Crotalus ehecatl, Carbajal-Márquez & Cedeño-Vázquez & Martínez-Arce & Neri-Castro & Machkour- M’Rabet, 2020

Carbajal-Márquez, Rubén Alonso, Cedeño-Vázquez, José Rogelio, Martínez-Arce, Arely, Neri-Castro, Edgar & Machkour- M’Rabet, Salima C., 2020, Accessing cryptic diversity in Neotropical rattlesnakes (Serpentes: Viperidae: Crotalus) with the description of two new species, Zootaxa 4729 (4), pp. 451-481 : 465-468

Crotalus ehecatl sp. nov.

Figs. 7–8 , Table 3

Crotalus culminatus — Heimes (2016): 439 (in part);

Crotalus simus— Savage et al. (2005): 370; Wüster et al. (2005): 1097 ( Fig.1 ), 1103; Heimes (2016): 470 (in part), 492 (Fig. 619), 518 (Map 186).

Crotalus simus simus — Campbell & Lamar (2004): 584 (Fig. 212; Map 109), 586, Plate 956.

Crotalus durissus durissus — Klauber (1941): 61, 64, 65, 67, 71; Smith & Taylor (1950): 348; Armstrong & Murphy (1979): 10; McCranie (1993): 577.2 (Map 1), 577.5.

Holotype. Adult male ( ECO-CH-H-3778 ) collected on 22 October of 2016 by Jorge Arturo Hidalgo García , in San José Tintonishac (16.29366°, 91.961840°; 1504 m asl), Las Margaritas, state of Chiapas, Mexico.

Paratypes. Six specimens, all from Mexico. Chiapas: Juvenile female ( ECO-CH-H-3777 ) collected 08 October of 2016 by J.A. Hidalgo García , in San José Tintonishac (16.2941°, -91.95931 °; 1497 m asl), municipality of Las Margaritas ; juvenile female ( ECO-CH-H-3776 ) collected on 24 September of 2015 by T. Ramírez Valverde and R.A. Carbajal Márquez, at 12.2 km west of Chiapa de Corzo (16.706618°, -92.896292 °; 1071 m asl), municipality of Chiapa de Corzo. Oaxaca: adult female (SDSNH-24383) and adult male ( MCZ-R-27819 ) collected on 1929 by W. W. Brown Jr., at San Pedro Tepanatepec (16.368660 °, - 94.193445°; 63 m asl), municipality of San Pedro Tepanatepec; collected on July 1927 by W.W. Brown Jr., at San Pedro Tepanatepec (16.368660°, - 94.193445°; 63 m asl), municipality of San Pedro Tepanatepec. Adult female ( MCZ-R-27821 ) collected July 1927 by Wilmot W. Brown Jr., at San Pedro Tepanatepec (16.368660°, - 94.193445°; 63 m asl), municipality of San Pedro Tepanatepec . Adult male ( MCZ-R-46485 ) collected on January 1942 by W. Barker near Santo Domingo Tehuantepec (16.324765°, -95.238529°; 52 m asl), municipality of Santo Domingo Tehuantepec .

Diagnosis. A rattlesnake belonging to the Crotalus durissus species complex, characterized as other species by a prominent vertebral process and conspicuous scale tuberculations. The distribution range of C. ehecatl closely approaches to those of C. culminatus and C. simus , and to a lesser extent to C. mictlantecuhtli . Crotalus ehecatl can be distinguished from all members of the Crotalus durissus species complex by exclusive combination of the following characters: paravertebral stripes of two scale rows, usually paravertebral stripes with light center on the nape, length of paravertebral stripes of 22 scales, 31 dorsal body blotches, intercanthal scales in 18.7% (n =16) of specimens, interpreocular scale in 50% (n =16) of specimens, first infralabial scale divided in 18.7% (n =16), postrostral scale in 12.5% (n =16), usually 1 postsupraloreal scale, contact between lacunal and supralabial scales in 56.2% (n =16) of specimens, postocular stripe of three scales, usually with light center, contact between paravertebral stripes and supraocular scales in 68.7% (n =16) of specimens, and a dark prefrontal bar interrupted in 93.7% (n =16) of specimens.

