Pseudocellus giribeti, Valdez-Mondragón & Cortez-Roldán, 2021

Valdez-Mondragón, Alejandro & Cortez-Roldán, Mayra R., 2021, COI mtDNA barcoding and morphology for the description of a new species of ricinuleid of the genus Pseudocellus (Arachnida: Ricinulei: Ricinoididae) from El Triunfo Biosphere Reserve, Chiapas, Mexico, European Journal of Taxonomy 778, pp. 1-25 : 10-18

Pseudocellus giribeti sp. nov.

urn:lsid:zoobank.org:act:685BFED1-4CC2-4DD4-BA1F-E829799BE8C7

Figs 3‒35

Differential diagnosis

Pseudocellus giribeti sp. nov. resembles Pseudocellus alux Armas & Agreda, 2016 . However, several morphological differences distinguish both species. The opisthosoma of the male of P. giribeti sp. nov. is shorter and slightly oval ( Fig. 1 ), whereas that of P. alux is slightly longer and less oval ( Armas & Agreda 2016: fig. b). The carapace in the new species is as short as in P. alux ( Figs 3, 5 ). Males of the new species have the tibia of the pedipalp deeply curved on the prolateral part ( Fig. 19 ), whereas in P. alux the tibia of the pedipalp is slightly curved ( Armas & Agreda 2016: fig. c). Males of P. giribeti sp. nov. and P. alux have a similar shape of femur II, but the males of the new species have a longer femur II than P. alux , with proportions of 3.45 and 2.17 times as long as wide, respectively ( Fig. 17 ; Armas & Agreda 2016: figs b, f). Males of P. giribeti sp. nov. and P. alux have a similar shape of tibia II, with two basal conical apophyses on tibia II, one proventral and the other retroventral ( Figs 3–4 , 13–14 ); however, in P. giribeti sp. nov. the tubercles are thinner and located at ⅓ of the tibia length ( Figs 13–14 ), whereas in P. alux the tubercles are wider and with a sharp tip, located at almost ½ of the tibia length ( Armas & Agreda 2016: fig. f). The tarsal process (tP) of male leg III of P. giribeti sp. nov. is slightly wider and less curved than in P. alux ( Figs 21, 23, 25 ; Armas & Agreda 2016: fig. e). The tip of the tP is bifurcated in both species, but in the new species the lobule 1 (L1) is longer and thinner than in P. alux ( Fig. 26 ; Armas & Agreda 2016: fig. e). The metatarsal process (mP) of males of P. giribeti sp. nov. is wider distally than in P. alux ( Figs 20–21 ; Armas & Agreda 2016: figs d–e). The lamina cyathiformis (Lc) of males of the new species is wide and straight dorsally ( Figs 20–21 ), whereas in P. alux it is thinner and slightly curved dorsally ( Armas & Agreda 2016: figs d–e). Unfortunately, the spermathecae in P. alux were not dissected in the original description by Armas & Agreda (2016), and therefore it is not possible to compare both species in this regard.

Etymology

This species is dedicated to Dr Gonzalo Giribet from Harvard University in recognition of his contribution to the knowledge of ricinuleid phylogenetics and the loan of the specimens.

Type material

Holotype MEXICO • ♂; Chiapas, Campamento El Quetzal , Reserva de la Biosfera El Triunfo , Mpio. Angel Albino Corzo ; 15.7221° N, 92.9429° W; 1820 m a.s.l.; 20 May 2008; R. Anderon leg.; MCZ 80010.

Paratypes MEXICO • 14 ♂♂, 10 ♀♀, 6 deutonymphs, 4 tritonymphs; same collection data as for holotype; MCZ 80010 • 1 ♂, same collection data as for holotype; CNAN-T01482 • 1 ♀; same collection data as for holotype; CNAN-T01483 .

Description

Male (holotype, MCZ 80010)

Specimen collected manually, preserved, and observed in 80% ethanol.

