Oecobius culichi, Alcántar-Valenzuela & Chamé-Vázquez & Jiménez, 2025

Alcántar-Valenzuela, Joel Jair, Chamé-Vázquez, David & Jiménez, María-Luisa, 2025, Four new species of the spider genus Oecobius Lucas, 1846 (Araneae: Oecobiidae) from northwestern Mexico, Zootaxa 5679 (4), pp. 501-520 : 503-505

Oecobius culichi spec. nov.

Figs 1–10 , 61–63

Type material. Holotype: 1♂ (CARCIB-Ar-038): MEXICO: Sinaloa, Culiacán, Culiacán Rosales (24.7644°N, 107.3443°W, 108 m), tropical deciduous forest, manual collection, J. Alcántar leg., 11/VII/2022.

Paratypes: Same data as for holotype, 1♀ (CARCIB-Ar-039) ; same data as for holotype, 3♂ 3♀ 16 juvs (CARCIB-Ar-0229) ; same data as for holotype, 2♂ 2♀ (CARCIB-Ar-230) .

Etymology. The specific epithet refers to the Spanish popular term “culichi ”, which means “native of Culiacán”, in reference to the type locality.

Diagnosis. Male palp of O. culichi spec. nov. resemble those of O. hoffmannae by having the radical apophysis and protrusion forming a C-shape concavity in prolateral view ( Figs 5 , 61 ); however, O. culichi spec. nov. possesses the radical apophysis shorter than the terminal apophysis ( Figs 5 , 61 ; vs. about of the same length in O. hoffmannae , Figs 45 , 70 , Jiménez & Llinas 2005: fig. 2) and apically blunt ( Figs 6 , 62 ; vs. apically flattened in O. hoffmannae , Figs 46 , 72 , Jiménez & Llinas 2005: fig. 3). Females of O. culichi spec. nov. resemble those of O. piaxtla Shear, 1970 by having a relatively short and wide scape; however, the scape in O. culichi spec. nov. is oval-shaped and transverse ( Fig. 8 ; vs. narrowed distally in O. piaxtla, Shear 1970 : fig. 38), and the posterior portion of copulatory ducts are spiraled ( Figs 9, 10 ; vs. tubiform in O. piaxtla, Shear 1970 : fig. 38).

Description. Male. Coloration. Carapace light brown with three dark and three white submarginal spots, and two small white spots in the clypeal area. The eye area bordered with black. Legs whitish, with black rings on segments (usually broken) as follows: Fm with two, Pa with one, Ti with two, Mt with two, Ta with one, very diffused distally ( Fig. 1 ). Sternum, labium and endites whitish, sternum with short, diffused dark lines directed to the center ( Fig. 2 ). Opisthosoma dorsum whitish, with white and black spots interspersed, and a large, brown cardiac mark; sides suffused with dark spots ( Fig. 1 ). Opisthosoma venter dark brown anteriorly and posteriorly, median area whitish, with few interspersed dark and white spots and broken longitudinal brown stripes. Spinnerets and anal tubercle are mostly whitish, but distal segment of PLS darker dorsally ( Fig. 2 ).

Carapace suboval, wider than long, with subtriangular clypeal projection. AER and PER slightly recurved. PLE largest, separated by two diameters; PME subtriangular and opalescent, separated by one diameter. AME smallest, separated by one diameter; ALE opalescent, slightly smaller than PLE, closer to AME than PLE. Endites subtriangular. Opisthosoma suboval and slightly pointed posteriorly. Measurements: total length 1.94. Carapace 0.74 long, 0.84 wide. Opisthosoma 1.19 long, 0.76 wide. Ti I 0.50, II 0.51, III 0.53, IV 0.58.

Palp. In prolateral view, radical apophysis and protrusion delimits a C-shape concavity; radical apophysis subtriangular, with blunt apex; radical protrusion short, triangular, and pointed; terminal apophysis subtriangular (basally broad, distally pointed) ( Figs 5 , 61 ). Conductor with two sclerotized apophyses directed retroventrally, the subapical one long and spiniform, the subbasal one small and triangular; embolus base broad, apically tubiform, directed ventrally ( Fig. 7 ).

Female. Coloration: Similar to male, except for carapace darker and white spots inconspicuous; sternum with dark lines inconspicuous. Dorsum of opisthosoma suffused with more dark spots, but venter with less white spots. Measurements: total length 2.52. Carapace 0.79 long, 0.86 wide. Opisthosoma 1.73 long, 1.29 wide. Ti I 0.50, II 0.54, III 0.50, IV 0.58.

