A new genus of Theraphosid spider from Mexico, with a particular palpal bulb structure (Araneae, Theraphosidae, Theraphosinae) Author Jorge I. Mendoza Author Arturo Locht Author Radan Kaderka Author Francisco medina Author Fernando Pérez-Miles text European Journal of Taxonomy 2016 2016-09-23 232 1 28 journal article 32196 10.5852/ejt.2016.232 8253f751-e408-4e55-b851-13d612f48a79 885395 52029B02-4A79-442D-8DA2-8DF3099ED8D0 Magnacarina cancer Mendoza & Locht sp. nov . urn:lsid:zoobank.org:act:8B262491-E2F2-43F2-BA8A-A81EBE09D842 Figs 5–7 , 16 Diagnosis Magnacarina cancer sp. nov. differs from all other Magnacarina species in the general shape of the male palpal bulb, with a prolateral inferior keel pointing to primary projection - resembling a crab claw. Secondary projection lacking prolateral accessory keels. Also M. cancer sp. nov. differs from other species in possessing a more developed accessory apophysis. Females differ in having a very reduced spermatheca. Magnacarina cancer sp. nov. possesses the following character combination: male palpal bulb with a short primary projection, with distal half twisted to apical ( Fig. 6 A–C); retrolateral keel slightly developed; prolateral superior keel wide and well developed, posterior extension ends at the middle of prolateral face ( Fig. 6 D–E). Secondary projection short, lacking prolateral accessory keels ( Fig. 6 D). Prolateral inferior keel short and broader distally, apex acute and directed to Ppr - resembling a crab claw ( Fig. 6 A–B, E). Apical keel wide and covering the sperm pore ( Fig. 6 E). Accessory apophysis pointed dome shape and well developed ( Fig. 5 H). The retrolateral apophysis is thicker on distal half. The retrolateral nodule of megaspines very short and wide ( Fig. 5 F, I–J). Spermatheca very reduced, only a small rounded receptacle, as long as wide. Uterus externus is five times wider, and three times longer than the spermatheca ( Fig. 7 D). Etymology The specific epithet is in reference to the Latin word cancer (crab), describing the shape and orientation of the primary projection and apical keel that resembles a crab claw. Type material Holotype MEXICO : ♂ , Jalisco , Tomatlán, Estación de Biología Chamela , 7 Mar. 1990 , coll. S. Guzmán ( CNAN-T0991 ) . Paratypes MEXICO : 1 ♀ , Jalisco , Tomatlán, Estación de Biología Chamela , 10 Jan. 1990 , coll. S. Guzmán ( CNAN-T0992 ) ; 1 ♂ , same locality, 6 Feb. 1990 , coll. S. Guzmán ( CNAN-T0993 ) ; 1 ♂ , same locality, 19 Feb. 1990 , coll. S. Guzmán ( CNAN-T0994 ) ; 1 ♂ , same locality, 4 Mar. 1987 , coll. S.H. Bullock ( LAAH ) . Description Holotype male CNAN-T0991 ( Figs 5–6 ) Body length (not including chelicerae and spinnerets) 10.15, carapace: 5.33 long, 4.0 wide. Caput not markedly elevated; fovea procurved, 0.95 wide. Carapace without dark cephalic area ( Fig. 5 A). Eyes: anterior eye row procurved, posterior eye row recurved. Eyes sizes and interocular distances: AME 0.26; ALE 0.36; PME 0.16; PLE 0.32; AME–AME 0.10; AME–ALE 0.04; PME–PME 0.42; PME–PLE 0.03; ALE–PLE 0.04. Ocular tubercle, width 1.16; length 0.88; clypeus lacking ( Fig. 5 D). Labium: length 0.90; width 1.20; with 26 cuspules. Maxilla inner corner with approximately 66-68 (left-right). Cheliceral promargin with 11-11 teeth (left-right). Sternum length 2.80. Sigilla oval, first to third hardly visible; posterior sigilla one and half times its length from the margin ( Fig. 5 B). Leg formula: IV> I> II> III. Length of legs and palpal segments (femur, patella, tibia, metatarsus, tarsus, total): I: 5.72, 3.54, 4.49, Fig. 5. Magnacarina cancer Mendoza & Locht sp. nov., ♂, holotype (CNAN-T0991). A . Carapace, dorsal view. B . Prosoma, ventral view. C . Opisthosoma, dorsal view. D . Ocular tubercle, dorsal view. E–J . Left side. E . Palp tibia, dorsal view. F . Metatarsus I, retrolateral view. G . Tibial apophyses, ventral view. H . Tibial apophyses, retrolateral view. I . Retrolateral nodule with megaspines, ventral view. J . Retrolateral nodule with megaspines, retrolateral view. Scale bars: A–C = 2 mm; E–H = 1 mm; D, I–J = 0.5 mm. 3.53, 3.05, 20.33; II: 4.76, 2.96, 3.61, 3.64, 2.96, 17.93; III: 4.32, 2.26, 3.49, 4.18, 2.90, 17.15; IV: 6.11, 2.42, 4.93, 5.59, 3.39, 22.44. Palp: 3.61, 2.25, 3.27, -, 1.62, 10.75. Spinnerets: PMS, 0.77 long, 0.30 apart; PLS, 1.10 basal, 0.70 middle, 1.06 distal. Tarsi I–IV scopulate, I to III divided by narrow band of setae, IV divided by strong band of setae. Metatarsi I scopulate on distal third; II scopulate on distal third, III slightly scopulate on distal third, and IV slightly scopulate on distal fourth. Tibia I with three apophyses. Prolateral apophysis conical with smaller internal spine. Retrolateral apophysis wide through its length, thick and slightly curved to dorsal position at apex ( Fig. 5 G–H). Accesory apophyses pointed dome shape and well