Hemirrhagus akheronteus, Mendoza & Francke, 2018

Mendoza, Jorge I. & Francke, Oscar F., 2018, Five new cave-dwelling species of Hemirrhagus Simon 1903 (Araneae, Theraphosidae, Theraphosinae), with notes on the generic distribution and novel morphological features, Zootaxa 4407 (4), pp. 451-482 : 455-460

Hemirrhagus akheronteus sp. nov.

( Figs 2 ̄5)

Type material: holotype ♂ CNAN T0807, MEXICO: Querétaro, Mpio. Jalpan de Serra , Las Animas , Cueva del Río Jalpan, 06-V-2012, Coll . CEMAC Querétaro. Paratype ♀ CNAN T0808, MEXICO: Querétaro, Mpio. Jalpan de Serra , Las Animas , Cueva del Río Jalpan, 03-V-2013, Coll. J. Mendoza, J. Cruz, G. Contreras, R. Monjaraz.

Diagnosis. Hemirrhagus akheronteus sp. nov. can be distinguished from all other Hemirrhagus species by the lack of posterior median eyes in both sexes, and by the presence of posterior spinose setae in the opisthosoma dorsoposterior on male.

Hemirrhagus akheronteus sp. nov. is identified by possessing the following character combination: male palpal bulb with slender embolus, as long as tegulum, subapical keel retrolaterally extended ends at embolus retrolateral face; the posterior curvature of subapical keel occurs at the base of embolus; ventral groove deep; embolus strongly curved retrolaterally on distal half. The apex of the embolus slightly curved ventrally ( Fig 3A ̄D). Ocular tubercle undeveloped; anterior median eyes reduced, anterior lateral eyes normally developed, posterior median eyes absent, posterior lateral eyes reduced. Periocular pigmentation absent ( Fig 2D , 4D ). Lacking urticating setae on abdomen ( Fig 2C , 4E ). The male posseses a group of 11 spinose setae on opisthosoma dorsoposterior (PSP), these setae are in a socket and are mobile; also look similar to those seen on the legs ( Fig 2H ). Spermatheca paired, slightly fused at the base, receptacles finger-shape, longer than wide at the base and strongly bent laterally ( Fig 4G ).

Etymology: The specific name is from latin akheronteus , which means pertaining to the stream of woe, referring to the acheron river in the infernal regions of Greek mythology.

Description: Holotype male CNAN T0807 body length, 21.60, carapace 8.93 long, 8.89 wide. Caput not markedly elevated; fovea recurved, width 1.63 ( Fig 2A ).

Eyes: anterior eye row straight, posterior eye row straight. Periocular pigmentation absent, AME reduced, ALE normally developed, PME absent, PLE reduced. Eye sizes and interocular distances: AME 0.175; ALE 0.275; PME -; PLE 0.125; AME-AME 0.20; AME-ALE 0.10; PME-PME -; PME-PLE -; ALE-PLE 0.01. Ocular tubercle undeveloped, ocular quadrangle width 1.20, length 0.45; clypeus absent ( Fig 2D ). Labium length 1.325, width 1.525; with 15 cuspules. Maxilla inner corner with ~127 (left) and ~106 (right) cuspules ( Fig 2E ). Cheliceral promargin with 12 (left) and 14 (right) teeth (proximal to distal: first small, second-fourth large, fifth medium, sixth small, seventh medium, eighth-eleventh large, twelfth medium; first small, second-sixth large, seventh small, eighth large, ninth small, teenth-thirteenth large, fourteenth medium). Sternum length 4.0. Sigillae oval, first, second and third pairs hardly visible; posterior sigilla once its length from the margin ( Fig 2B ).

Leg formula: IV, I, III, II. Length of legs and palpal segments (femur, patella, tibia, metatarsus, tarsus, total): I: 10.34, 5.30, 9.72, 9.44, 6.91, 41.71. II: 9.99, 5.03, 9.09, 8.94, 6.42, 39.47. III: 9.79, 4.11, 9.42, 9.84, 6.89, 40.05. IV: 11.98, 4.29, 10.93, 15.04, 7.90, 50.14. Palp: 7.28, 3.68, 6.37, -, 2.54, 19.87. Spinnerets: PMS, 0.96 long, 0.50 apart; PLS, 1.67 basal, 1.17 middle, 2.03 distal; midwidths: 0.77 basal, 0.70 middle, 0.47 distal.

