Myrmecicultor pueblaensis Cushing and González-Santillán, 2025

Myrmecicultor pueblaensis Cushing and González-Santillán , sp. nov.

Figures 2B, 2D, 2F View FIGURE 2 , 3B View FIGURE 3 , 4B, 4D, 4F View FIGURE 4 , 5D, 5E, 5F, 5H View FIGURE 5 , 6 View FIGURE 6

Type series. Male holotype ( UNAM CNAN-Ar011706); female allotype and additional paratypes ( DMNS ZA.46195). All specimens collected in Mexico, Puebla, 10 Km west of Zapotitlán Salinas , N 18.33510°, W 97.51850°, 1587 m elev.; 9 July 2024; collected by authors while headlamping at night from 20:00 – 23:30 hrs. This desert habitat is within the Poblano-Oaxaca Semiarid Region ( Abd El-Ghani et al. 2017) GoogleMaps .

Etymology. The specific epithet is an adjective referring to the state of Puebla, Mexico. This is, thus far, the only locality from which these spiders have been collected.

Diagnosis. The two species of Myrmecicultor differ in the following morphological characters ( Table 2, Figs. 2–5 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 ): PME lens convex in M. chihuahuensis and flattened in M. pueblaensis sp. nov.; cheliceral basal transverse ridge is absent in M. chihuahuensis and present in M. pueblaensis sp. nov.; cheliceral promargin teeth are present in M. chihuahuensis and absent in M. pueblaensis sp. nov.; pronounced mound on the cheliceral retromargin is absent in M. chihuahensis and present in M. pueblaensis sp. nov.; the endites are not obliquely depressed in M. chihuahuensis but are so in M. pueblaensis sp. nov. and the endites are only slightly longer than wide in M. chihuahuensis (more or less triangular in shape) whereas the endites of M. pueblaensis sp. nov. are distinctly longer than wide (compare Figs. 2 E and F View FIGURE 2 ); ventral distal macrosetae on the endites are absent in M. chihuahuensis whereas M. pueblaensis sp. nov. has a scattering of ventral distal macrosetae; the anterior margin of the sternum is straight in M. chihuahuensis and convex in M. pueblaensis sp. nov. (compare Figs. 2E and F View FIGURE 2 ); precoxal triangles on the female are absent in M. chihuahuensis and present (fused to the sternum) in M. pueblaensis sp. nov. ( Figs. 2 E and F View FIGURE 2 ). In addition, M. chihuahuensis has a broader and more medially positioned RTA in M. chihuahuensis whereas the RTA is more more elongate and more apically positioned in M. pueblaensis sp. nov. ( Figs. 5G, H View FIGURE 5 ). The dorsal color pattern of the two species are also distinctive: M. chihuahuensis has a pale yellow carapace and pale abdomen lacking patterns; M. pueblaensis sp. nov. has a dark brownish-orange carapace and the abdomen is dark grey with three distinct white markings ( Figs. 2 View FIGURE 2 A-D). The fangs of M. chihuahuensis are long and thin whereas M. pueblaensis sp. nov. has much shorter fangs.

Description. Ecribellate entelegyne spider with two tarsal claws, lacking claw tufts; males with RTA ( Fig. 5H View FIGURE 5 ); with six spinnerets in a tight group ( Fig. 6B View FIGURE 6 ); female palpal claw well developed with several teeth in a row; AME and PME recurved ( Figs. 2B, 2D View FIGURE 2 , 3 B View FIGURE 3 ); PME oblong, oval with well-developed obliquely oriented tapeta ( Figs. 2B, D View FIGURE 2 ); serrula on anterior border of endites (arrow Fig. 6A View FIGURE 6 ); endites elongate and medially depressed; dorsal apical patch of setae on cymbium of males ( Fig. 5H View FIGURE 5 ) and palp of females ( Fig. 6C View FIGURE 6 ); and distinct, precoxal triangles fused to sternum ( Fig. 2F View FIGURE 2 ). Chelicerae with one retromarginal tooth and denticle with large diastema between; promargin with no teeth; lightly sclerotized area beside three large bristle-setae on promargin ( Fig. 6A View FIGURE 6 ); short fangs with serrated edge; serrula on edge of endites ( Fig. 6A View FIGURE 6 , white arrow); anterior part of fangs translucent with venom duct evident ( Fig. 6A View FIGURE 6 ). Genitalia as illustrated in Figs. 4 View FIGURE 4 and 5 View FIGURE 5 .

