Crotalus ravus COPE, 1865
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Crotalus ravus
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| Higher Taxa | Viperidae, Crotalinae, Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes) |
| Subspecies | Crotalus ravus brunneus HARRIS & SIMMONS 1978 Crotalus ravus exiguus CAMPBELL & ARMSTRONG 1979 Crotalus ravus ravus COPE 1865 |
| Common Names | Mexican Pygmy Rattlesnake (brunneus: Oaxacan Pygmy Rattlesnake; exiguus: Guerreran Pygmy Rattlesnake; ravus: Central Plateau Pygmy Rattlesnake) S: Cascabel Enana |
| Synonym | Crotalus ravus COPE 1865: 191 Sistrurus ravus — BOULENGER 1896 Sistrurus ravus — DAVIS & SMITH 1953 Crotalus ravus lutescens HARRIS & SIMMONS 1978 (see comment) Sistrurus ravus — LINER 1994 Sistrurus ravus — MCDIARMID, CAMPBELL & TOURÉ 1999: 327 Crotalus ravus — MURPHY et al. 2002 Crotalus ravus — VALENCIA-HERNÁNDEZ et al. 2007 Piersonus ravus — HOSER 2009 Crotalus ravus — WALLACH et al. 2014: 193 Crotalus ravus brunneus HARRIS & SIMMONS 1978 Crotalus ravus brunneus — BRYSON 2007 Crotalus brunneus — GARCIA-PADILLA et al. 2020 Crotalus ravus exiguus CAMPBELL & ARMSTRONG 1979 Crotalus ravus exiguus — BRYSON 2007 Crotalus exiguus — OLIVEIRA-DALLAND et al. 2022 |
| Distribution | Mexico (WC Puebla, Veracruz, Morelos, Tlaxcala, C Guerrero, C Oaxaca, S Hidalgo) ravus: Mexico (central plateau); Type locality: tableland of Mexico. Subsequently restricted to Totalco, Veracruz, by Smith and Taylor, 1950. brunneus: Mexico (Oaxaca: Mesa del Sur); Type locality: 2.7 km E Ixtlan de Juárez. exiguus: Mexico (Guerrero: Sierra Madre del Sur); Type locality: 1.6 km E Omilteme, Guerrero, elevation 2090 m. |
| Reproduction | ovovivparous |
| Types | Syntypes: USNM 25050, USNM 25051, coll. C. Sartorius Holotype: UTA R-4533, an adult male; paratypes: UTA, KU [exiguus] Holotype: AMNH 102916 [brunneus] |
| Diagnosis | Diagnosis (ravus): A subspecies of S. ravus (Figs. 1, 2) distinguished from other races (Table 1) by normally having the dorsal scales in 21 rows at midbody, total prefoveals usually fewer than 3, a large rattle (dorsoventral width of proximal rattle segment usually exceeding 10% of tail length in males, 13% in females), and 2-4 tail bands in both sexes (from CAMPBELL & ARMSTRONG 1979). Diagnosis (exiguus): A subspecies of S. ravus distinguished from the other races (Table 1) by having the parietal scales divided trans- versely, the dorsal scales in 23 rows at mid- body, total prefoveals usually numbering six or more, a small rattle (PRW usually less than 10% of tail length in males, 13% in females), 3 to 6 tail bands in males, and 2 to 4 tail bands in females [from CAMPBELL & ARMSTRONG 1979]. Diagnosis (brunneus): A subspecies of S. ravus (Fig. 8) distinguished from the other races (Table 1) by having the parietals usually undi- vided, dorsal scales usually in 23 rows at midbody, total prefoveals usually exceeding 3 but not more than 6, a small rattle (PRW usually less than 109 of tail length in males, 13% in females), 5-8 tail bands in males, and 4-6 in females. The brief description of the holotype by Harris and Simmons (1978) contains two errors. There are 144 ventrals (not 148) and the total length is approxi- mately 660 mm (not 640 mm) [from CAMPBELL & ARMSTRONG 1979]. |
| Comment | Venomous! Subspecies: Another subspecies, S. r. sinaloensis has been proposed but “the description is woefully incomplete and the locality data are likely suspect” (CAMPBELL & LAMAR 1989: 376). Sistrurus ravus lutescens (HARRIS & SIMMONS 1978) is not listed in WELCH 1994 and not recognized as subspecies by GOLAY et al. (1993). Type Species: Crotalus ravus COPE 1865 is the type species of the genus Piersonus HOSER 2009 and is diagnosed as follows: “Large plates on the crown including the centre. 21 mid-body rows. Relatively short tail as compared to the snakes in the genus Sistrurus. For Piersonus gen. nov. males have an average tail length of 9.8 per cent of the total body length and females 7.7 per cent of the total body length. In Sistrurus the lateral hook of the squamosal makes an acute angle (45 to 80 degrees) with the main part of the bone. In Piersonus gen. nov., the lateral process of the squamosal is substantially at right angles to the main part of the bone. In Sistrurus, the upper preocular is in contact with the postnasal, the rostral is not curved over the snout, cathus rostralis is sharply angled, dorsal body blotches are square or wider than long. By contrast in Piersonus gen. nov. the upper preocular is not in contact with the postnasal, the rostral is curved over the snout, canthus rostralis is rounded, the dorsal body blotches are longer than wide or the colour is black.” (from HOSER 2009). Nomenclature: Hoser’s 2009 classification and nomenclature has been rejected as unnecessary and unavailable by WÜSTER & BERNILS 2011. |
| Etymology | C. r. exiguus was named from the Latin exiguus, meaning small, in reference to the size of the rattle. |
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