MEASUREMENTS (mm). Total length (carapace + opisthosoma including pygidium) 3.55. Carapace 1.30 long, 1.32 wide (widest part). Cucullus 0.60 long, 0.90 wide. Opisthosoma 2.36 long (not including pygidium), 1.68 wide (widest part). Femur II length/diameter (l/d): 3.17. Legs, tarsal formula (leg I to IV): 1-5-4-5. Leg lengths; I: coxa 0.60/ trochanter 1 0.32/ trochanter 2 -/ femur 0.80/ patella 0.42/ tibia 0.66/ metatarsus 0.76/ tarsus 0.40/ total 3.96; II: 0.70/ 0.48/ -/ 1.32/ 0.72/ 1.08/ 1.12/ 1.25 / 6.67; III: 0.62/ 0.33/ 0.37/ 0.90/ 0.50/ 0.57/ 0.68/ 1.09/ 5.06; IV: 0.56/ 0.38/ 0.33/ 0.95/ 0.50/ 0.62/ 0.72/ 0.76/ 4.82. Leg length formula: 2-3-4-1.

COLORATION. Cucullus, carapace and sternal region dark reddish ( Figs 3‒6 ). Legs I, III and IV lighter dark reddish than legs II; tarsomeres paler reddish than other segments. Opisthosoma reddish dorsally, darker ventrally on sternites XI and XII ( Figs 7–8 ).

CARAPACE ( Fig. 5 ). Slightly longer than wide, trapezoidal, widest at posterior margin between coxae II and III. Tegument covered with abundant, fine translucent setae and granules. Anterior margin straight, lateral margins not parallel, narrowing anteriorly; posterior margin procurved. Inconspicuous translucent areas present at level of trochanters II. Carapace with seven depressions: one median along, and three lateral depressions at level of each coxae III.

CUCULLUS ( Fig. 11 ). As wide as long, widest distally; anterior margin straight, lateral margins rounded at anterior corners. Tegument covered with abundant translucent setae and granules similar to those on carapace. One slight depression each side close to anterior margin, cuticular pits absent. Distal margin with long, translucent setae.

CHELICERAE ( Fig. 12 ). Movable finger with eight teeth, basal one larger than others, which are equal in size. Fixed finger with five teeth, subequal in size, distal tooth longer. Both fingers with long translucent setae basally.

STERNAL REGION ( Fig. 6 ). Coxae covered with translucent setae and granules similar to those on carapace. Coxae I rhomboidal, II sub-rectangular, III and IV conical. Coxae II larger and wider than others, coxae IV smallest. Coxae II meeting tritosternum along ⅓ of its length. Coxae II anterior and posterior margins perpendicular to median axis of prosoma; coxae III slightly oblique, their posterior margins forming an obtuse angle (>90°) with each other; coxae IV oblique, their posterior margins forming an obtuse angle (little more>90°) with each other.

OPISTHOSOMA ( Figs 3–4 , 7–8 ). Longer than wide, widest at level of tergites XII and XIII. Tegument covered with abundant setae and granules similar to those on carapace; cuticular pits absent. Median plates of tergites XI–XIII with paired longitudinal depressions, those of tergite XI the smallest. Tergite X widest and shortest. Median tergites XI and XII trapezoidal, wider than long; median tergite XIII slightly longer than wide, with posterior corners curved. Lateral tergites in oblique position; X smallest and XIII largest. Lateral tergites XI trapezoidal, XII square and XIII triangular. Sternites XI–XIII with paired depressions. Sternites XI and XII dark medially, XIII paler reddish. Pygidium segments without notch ( Fig. 10 ).

PEDIPALPS ( Figs 6 , 18–19 ). Coxae with fine translucent setae and rounded granules. Trochanters 1 rounded, with sparse fine translucent setae and few granules restricted to ventrodistal half; trochanters 2 conical, ventrally with basal setae and granules (similar to those on 1 st). Femora curved distally and wider proximally, without granules, with deep prolateral concavity distally close to tibial joint; tegument with abundant translucent setae, thinner and longer on prolateral and distal surfaces. Tibiae deeply curved on prolateral part, with numerous thin translucent setae longer distally. Tibiae without granules. Movable claws curved and longer than fixed claws, which are conical. Movable claws without teeth, fixed claws with small teeth.

