Modisimus sanpedro, Jimenez, Maria-Luisa & Palacios-Cardiel, Carlos, 2015

Jimenez, Maria-Luisa & Palacios-Cardiel, Carlos, 2015, A new species of Modisimus Simon (Araneae: Pholcidae) in Baja California Sur, Mexico, Zootaxa 4028 (4), pp. 595-599 : 595-598

Modisimus sanpedro new species

Figures 1–13

Diagnosis. Males of M. sanpedro n. sp. resemble those of M. caldera Huber, 1997 , by the general shape of the procursus, but M. sanpedro n. sp. presents a small dorsal spine contiguous with the procursus ( Figs. 3, 7 ) while M. caldera has it longer and separated (Huber 1997: figs. 38, 39). M. sanpedro n. sp. also resembles M. dominical Huber, 1997 , by having a thin and elongated bulbal apophysis tip, but M. sanpedro n. sp. has it slightly curved ventrally ( Fig. 6 ), while in M. dominical is straight (Huber 1997: figs. 53, 54). Females of M. sanpedro n. sp. can be distinguished by having two patches of three thick setae at the lateral borders of the epigynum, which run parallel to the epigastric furrow ( Figs. 10, 12 ).

Type material. Holotype: male (CARCIB 0014) from Mexico, Baja California Sur, San Pedro Oasis, Municipality La Paz (23°23′22.4″N, 110°12′30.2″W, 6 m. a.s.l.). 4.III.2013, C. Palacios and M. L. Jiménez Colls; Paratypes: 4 males (CARCIB 0087–0090), 10 females (CARCIB 0091-100), same data as holotype.

Etymology. The specific name is a noun in apposition which refers to the type locality.

Description. Male (Holotype, CARCIB 0014): Coloration. Carapace pale yellow, with scarce lateral setae. Thoracic region with three dark patches on each side and with a long and deep thoracic groove. Ocular area strongly elevated with a longitudinal and symmetric dark band, which extends forward from the middle part of clypeus, attenuating at the edge ( Fig. 1 ). Ocular area with six eyes and a tuft of black, curved setae between the eyes. Chelicerae pale yellow with an antero-ectal projection in front view and two patches of modified setae: one medial opposite to the antero-ectal projection and one basal next to the cheliceral fang. ( Fig. 2 ). Labium and endites light yellow with a dark line on distal edges. Sternum dark with one median light band and lateral clearer spots. Legs light yellow and long with numerous uniformly scattered setae; femora with rows of vertical small hairs and semicircular dark marks on ventral side and with tibiae and metatarsus slightly darker grey with a distal ring and curved and long setae. Tarsi pseudosegments: I, 17; II, 12; III, 9; IV, 12. Opisthosoma globose, longer than wide, with scarce greenish-grey setae and a colorless dorsal band that expands backward and aligned with two bands of white and black spots, one of them toward the sides. Distal part of opisthosoma is narrower, with a dark spot on each side, venter greenish grey with a black stain posterior to the epigastric furrow; dark grey spinnerets. Measurements: Total length 2.40; carapace length 0.92, width 0.99; clypeus high 0.66. Sternum wider than long (0.66/0.49). Eyes diameter: PME-PME 0.12, PME 0.08, PME-ALE 0.04 AME-AME 0.12, AME 0.06. Leg lengths: I—femur 6.87/patella 0.5/tibia 6.75/metatarsus 11.50/tarsus 1.3/total 22.38; II—5.0/ 0.5/ 3.75/ 7.30/ 1.30/ 17.85; III—3.62/ 0.5/ 3.1/ 5.0/ 1.3/ 13.52; IV—3.75/ 0.5/ 3.1/ 5.0/ 1.3/ 13.65. Leg formula: 1-2-4-3. Pedipalp: Procursus with a dorsal small spine in retrolateral view ( Figs. 3, 7 ). With a thin and elongated bulbal apophysis tip slightly curved ventrally in retrolateral view ( Figs. 6 ) but wide in dorsal view ( Fig. 5 ). Bulb oval in prolateral view ( Fig. 4 ). Femur apophysis hook-shaped and bent dorsally in retrolateral view, coxa with a small hump apophysis with short setae ( Fig. 3 ).

