Phrynus perrii

Description. Female (Holotype): Length, 8.1 mm. Carrying six embryos. Carapace, chelicera, palps and legs pale brown, unpigmented; cuticle weakly sclerotized. Carapace: Slightly concave in frontal region. Anterior margin bilobed, corners flattened down, with several setae (Fig. 1 A). Frontal process triangular; slightly wider than long and may not be seen in dorsal view because of its slight curvature facing inward. Median eyes underdeveloped, smaller in diameter than lateral eyes (Figs. 1 A and 1 D); ocular tubercle reduced (Fig. 1 D). Lateral eyes with lenses flattened, without pigmentation and with one seta posterior to each triad. Carapace mostly unpigmented, chelicerae can be observed through the carapace. Sternum: Tri-segmented, second and third segments non-sclerotized and slightly convex; tritosternum projected anteriorly, elongated, conical, with one pair of apical setae, one medial seta, one pair of basal setae, and with two small setae on posterior margin (Fig. 1 B). Second segment (tetrasternum) rounded, with one seta at each anterior corner. Third segment (pentasternum) rounded and slightly smaller than second, with one seta at each anterior corner. Metasternum divided longitudinally, with two small setae on posterior margin of each half. Gonopods: Genital operculum margin slightly bilobed. Gonopods stinger-like, longer than wide; separated from one another by less than 0.2 mm (Fig. 1 E). Chelicera: Basal segment of chelicera with three inner teeth; distal tooth bifid, proximal cusp larger than distal. Teeth length: III> Ib> Ia> II. Basal segment of chelicera with one tooth on external margin of retrolateral surface (Fig. 1 C). Claw with 5 denticles. Pedipalp: Trochanter: Prolateral face with 4 marginal spines; spines Tr 1 and Tr 3 located near the medial region, Tr 2 located closer to ventral margin than others, Tr 3 and Tr 4 subequal in length (Figs. 2 A, 2 C). Trochanter spine length: Tr 2> Tr 1> Tr 4> Tr 3. Dorsal oblique series of 5 setal tubercles (Fig. 2 A). Femur: Dorsal portion with several setae; six major dorsal spines (no minor spines are observed on the right femur), the spines Fd 1 and Fd 2 out of the same base, spine lengths: Fd 3> Fd 2 = Fd 5> Fd 1> Fd 6> Fd 4, on left pedipalp with one minor spine distal to Fd 6. Ventral portion with six major spines (Fig. 2 D): Fv 1> Fv 2> Fv 3 ≈ Fv 5> Fv 6> Fv 4. Fv 3 is just slightly larger than Fv 5; on right femur one minor spine is observed after Fv 5, with less than half the size of Fv 4; whereas left femur has two minor spines, one between Fv 3 - Fv 4, the second is inconspicuous and is distal to Fv 6. Patella: Dorsal portion with eight major spines (Fig. 2 E): Pd 3> Pd 5 ≈ Pd 2> Pd 4> Pd 6> Pd 7> Pd 1> Pd 8; two minor spines on right patella; one between Pd 1 - Pd 2 the other between Pd 4 - Pd 5. Left patella has an additional minor spine between Pd 5 - Pd 6. Pd 2 is about 1 / 3 longer than Pd 4. Pd 6 is twice the size of Pd 7 and there is an inconspicuous spine distal to Pd 7 (= Pd 8). Ventral portion with seven major spines (Fig. 2 G): Pv 5> Pv 2> Pv 4> Pv 6> Pv 1> Pv 3> Pv 7. Pv 3 is slightly longer than Pv 7; Pv 4 is slightly longer than Pv 6. Right patella with a minor spine between Pv 5 - Pv 6, whereas left patella also has a minor spine between Pv 1 - Pv 2. Tibia: Dorsal portion with three major spines (Fig. 2 F), with setae on their bases and spinules; spine lengths: Td 2> Td 3> Td 1. Td 1 is less than half-length of Td 2. Four minor spines: two between Td 2 - Td 3, at the base of Td 3; other two are distal to Td 3. Ventral portion with three major spines (Fig. 2 H): Tv 2> Tv 1> Tv 3; one minor spine between Tv 2 - Tv 3, and an inconspicuous spine basal to Tv 1. Tarsus + Apotele: Inner face with two dorsomedial lines of bristles, dorsoventral suture between tarsus and apotele not visible. Tarsus without an inconspicuous spine on proximal end of dorso-inner lateral surface. Legs: All densely setose. Femur lengths: I> III> IV> II. Leg I: Tibia with 27 segments and tarsus with 64 segments in the right leg; left leg has 31 segments in the tibia and 79 segments in the tarsus. Leg IV: Basitibia with 3 segments. Basitibia-distitibia lengths: BT 1> DT> BT 3> BT 2. Basitarsus slightly longer than telotarsus. Tarsus tetramerous. Female (Paratype): Similar to holotype, except: right palp femur with a minor spine between Fv 3 - Fv 4 (also with a minor spine between Fv 5 - Fv 6, like the holotype); patella has only one minor spine between Pd 1 - Pd 2 on the right pedipalp, whereas left has two minor spines, one basal to Pd 1 and the other distal to Pd 1; tibia has two minor spines on the right pedipalp, one basal to Td 1 and second between Td 2 - Td 3; left tibia presents 3 minor spines, two between Td 2 - Td 3 and one distal to Td 3; right leg I with 27 and 68 segments in the tibia-tarsus respectively (segment tibia-tarsus left leg I is missing).