Scopulae: Tarsi I-IV entirely scopulated, II-III divided by narrow band of setae and IV divided by strong band of setae. Metatarsi I-II densely scopulated; III 65 % scopulated distally, IV 25 % scopulated distally.

Tibia I with two apophyses, which do not originate from a common base, prolateral apophysis reduced and located between two large spinose setae, which exceed the apex of prolateral apophysis; retrolateral apophysis normally developed, with one large spinose seta on dorsal face, the spinose seta exceeds the apex of retrolateral apophysis ( Fig 2F ̄G). Metatarsus I straight ( Fig 2I ).

Stridulatory setae: with plumose setae on palp coxa retrolateral face, trochanter retrolateral face, femur prolateral and retrolateral faces; leg I coxa prolateral and retrolateral faces, trochanter prolateral and retrolateral faces, femur prolateral face; leg II coxa prolateral face, trochanter prolateral face, femur prolateral face.

Chaetotaxy (left side): femora I 3 p, 2r; II 2 p, 2r; III 3 p, 1r; IV 3 p, 2r; palp 1p; patellae none; tibiae I 2 p, 6v, 3r; II 2 p, 8v, 1r; III 3 p, 10v, 3r; IV 2 p, 9v, 3r; palp 2p, 6v; metatarsi I 1 p, 2v; II 1 p, 2v; III 4 p, 12v, 2r; IV 5 p, 14v, 3r.

Palp. Embolus slender, one and half times the length of tegulum, subapical keel ends at embolus retrolateral face; ventral groove deep. Embolus strongly curved retrolaterally on distal half. The apex of the embolus slightly curved ventrally ( Fig 3A ̄D).

Urticating setae: lacking, but posseses a group of 11 spinose setae on opisthosoma dorsoposterior (PSP), these setae are inserted in a socket and are mobile ( Fig 2C,H ). This spinose setae looks at first sight similar to those seen on the legs..

Color pattern: in ethanol specimen color is pale brown. Live specimen is dark brown.

Paratype female CNAN T0808: body length 24.63, carapace 10.29 long, 8.18 wide. Caput not markedly elevated; fovea straight, 2.13 wide ( Fig 4A ).

Eyes: anterior eye row straight, posterior eye row straight. Periocular pigmentation absent, AME reduced, ALE normally developed, PME absent, PLE reduced. Eye sizes and interocular distances: AME 0.15; ALE 0.30; PME -; PLE 0.225; AME-AME 0.19; AME-ALE 0.125; PME-PME -; PME-PLE -; ALE-PLE 0.01. Ocular tubercle undeveloped, ocular quadrangle width 1.43, length 0.40; clypeus absent ( Fig 4D ). Labium length 1.63, width 1.95; with 18 cuspules. Maxilla inner corner with ~153 (left) and ~152 (right) cuspules ( Fig 4F ). Cheliceral promargin with 15 (left) and 15 (right) teeth (proximal to distal: first small, second medium, third-sixth large, seventh medium, eighth large, ninth medium, tenth-fifteenth large; first-second small, third-seventh large, eigth small, ninth large, tenth small, eleventh-fifteenth large). Sternum length 4.25. Sigillae oval, second, third and fourth pairs hardly visible; fourth pair once its length from the margin ( Fig 4B ).

Leg formula: IV, I, II, III. Length of legs and palpal segments (femur, patella, tibia, metatarsus, tarsus, total): I: 10.30, 5.44, 9.39, 8.83, 6.56, 40.52. II: 9.77, 5.13, 8.84, 7.94, 6.41, 38.09. III: 9.57, 4.47, 8.21, 9.81, 5.71, 37.77. IV: 11.85, 4.68, 10.99, 14.04, 7.98, 49.54. Palp: 7.42, 4.24, 6.43, -, 5.97, 24.06. Spinnerets: PMS, 1.27 long, 0.90 apart; PLS, 2.07 basal, 1.40 middle, 2.43 distal; midwidths, 1.0 basal, 0.97 middle, 0.67 distal.

Scopulae: Tarsi I–IV entirely scopulated, II–III divided by narrow band of setae and IV divided by strong band of setae. Metatarsi I–II densely scopulate; III 65 % escopulated distally, IV 25 % scopulated distally.