developed, bearing three megaspines at the apex ( Fig. 5 H). Metatarsus I curved ( Fig. 5 F), with retrolateral megaspines nodule well developed, having 12 very short and wide spines ( Fig. 5 I–J). Retrolateral face of palpal tibiae with a prominent conical process in the middle, covered by short setae ( Fig. 5 E). Chaetotaxy (left side): femora I 1 p; II 1 p; III 1 r; IV 1 r; palp 1p; patellae none; tibiae I 2 p, 4v ; II 2 p, 6v ; III 2 p, 5v , 2r; IV 5v , 2r; palp none; metatarsi: I 1v ; II 2 p, 6v ; III 4 p, 6v , 2r; IV 2 p, 7v , 2r. Palpal bulb with short and wide primary projection, strongly curved retrolaterally and its distal half twisted to apical. Retrolateral keel thin and slightly developed. Prolateral superior keel wide and well developed, posterior extension ends in the middle of prolateral face ( Fig. 6 A–D). Secondary projection short lacking, prolateral accessory keels (Fig. D). Prolateral inferior keel short and broader distally, apex acute and directed to primary projection ( Fig. 6 D–E), shape similar to the crab claw ( Fig. 6 A–B). Apical keel wide covering the sperm pore, which opens towards prolateral face ( Fig. 6 E). Lacking tegular apophysis. Urticating setae type III arranged in one oval dorsomedian patch, with copper metallic iridescence, intermixed with long yellowish setae ( Fig. 5 C). Variations summarized in Table 1 . Fig. 6. Magnacarina cancer Mendoza & Locht sp. nov., ♂, holotype (CNAN-T0991), left palpal bulb. A . Retrolateral view. B . Prolateral view. C . Dorsal view. D . Apex, prolateral view. E . Apex, apical view. White arrow indicates sperm pore. Scale bars: A–C = 1 mm; D–E = 0.5 mm. Color pattern: damaged by preservation in ethanol, carapace tegument looks yellowish; ventral coxae, labium, maxillae and sternum brown; abdomen dorsally brown with whitish setae, ventrally brown. Legs and palps yellowish. Paratype female CNAN-T0992 ( Fig. 7 A–D) Body length (not including chelicerae and spinnerets) 13.70, carapace: 5.20 long, 4.50 wide. Caput not markedly elevated; fovea recurved, 0.70 wide. Carapace without dark cephalic area ( Fig. 7 A). Eyes: anterior eye row procurved, posterior eye row recurved. Eyes sizes and interocular distances: AME: 0.23; ALE: 0.28; PME: 0.12; PLE: 0.22; AME–AME: 0.10; AME–ALE: 0.05; PME–PME: 0.38; PME–PLE: 0.02; ALE–PLE: 0.06. Ocular tubercle, width 0.98; length 3.50; clypeus 0.06 ( Fig. 7 C). Labium: length 1.10; width 1.11; with 60 cuspules. Maxilla inner corner with approximately 97-100 (left-right). Cheliceral promargin with 8-8 (left-right) teeth. Sternum length 2.45. Sigilla oval, first to third pairs hardly visible; posterior sigilla once its length from the margin ( Fig. 7 B). Leg formula: IV> I> II> III. Length of legs and palpal segments (femur, patella, tibia, metatarsus, tarsus, total): I: 3.79, 2.54, 2.92, 2.11, 1.69, 13.05; II: 3.47, 2.32, 2.54, 2.01, 2.05, 12.39; III: 2.92, 1.69, 2.17, 2.12, 1.62, 10.52; IV: 4.10, 2.07, 3.20, 3.36, 2.23, 14.96. Palp: 3.19, 1.84, 2.09, -, 1.94, 9.06. Spinnerets: PMS, 0.825 long, 0.30 apart; PLS, 1.375 basal, 0.95 middle, 1.15 distal. Tarsi I–IV scopulate, I to III divided by narrow band of setae, IV divided by strong band of setae. Metatarsi I scopulate on distal half; II scopulate on distal half, III scopulate on distal third, and IV scopulate on distal fourth. Chaetotaxy (left side): femora I 1 p; II 1 p; palp 1p; patellae none; tibiae III 1 p, 3v , 1r; IV 2v , 1r; metatarsi I 2v ; II 2v ; III 4 p, 5v , 2r; IV 2 p, 7v , 3r. Spermatheca very reduced, only a rounded receptacle as long as wide. Strongly sclerotized with the top oriented ventrally. Uterus externus is five times wider and three times longer than the spermatheca ( Fig. 7 D). Urticating setae of type III arranged in one dorsomedian patch, with copper metallic iridescence. Variations summarized in Table 1 . Fig. 7. Magnacarina cancer Mendoza & Locht sp. nov., ♀, paratype (CNAN-T0992). A . Carapace dorsal view. B . Prosoma, ventral view. C . Ocular tubercle, dorsal view. D . Spermatheca, ventral view. Scale bars: A–B = 2 mm; D = 1 mm; C = 0.5 mm. Color pattern: damaged by preservation in ethanol, carapace tegument looks yellowish; ventral coxae, labium, maxillae and sternum brown; abdomen dorsally brown with whitish setae, ventrally brown. Legs and palps: yellowish. Distribution The species is known only from the type locality in the Natural Protected Area of Chamela in Jalisco ( Fig. 16 ). Specimens were collected in scrapes under medium size rocks and the males wandering during daytime. Nothing is known about its life cycle or natural history. We know, however, that the same area is inhabited by Brachypelma klaasi (Schmidt & Krause, 1994) , Bonnetina cyaneifemur Vol, 2000 , and Aphonopelma sp., so it is possible there exists competition or even predation of M. cancer sp. nov. by these larger species.