Epigyne. Scape wider than long, oval-shaped, restricted to the anterior half of epigynal plate; posterior half of epigynal plate striated; copulatory openings closely spaced, near the scape apex ( Fig. 8 ). Vulva . Copulatory ducts directed anteriorly then arched laterally toward receptacles, first part somewhat tubular, then spiraled; receptacles hyaline and globose; sclerotized capsules elongated, sinuous, situated laterally to copulatory openings; blind appendix reniform, restricted to posterior third of the epigynal length ( Figs 9–10 ).

Variation. Female carapace coloration is usually darker than that in male. The number of white and darks spots on opisthosoma venter varies, but males generally have a reduced number of black spots. Measurement: Females (N=3): total length 2.22–2.74. Carapace 0.73–0.82 long, 0.83–0.88 wide. Opisthosoma 1.49–1.92 long, 1.16–1.52 wide. Ti I 0.50–0.55, II 0.53–0.57, III 0.48–0.58, IV 0.56–0.66. Males (N=3): total length 1.89–1.94. Carapace 0.74–0.79 long, 0.84–0.86 wide. Opisthosoma 1.09–1.19 long, 0.76–0.89 wide. Ti I 0.49–0.50, II 0.51–0.56, III 0.53–0.55, IV 0.58–0.60.

Natural history. Specimens of this species were found beneath stones in disturbed areas of tropical deciduous forest near residential areas. In July 2022, we documented the presence of two rounded ovisacs, containing six and seven eggs, respectively (N=2).

Distribution. Known only from its type locality in Culiacán, Sinaloa ( Fig. 76 ).

Figures

FIGURE 76. Distribution of Oecobius species based on records from the current paper, Shear (1970), and Jiménez & Llinas (2005).

FIGURES 1–10. Oecobius culichi spec. nov. 1. male habitus, dorsal; 2. same, ventral; 3. female habitus, dorsal; 4. same, ventral; 5. male palp, prolateral; 6. same, ventral; 7. same, retrolateral; 8. epigyne, ventral; 9. cleared epigyne, ventral; 10. same, dorsal. Scale bars 1–4: 1.0 mm; 5–7: 0.30 mm; 8–10: 0.10 mm. Abbreviations: BA—blind appendix; C—conductor; CD—copulatory ducts; CO—copulatory openings; E—embolus; FD— fertilization ducts; K—sclerotized capsule; R—receptacle; RA—radical apophysis; TA—terminal apophysis.

FIGURES 61–69. 61–63. Oecobius culichi spec. nov. 64–66. O. sudcaliforniana spec. nov. 67–69. O. yoreme spec. nov. 61, 64, 67. male palp, prolateral. 62, 65, 68. same, ventral. 63, 66, 69. same, retrolateral. The processes of the conductor are colorcoded as follows: green for the subapical process, red for the median process, and blue for the subbasal process. Scale bars 61–69: 0.10 mm. Abbreviations: C—conductor; E—embolus; RA—radical apophysis; RP—radical protrusion; TA—terminal apophysis.

FIGURES 41–50. Oecobius hoffmannae. 41. male habitus, dorsal; 42. same, ventral; 43. female habitus, dorsal; 44. same, ventral; 45. male palp, prolateral; 46. same, ventral; 47. same, retrolateral; 48. epigyne, ventral; 49. cleared epigyne, ventral; 50. same, dorsal. Scale bars 41–44: 1.0 mm; 45–47: 0.30 mm; 48–50: 0.10 mm. Abbreviations: BA—blind appendix; C— conductor; CD—copulatory ducts; CO—copulatory openings; E—embolus; FD—fertilization ducts; K—sclerotized capsule; R—receptacle; RA—radical apophysis; TA—terminal apophysis.

FIGURES 70–75. 70–72. Oecobius hoffmannae. 73–75. O. isolatoides. 70, 73. male palp, prolateral. 71, 74. Same, ventral. 72, 75. Same, retrolateral. Scale bars 70–75: 0.10 mm. The processes of the conductor are color-coded as follows: green for the subapical process, red for the median process, and blue for the subbasal process. Abbreviations: C—conductor; E—embolus; RA—radical apophysis; RP—radical protrusion; TA—terminal apophysis.