Female (Paratype, CARCIB 015). Coloration: Similar to male, but darker ( Figs. 8 – 9 ). Ocular area with several scattered setae (not forming a tuft). Chelicerae light yellow, but darker at the base. Labium and endites dark yellow. Legs ochre yellow, marks as in male. Tarsi pseudosegments: I, 14; II, 15; III, 5; IV, 11. Palps light yellow, metatarsus dark lighter proximally and tarsus dark. Opisthosoma with a light yellow dorsal band, two bands with white and dark grey spots and a dark grey posterior spot ( Figs. 8 – 9 ). Anterior spinnerets short and dark grey. Measurements: Total length 2.80, carapace length 0.69, wide 1.15; clypeus length 0.69. Sternum long as wider (0.66/0.66). Eyes diameter: PME- PME 0.12, PME 0.08, PME-ALE 0.06, AME-AME 0.14, AME 0.06. Leg lengths: I- 5.50/ 0.45/ 6.5/ 9.60/ 1.15/ 23.20; II-4.5/ 0.45/ 3.45/ 5.75/ 0.85/ 15.0; III-3.10/ 0.40/ 2.65/ 3.95/ 0.95/ 11.05; IV-3.75/ 0.35/ 3.15/ 4.95/ 0.75/ 12.95. Leg formula: 1-2-4-3. External female genitalia: Wider than long, with translucent sclerotized pattern and a small extension on each side with three long thick and erected setae in ventral view ( Figs. 10 – 12 ), and with a pair of anterior oval pore plates in dorsal view ( Figs. 11 – 13 ).

Variation. Males and females specimens present similar coloration as the types. However, some males (CARCIB 0087-0088) present three brown spots on each side of the prosoma. Chelicerae with variable number of short modified setae in two parches: one medial opposite to the antero-ectal projection and one basal next to the cheliceral fang. Total body length in males (n = 4): 1.60–1.80, carapace length 0.70–0.80, wide 0.80–0.85, clypeus high 0.45–0.50. Leg length: I—4.75–6.25/ 0.45–0.5/ 4.5–6.15/ 7.85–10.75/ 1.05–1.1/ 18.65–24.75; II—3.1–4.6/ 0.30–0.45/ 2.8–4.2/ 4.45–6.25/ 0.6– 0.9/ 11.25–16.4; III—2.55–3.2/ 0.3–0.35/ 2.1–2.75/ 3.25–4.25/ 0.6–0.65/ 8.8–11.3; IV—2.75–4.0/ 0.3–0.35/ 2.5–3.3/ 3.65–5.0/ 0.65–0.75/ 9.85–13.4. Total body length in females (n = 10): 1.80–2.35, carapace length 0.70–0.85, wide 0.70– 0.90, clypeus high 0.40–0.45. Legs length: I-4.25–5.80/ 0.35–0.45/ 4.0–5.20/ 6.75–8.75/ 1.05–1.20/ 16.4–21.40; II-2.55– 3.80/ 0.3–0.4/ 2.2–3.25/ 3.1–5.2/ 0.6–0.8/ 8.75–13.45; III-2.1–2.9/ 0.30–0.35/ 1.8–2.3/ 2.6–3.65/ 0.6–0.65/ 7.4–9.85; IV- 2.75–3.50/ 0.30–0.4/ 2.3–2.7/ 3.5–4.25/ 0.70–0.70/ 9.55–11.55.

Natural history. The oasis is a pond fed by a spring and separated from the sea by a broad beach and sand dunes. Further inland is a grove of Washingtonian palms Washingtonia robusta H. Wendl and date palms Phoenix dactylifera L. Specimens were collected in a place with high plant density and very wet soil in a flood zone. The spiders live close to the ground were webs can be found under folded young leaves or between leaves and dry trunks of W. robusta .

Remarks. This is the first record of Modisimus in this part of the North American desert.

Distribution. Known only for the type locality.

Figures

FIGURES 1 – 7. Modisimus sanpedro n. sp. (Male holotype, CARCIB 0014). 1. Ocular area, anterior. 2. Chelicerae, antero-ventral (arrow to antero-ectal projection). 3 – 7. Left pedipalp (3 retrolateral, 4 prolateral, 5 dorsal). 6. Bulbal apophysis and procursus distal detail, retrolateral). 7 Procursus dorsal spine, detail. Abbreviations: PC (procursus), BA (bulbal apophysis), CA (coxal apophysis), FA (femur apophysis).

FIGURES 8 – 13. Modisimus sanpedro n. sp. (Female paratype, CARCIB 015). 8 – 9. Habitus (8 dorsal, 9 ventral). 10 – 12. Epigynum, ventral, 11 – 13. Vulva, dorsal. Abbreviation: PP (pore plates).