal, slightly protruding, with pair of low humps at posterior margin, posteriorly medially slightly indented; posterior epigynal plate medially divided by whitish area. Internal genitalia ( Figs 39C , 40C–D ) with pair or oval pore plates, with pair of small processes on ventral arc, and with large median triangular sclerite between pore plates on dorsal arc.

Distribution

Known from type locality only, in Sucumbíos Province, Ecuador ( Fig. 4B ). The ZMH (A2591) has a single female specimen from Napo, “Misahualli via Yuralpa”, 1.0901° S, 77.5434° W, which might belong to this species. In the map in Fig. 4B it is shown as “ P. Dup134”.

Natural history

Most specimens were collected from webs that were hidden deeply in sheltered spaces at ground level; one female was found on the underside of a large dead tree trunk suspended over a brook; one pair was found under small overhangs of a roadcut. One egg-sac had a diameter of 4.5 mm, and contained ~ 65 eggs with an egg diameter of 1.00 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. 37. Priscula lumbaqui Huber sp. nov.; male paratype from near Lumbaqui, ZFMK Ar 24110; left male palp, prolateral, dorsal, and retrolateral views. Scale line: 0.5 mm.

Fig. 38. Priscula lumbaqui Huber sp. nov.; male paratype from near Lumbaqui, ZFMK Ar 24110. A–C. Left tarsus and procursus, prolateral, dorsal, and retrolateral views. D–F. Left genital bulb, dorsal, retrolateral, and ventral views. Abbreviation: ds =distal sclerite. Scale lines: 0.5 mm.

Fig. 39. Priscula lumbaquiHuber sp. nov.; male and female paratypes from near Lumbaqui, ZFMKAr 24110. A–B. Male chelicerae, frontal and lateral views.C. Cleared female genitalia, dorsal view. Scale lines: 0.5 mm.

Fig. 40. Priscula lumbaqui Huber sp. nov.; female paratype from near Lumbaqui, ZFMK Ar 24110. A–B. Abdomen, ventral and lateral views; arrows point at sclerite in front of spinnerets. C–D. Cleared genitalia, ventral and dorsal views; arrows point at processes of ventral arc; asterisk marks distinctive triangular sclerite. 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. 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).