Male holotype ( UNAM CNAN-Ar011706): All measurements in mm. Total length 2.47. Carapace broadly oval in dorsal view, highest in front of fovea. Carapace length 1.06; width 1.00. Clypeus high, almost twice ALE diameter. Clypeus height at AME 0.19; at ALE 0.17. Fovea a narrow, dark longitudinal line. Carapace highest in cephalic region. Sternum shield-shaped with pointed extension between coxae IV. Precoxal triangles faint but present. Marginal setae on sternum. Labium length 0.12; width 0.23. Endite length 0.4; width 0.19. Serrula on anterior margin of endites. Eyes: AME diameter 0.10, ALE diameter 0.10, PME diameter 0.09, PME length 0.11, PLE diameter 0.09. Eye inter-distances: AME-AME 0.07, AME-PME 0.05, AME-ALE 0.02, PME-PME 0.03, PME-PLE 0.08, ALE-PLE 0.04. AER 0.41. PER 0.48. Eyes ringed with black pigment; tapeta present in PME, PLE, and ALE. Leg I total 4.81 (femur 1.35, patella 0.40, tibia 1.16, metatarsus 1.19, tarsus 0.71). Leg II total 4.22 (femur 1.18, patella 0.38, tibia 1.00, metatarsus 1.04, tarsus 0.62). Leg III total 4.19 (femur 1.24, patella 0.38, tibia 0.87, metatarsus 1.10, tarsus 0.60). Leg IV total 5.65 (femur 1.62, patella 0.40, tibia 1.35, metatarsus 1.50, tarsus 0.78). Leg formula IV, I, II, III. Color: dorsal abdomen with two anterior large white dots and posterior white mark consisting partly of white flattened setae surrounded by dark greyish-black background ( Fig. 2D View FIGURE 2 ). Additional flat white setae scattered on dorsum; ventral abdomen white; legs orange with femora slightly darker; carapace orange with scattered white setae, particularly on cephalon. All legs with single spine on proximal-dorsal surface of femora; no ventral spines. All legs with flattened, translucent setae on dorsum of femora. Metatarsi III & IV with preening brush ( Fig. 6D View FIGURE 6 ). Thick, comb-like setae on all tarsi. Single trichobothria on distal dorsal metatarsi; several trichobothria on tarsi. Trochanter IV 1.3 times trochanter III. Palp as in Figs. 5D, E, F, H View FIGURE 5 . Cymbium with dorsoapical patch of sensory setae ( Fig. 5H View FIGURE 5 ). Conductor bifurcate at tip( Fig. 5D View FIGURE 5 and embolus tube distinctly visible at tip ( Fig. 5F View FIGURE 5 ).

Female allotype ( DMNS ZA.46195; largest female in lot, separated from other paratypes) : Total length 3.68. Carapace length 1.5; width 1.29. Clypeus at AME 0.30; at ALE 0.21. Fovea a narrow, dark longitudinal line. Carapace highest in cephalic region. Sternum shield-shaped with pointed extension between coxae IV. Precoxal triangles distinct ( Fig. 2F View FIGURE 2 ). Marginal setae on sternum. Labium length 0.18; width 0.28. Endite length 0.55; width 0.19. Serrula on anterior margin of endites. Eyes: AME diameter 0.13, ALE diameter 0.12, PME diameter 0.10, PME length 0.13, PLE diameter 0.09. Eye inter-distances: AME-AME 0.10, AME-PME 0.09, AME-ALE 0.03, PME-PME 0.06, PME-PLE 0.12, ALE-PLE 0.05. AER 0.50. PER 0.60. Tapeta present in PME, PLE, and ALE. Leg I total 5.87 (femur 1.59, patella 0.51, tibia 1.32, metatarsus 1.55, tarsus 0.90). Leg II total 5.26 (femur 1.46, patella 0.51, tibia 1.10, metatarsus 1.44, tarsus 0.75). Leg III total 5.09 (femur 1.37, patella 0.51, tibia 1.03, metatarsus 1.51, tarsus 0.67). Leg IV total 6.74 (femur 1.92, patella 0.52, tibia 1.60, metatarsus 1.88, tarsus 0.82). Leg formula IV,I, II, III. Color: dorsal abdomen with two anterior large white dots and posterior white mark consisting partly of white flattened setae surrounded by dark greyish-black background ( Fig. 2B View FIGURE 2 ). Additional flat white setae scattered on dorsum; ventral abdomen white; legs orange with femora slightly darker; carapace orange with scattered white setae, particularly on cephalon. All legs with single spine on proximal-dorsal surface of femora; no ventral spines. All legs with flattened, translucent setae on dorsum of femora. Metatarsi III & IV with preening brush, although brush on IV is reduced. Thick, comb-like setae on all tarsi. Single trichobothria on distal dorsal metatarsi; several trichobothria on tarsi. Trochanter IV 1.94 times trochanter III. Female ventral and dorsal epigynal structures as in Figs. 4B, D, F View FIGURE 4 : two small copulatory openings lead internally to copulatory tubes. Spermathecae widely separated ( Figs. 4D, F View FIGURE 4 ) .