Stridulatory setae: with plumose setae on palp coxa retrolateral face, trochanter retrolateral face, femur prolateral and retrolateral faces; leg I coxa prolateral and retrolateral faces, trochanter prolateral and retrolateral faces, femur prolateral face; leg II coxa prolateral face, trochanter prolateral face, femur prolateral face.

Chaetotaxy (left side): femora I 1 p; II 1 p; III 2 p, 2r; IV 2 p, 2r; palp 1p; patellae palp 1v; tibiae I 2 p, 4v; II 2 p, 5v; III 2 p, 10v, 2r; IV 2 p, 8v, 3r; palp 1p, 11v; metatarsi I 2 v; II 2 v; III 3 p, 8v, 2r; IV 3 p, 10v, 3r.

Genitalia: spermatheca paired, slightly fused at the base, receptacles finger-shape, longer than wide at the base and strongly bent laterally ( Fig 4G ).

Urticating setae: Lacking. Unlike the male, does not have spinose setae on opisthosoma dorsoposterior ( Fig 4C, E ).

Color pattern: in ethanol specimen color is pale brown. Live specimen is dark brown ( Fig 5C ).

Distribution and natural history: Known only from Cueva del Río Jalpan, Querétaro, México ( Fig 23 ). This area is a subregion of the Sierra Madre Oriental. The species lives only inside the cave; specimens were collected on walls at a depth of 400 m from the entrance ( Fig 5A ̄B).

Figures

FIGURE 2. A─I, Hemirrhagus akheronteus new species, male holotype CNAN T0807.A, carapace, dorsal view.B, prosoma, ventral view showing the retrolateral projection on coxae of all legs (arrows show this feature only on coxa of third and fourth leg). C, opisthosoma, dorsal view indicating the positionof the posterior spinose setae.D, ocular tubercle, dorsal view.E, labial and maxillary cuspules. F, tibial apophyses, prolateral view. G, tibial apophyses, ventral view. H, opisthosoma, posterior view showing the posterior spinose setae. I, metatarsus I, prolateral view.Scale = 2mm (A̅C, H, I), 1mm (E), 0.8mm (F, G), 0.5mm (D).

FIGURE 3. A─D, Hemirrhagus akheronteus new species, male holotype CNAN-T0807. Left palpal bulb: A, dorsal view. B, ventral view. C, retrolateral view. D, prolateral view.Scale = 1mm.

FIGURE 4. A─G, Hemirrhagus akheronteus new species, female paratype CNAN-T0808. A, carapace, dorsal view. B, prosoma ventral view showing the retrolateral projection on coxae of all legs (arrows show this feature only on coxa of third and fourth leg). C, opisthosoma, dorsal view. D, ocular tubercle, dorsal view. E, opisthosoma, posterior view showing the absence of posterior spinose setae. F, labial and maxillary cuspules. G, Spermatheca, ventral view. Scale = 4mm (A̅C), 1mm (D̅F), 0.5mm (G).

FIGURE 5. A─C, Hemirrhagus akheronteus new species habitat and habitus; A, Entrance of Cueva del Río Jalpan. B, Inside of Cueva del Río Jalpan collecting site of the species. C, H. akheronteus sp. nov., female paratype CNAN-T0808, in life. Photos:A̅C, J. Mendoza.

FIGURE23. Known distribution of Hemirrhagusmitchelli(Gertsch 1982), Hemirrhagus puebla (Gertsch1982), Hemirrhagus ocellatus Pérez-Miles & Locht 2003, Hemirrhagus gertschi Pérez-Miles & Locht 2003, Hemirrhagus valdezi Mendoza 2014, Hemirrhagus akheronteus new species, Hemirrhagus diablo new species, Hemirrhagus billsteelei new species, Hemirrhagus pernix (Ausserer 1875), Hemirrhagus franckei Mendoza 2014, Hemirrhagus reddelli (Gertsch 1973), Hemirrhagus benzaa Mendoza 2014 and Hemirrhagus guichi Mendoza 2014. Showing the biogeographic provinces where they are found: SMO= Sierra Madre Oriental, EVT= Eje Volcanico Transversal, SMS= Sierra Madre del Sur, PCH= Provincia de Chiapas.