Diagnosis. Phrynus perrii differs from most species of Phrynus, except. P. noeli Armas and Perez 1994, by presenting small median eyes on a nearly obsolete ocular tubercle. Differs from P. no e l i on the coloration of the reduced ocular tubercle, black in P. n oe l i, whereas on P. perrii it is the same color as the carapace (pale brown). In addition, the new species differs from other species of Phrynus by having the following combination of characters: chelicera with only one tooth on external margin of retrolateral surface (P. no e l i has three teeth); Tv 1 longer than Tv 3; Fd 2 shorter than Fd 3; tarsus with two dorsomedial lines of bristles, and the dorso-internal lateral surface without a small spine; only Phrynus hoffmannae Armas & Gadar, 2004, shares the above features with P. perrii, however, in P. hoffmannae the eyes are not reduced and are pigmented, Fd 2 and Fd 3 are almost the same length, Pd 2 is shorter or equal to Pd 4 and visibly shorter than Pd 3, whereas on P. perrii Fd 3 is almost twice longer than Fd 2, Pd 2 is longer than Pd 4 and almost with the same length of Pd 3.

Discussion. Few organisms considered troglomorphic are really troglobites, this is further complicated when the ecology of organisms is unknown. Although most species of Phrynus can be found in caves (Weygoldt, 2000), they don´t show any troglomorphisms and are considered troglophyles and trogloxenes. Only Phrynus noeli was described as a troglobitic species by Armas & Perez (1994), because it was collected in a cave in western Cuba and shows adaptive characters to cavernicolous environment; however subsequently in two opportunities it has been found in epigean environments near the cave entrance, under rocks, in a similar habitat to a cave (“ Hoyo de los Helechos ”) (Armas, 2006 b), consisting of a very small, deep valley between the mountains, were the bottom does not get direct sunlight, it is cool and humid and the vegetation is mostly ferns (partly reminiscent of the first living habitat of a cave) (personal communication, Armas, 2014). Therefore, this species, although it is troglomorphic, should be considered a troglophile rather than a troglobite (sensu Racovitza, 2006). The new species described here was collected in the deep zone of the cave where there are no circadian fluctuations in temperature, and with the subterranean river flowing through the cave the relative humidity is almost constant throughout the year. Furthermore, the presence of troglomorphic features such as the ocular tubercle nearly obsolete and the small size of median eyes, the lack of pigmentation, and reduced sclerotization suggest a close association of P. perrii to the cave environment. In addition, environmental conditions outside the cave are very different than in the depths, with marked seasonality in temperature and rainfall making it unlikely for this species to survive outside the cave. However, further collection efforts in and around the cave are needed in order to correctly assess the ecological association of this species to the cave environment. Remarks. Phrynus noeli is cited as the only species in the genus with elongation of the legs (Armas & Perez, 1994), a common troglomorphisms in troglobitic arthropods, and the authors used this as another argument to support their initial interpretation that it is a troglobitic species adapted to the cavernicolous environment. However, comparisons with other species of the genus revealed no differences in the relative length of the appendices among other species of Phrynus, including Phrynus perrii. Something similar happens within the genus Paraphrynus, comparing between epigean versus troglomorphic species, watching only a slight difference in the elongation of appendages of some of the troglomorphic species. Nevertheless, examining material from the type localities of Paraphrynus chacmool and Paraphrynus chiztun not exhibit an elongation proportionately longer in contrast to the author of both species mentioned, “ The limbs, notably the first walking legs, are also proportionately longer ” (Rowland, 1973). This happens often with troglobitic species descriptions, mentioning the elongation of these appendages, where no comparative reference is given (see, Cokendolpher & Sissom, 2001; Baptista & Giupponi, 2002; Baptista & Giupponi, 2003). Hence, in amblypygids, the elongation of the appendages is not useful for assessing adaptation to caves, i. e., it does not appear as a distinctive troglomorphism. It is possible that leg length in amblypygids is under the same selective pressures inside and outside the caves, and an increase in leg length in troglobites would not make them any faster in their escape responses or in their prey-catching efforts.

Distribution. Known only from the type locality (Fig. 3) Natural history. The cave is located in Middle Cretaceous limestone beds, and inside the cave is a subterranean river; the cave did not show any human disturbance. The specimens were collected approximately 500 m inside a horizontal cave, collected manually on the floor and walls, active for three hours. Other arachnids collected inside the cave were; Pseudoscorpions, Ricinoididae (Pseudocellus sp.), Pholcidae, Hubbardiidae (Stenochrus portoricensis), Phrynidae (Paraphrynus emaciatus) and Argasidae (Ornithodoros sp.). During a visit to the cave in the previous year, no troglomorphic amblypygids were found; however, a sampling of the area outside the cave produced scorpions (Centruroides chiapanensis and Diplocentrus sp.), jumping spiders (Salticidae) and whip spiders (Phrynus operculatus). The habitat outside the cave is cropland, pasture and some remnants of tropical deciduous forest.

Etymology. The species is dedicated to Gerardo A. Contreras-Felix, a. k. a. as “ Perri ”, for his help collecting the types and for his contribution to the knowledge of Mexican scorpions.

Type material. MEXICO: Chiapas: Municipio Cintalapa: Cueva del Naranjo (16.854667 ° N, 93.704528 ° W, 769 masl, 500 m into the cave), 30 March 2014, G. Contreras & G. Montiel leg., holotype female (CNAN-T 0864). Paratype: same data as holotype, 1 female (CNAN-T 0865).