Male paratype ( DMNS ZA.46195; male placed in vial with female paratypes described below): Color, markings, setal characters, body shape, leg formula as for the holotype except leg femora not noticeably darker and pre-coxal triangles present but faint. Measurements as follows. Total length 2.56. Carapace length 1.17; width 0.98. Clypeus at AME 0.24; at ALE 0.16. Labium length 0.14; width 0.23. Endite length 0.39; width 0.15. Eyes: AME diameter 0.09, ALE diameter 0.09, PME diameter 0.10, PME length 0.11, PLE diameter 0.09. Eye inter-distances: AME-AME 0.09, AME-PME 0.04, AME-ALE 0.03, PME-PME 0.04, PME-PLE 0.10, ALE-PLE 0.02. AER 0.41. PER 0.48. Leg I total 4.93 (femur 1.40, patella 0.40, tibia 1.17, metatarsus 1.25, tarsus 0.71). Leg II total 4.19 (femur 1.12, patella 0.38, tibia 0.94, metatarsus 1.11, tarsus 0.64). Leg III 4.14 (femur 1.11, patella 0.39, tibia 0.83, metatarsus 1.19, tarsus 0.62). Leg IV total 5.47 (femur 1.56, patella 0.41, tibia 1.30, metatarsus 1.50, tarsus 0.70) .

Female paratypes ( DMNS ZA.46195, 4 females placed in with male paratype): Color, markings, setal characters, body shape, leg formula as for allotype except one female has both marginal setae on sternum as well as scattered setae on center area of sternum. Measurements as follows. Total lengths: 3.75, 3.20, 2.97, 2.87 (all females, x̅ including allotype = 3.29). Carapace lengths: 1.34, 1.32, 1.32, 1.39 (all females, x̅ = 1.37). Carapace widths: 1.22, 1.16, 1.10, 1.20 (all females, x̅ = 1.19). Clypeus at AME: 0.32, 0.25, 0.25, 0.27 (all females, x̅ = 0.28). Clypeus at ALE: 0.24, 0.17, 0.17, 0.20 (all females, x̅ = 0.20). Labium lengths: 0.17, 0.17, 0.13, 0.17 (all females, x̅ = 0.16). Labium widths: 0.29, 0.26, 0.32, 0.28 (all females, x̅ = 0.29). Endite lengths: 0.44, 0.44, 0.49, 0.41 (all females, x̅ = 0.47). Endite widths: 0.20, 0.19, 0.21, 0.20 (all females, x̅ = 0.20). AME diameters: 0.13, 0.10, 0.10, 0.10 (all females, x̅ = 0.11). ALE diameters: 0.10, 0.10, 0.11, 0.11 (all females, x̅ = 0.11). PME diameters: 0.10, 0.10, 0.11, 0.08 (all females, x̅ = 0.10). PME lengths: 0.15, 0.12, 0.13, 0.13 (all females, x̅ = 0.13). PLE diameters: 0.11, 0.08, 0.10, 0.10 (all females, x̅ = 0.10). AME-AME: 0.10, 0.08, 0.10, 0.10 (all females, x̅ = 0.10). AME-PME: 0.07, 0.07, 0.09, 0.07 (all females, x̅ = 0.08). AME-ALE: 0.04, 0.04, 0.03, 0.03 (all females, x̅ = 0.03). PME-PME: 0.03, 0.03, 0.03, 0.05 (all females, x̅ = 0.04). PME-PLE: 0.13, 0.12, 0.13, 0.11 (all females, x̅ = 0.12). ALE-PLE: 0.06, 0.05, 0.04, 0.05 (all females, x̅ = 0.05). AER: 0.59, 0.47, 0.48, 0.49 (all females, x̅ = 0.51). PER: 0.59, 0.53, 0.52, 0.54 (all females, x̅ = 0.56). Leg I totals: 5.51, 5.18, 4.98, 5.39 (all females, x̅ = 5.39). Leg II totals: 4.86, 4.55, 4.55, 4.72 (all females, x̅ = 4.79). Leg III totals: 4.77, 4.50, 4.40, 4.56 (all females, x̅ = 4.66). Leg IV totals: 6.19, 5.75, 5.86, 6.03 (all females, x̅ = 6.11) .

Natural History: Spiders observed hunting in large groups made up of adult males, females, and juveniles in open areas of desert habitat. Ants seen in the vicinity with the spiders. Ants not collected or identified. One spider observed approaching ant from behind, biting rear leg, then retreating. This hunting behavior is essentially identical to the myrmecophagous behavior observed for M. chihuahuensis ( Cushing et al. 2022) . We suspect that the genus Myrmecicultor may be found throughout the desert habitats of southern Mexico and that additional species may be found in association with various species of ants as has been documented for M. chihuahuensis ( Ramírez et al. 2019; Cushing et al. 2024).