LEGS. Without cuticular pits but with translucent setae and rounded granules on all segments ( Figs 3–4 ). Legs II noticeably longer and wider ( Figs 3–4 ). Femora II almost straight, slightly curved on prolateraldistal part, wider and longer than the others; femora II ventrally with few scattered sharp-tipped granules ( Fig. 17 ). Tibiae II ventrally with two sharp and small apophyses on basal part ( Figs 3–4 , 13–14 ). Metatarsus II with scattered sharp-tipped granules, not forming rows, ventral ones longer and more conspicuous than dorsal one, metatarsus curved ventrally ( Figs 15–16 ). Tarsomeres of leg II dorsally with sharp-tipped granules, tarsomeres 5 with fewer granules not sharp-tipped. Femora I, III and IV ventrally with few sharp-tipped granules. Patellae I, III and IV with normal granules. Tibiae I, III and IV ventrally with few sharp-tipped granules distally. All metatarsi dorsally with V-shaped invaginations distally; metatarsi I, III and IV without granules ventrally, only few slightly sharp-tipped granules dorsodistally on metatarsi I and IV. Tarsomeres of legs I, III and IV without granules.

LEGS III AND COPULATORY APPARATUS. Metatarsi almost square-shaped in prolateral view, with numerous long translucent setae; metatarsal processes (mP) long and slightly sigmoidal in pro and retrolateral views ( Figs 20–21 ), curved and hook-shaped in dorsal view ( Fig. 22 ). Lamina cyathiformis (Lc) of tarsomeres 2 leaf shaped, with a small notch basally in retrolateral view ( Fig. 20 ), Lc with long translucent setae throughout. All tarsomeres ventrally with long translucent setae, which are more numerous and longer on tarsomere 4. Tarsomeres 4 with two curved claws ( Figs 20‒22 ). Copulatory apparatus sigmoid shaped in dorsal view ( Fig. 24 ), with tarsal process (tP) curved, arc-shaped ( Figs 23, 25 ); accessory piece (ac) of copulatory apparatus curved, with sharp tip ( Fig. 23 ). Tip of the tP bifurcated, with a long and conical lobule 1 (L1) ( Fig. 26 ).

Female (Paratype, MCZ 80010)

Specimen collected manually, preserved and observed in 80% ethanol. MEASUREMENTS. Total length (carapace + opisthosoma including pygidium) 3.70. Carapace 1.32 long, 1.44 wide. Cucullus 0.60 long, 0.87 wide. Opisthosoma 2.46 long (not incluiding pygidium), 1.84 wide (widest part). Femur II length/diameter (l/d): 3.71. Legs, tarsal formula (leg I to IV): 1-5-4-5. Leg lengths; I: coxa 0.61/ trochanter 1 0.32/ trochanter 2 -/ femur 0.76/ patella 0.42/ tibia 0.60/ metatarsus 0.77/ tarsus 0.24/ total 3.72; II: 0.77/ 0.44/ -/ 1.24/ 0.65/ 1.01/ 1.11 / 1.25 / 6.47; III: 0.66/ 0.38/ 0.37/ 0.88/ 0.50/ 0.62/ 0.71/ 0.66/ 4.78; IV: 0.61/ 0.43/ 0.41/ 0.95/ 0.51/ 0.66/ 0.72/ 0.66/ 4.95. Leg length formula: 2-4-3-1.

Differs from male as follows: carapace paler reddish, median longitudinal depression shallower than on male. Femora II less robust than those on male. Tibiae II without ventral conical apophyses, but with some sharp-tipped granules, femora II slightly curved on prolateral-distal part. Metatarsus II with the scattered sharp-tipped granules smaller than those on male. Metatarsus II straight. Opisthosoma wider, higher and larger than in male, paler reddish ( Figs 27–28 ). Median tergites X–XIII wider than those on male ( Fig. 27 ). Spermathecae with two oval lobules on each side, one as long as the other, with widespread tiny pores throughout ( Figs 29‒31 ).

Natural history

The specimens were collected manually in oak forest litter.

Distribution

Mexico: Chiapas ( Fig. 36 ).

Figures

Figs 3–6. Pseudocellus giribeti sp. nov. Holotype, ♂ (MCZ 80010). 3–4. Habitus, dorsal and ventral views. 5. Carapace, dorsal view. 6. Prosoma, ventral view, showing coxosternal region. Scale bars: 3–4 = 2 mm; 5–6 = 0.5 mm.

Figs 7–10. Pseudocellus giribeti sp. nov. Holotype, ♂ (MCZ 80010). 7–8. Opisthosoma, dorsal and ventral views. 9. Tergite XI, median plate (arrow indicates the lateral depression). 10. Pygidium, posterior view. Scale bars: 7–8 = 1 mm; 9 = 0.5 mm; 10 = 0.2 mm.

Figs 11–19. Pseudocellus giribeti sp. nov. Holotype, ♂ (MCZ 80010). 11. Cucullus, dorsal view.12. Left chelicera, dorsal view. 13–14. Right tibia II, prolateral and proventral views. 15–16. Right metatarsus II, prolateral and proventral views. 17. Right femur II, prolateral view. 18. Detail of the movable and fixed claws of the right pedipalp, retrolateral view. 19. Right pedipalp tibia, retrolateral view. Scale bars: 11, 13–17, 19 = 0.5 mm; 12 = 0.2 mm; 18 = 0.1 mm.

Figs 20–26. Pseudocellus giribeti sp. nov. Holotype, ♂ (MCZ 80010). 20–22. Right leg III (copulatory apparatus), retrolateral, prolateral and dorsal views. 23. Copulatory apparatus extended, prolateral view. 24. Copulatory apparatus, dorsal view. 25. Copulatory apparatus, prolateral view. 26. Tarsal process, distal half, prodorsal view. Scale bars: 20–22 = 0.5 mm; 23–25 = 0.2 mm; 26 = 0.1 mm.

Figs 27–31. Pseudocellus giribeti sp. nov. Paratype, ♀ (MCZ 80010). 27–28. Habitus, dorsal and ventral views. 29–31. Spermathecae, anterior, posterior and lateral views, respectively. Scale bars: 27–28 = 2 mm; 29–31 = 0.2 mm.

Figs 32–35. Pseudocellus giribeti sp. nov. Paratypes (MCZ 80010). 32–33. Deutonymph, habitus, dorsal and ventral views. 34–35. Tritonymph, habitus, dorsal and ventral views. Scale bars = 2 mm.

Fig. 1. Neighbour-Joining (NJ) tree with p-distances constructed with COI barcode sequences from different specimens and species of Pseudocellus Platnick, 1980. Colors of the branches indicate species of Pseudocellus already described, red branches indicate the new species. Numbers on the branches represent Bootstrap support values (>50% significant).

Fig. 36. Species of the genus Pseudocellus Platnick, 1980 described from Chiapas, Mexico, including the new species described herein. Star: El Triunfo Biosphere Reserve, El Quetzal Camp, Angel Albino Corzo Municipality. Red circle: Cerro Boquerón, Ejido Boquerón, Motozintla Municipality. Orange circle: Sumidero del Camino, 16 km NE of Comitán. Pink circle: Kolem-chen Cave “Cueva Grande”, Chan-kin Reserve, Ocosingo Municipality. Blue circle: San Francisco Cave, La Trinitaria Municipality. Purple circle: Finca Guatimoc, south slope of the Tacaná volcano, 32 km north of Tapachula, near Cacahuatán. Green circle: Las Abejas Cave, San Fernando Municipality.