Comparisons. Crotalus ehecatl is most closely related to species of the northern clade ( C. culminatus ) of the Crotalus durissus species complex, and is distinguished from these species by having 168–186 (mode=181) ventral scales in males, 177–187 (mode=187) in females; number of subcaudal scales 27–32 (mode=31) in males, 21–26 (mode=24) in females (vs. 25–32 [28] males, 20–25 [22] females in C. culminatus , and 27–32 [28] males, 20–26 [23] females in C. mictlantecuhtli ); mid-dorsal scale rows 27–31 (mode=27) (vs. 27–33 [29] in C. culminatus ); width of paravertebral stripe of two scales, usually with light center in the nape (vs. three commonly with light center in C. mictlantecuhtli , and usually one in C. culminatus ); intercanthal scales present in 18.7% (vs. absent in C. mictlantecuhtli , and 60% in C. culminatus ); first infralabial scales divided in 18.7% (vs. no divided in C. mictlantecuhtli , and 56% in C. culminatus ); postrostral scale present in 12.5% (vs. absent in C. mictlantecuhtli , and 44% in C. culminatus ); prenasal-supralabial scales contact in 93.7% (vs. present in 100% in C. mictlantecuhtli , and 80% in C. culminatus ); interpreocular scale present in 50% (vs. absent in C. mictlantecuhtli , and 20% in C. culminatus ); usually three anterior intersupraocular scales (vs. usually two in C. mictlantecuhtli ); presupraloreal sometimes present (vs. absent in C. mictlantecuhtli ); one or two postloreal scales sometimes present (vs. absent in C. mictlantecuhtli ); usually one postsupraloreal scale (vs. usually absent in C. mictlantecuhtli , and two in C. culminatus ); superciliar scale absent (vs. present in 20.8% in C. culminatus ); lacunal-supralabial scales contact in 56.2% (vs. 68% in C. mictlantecuhtli and 16.6% in C. culminatus ); post-ocular stripe of three scales in width and usually with a light center (vs. 3.0–3.5 scales width and usually light center in C. mictlantecuhtli , and three scales width and faded coloration in C. culminatus ); usually 31 (25–31) dorsal body blotches in males (vs. usually 24 [23–27] in C. mictlantecuhtli , and 26 [22–30] in C. culminatus ); in females 30 (25–30) (vs. usually 23 [22–26] in C. mictlantecuhtli , and 27 [26–31] in C. culminatus ); contact between paravertebral stripes and supraoculars in 68.7% (vs. 97% in C. mictlantecuhtli , and 24% in C. culminatus ); and the prefrontal bar interrupted in 93.7% (vs. 100% in C. mictlantecuhtli , and 96% in C. culminatus ). Crotalus ehecatl is distinguished from C. simus by higher number of ventral scales 168–186 (181) vs. 170–177 (170), less number of scales length of paravertebral stripe 9–33 (22) vs. 20–39 (27), intercanthal scales present in 18.7% (vs. presence of 10%), first infralabial scale divided in 18.7% (vs. not divided), postrostral scale present in 12.5% (vs. absent), contact between prenasal and first supralabial scale of 93.7% (vs. contact of 100%), interpreocular scale present in 50% (vs. absent), usually three (2–5) anterior intersupraoculars (vs. usally two [2–4]), superciliar scale absent (vs. rarely present), contac between lacunal and supralabial sales of 56.2% (vs. not contact), postocular stripe of three scales with light center (vs. three scales and faded), tertiary blotches not conspicuous (vs. conspicuous), paravertebral stripes often with light center only in the nape (vs. without light center), contact of paravertebral stripes with supraoculars of 68.7% (vs. contact of 80%), prefrontal bar interrupted in 93.7% (vs. interrupted in 90%).

Description of the holotype. SVL 1204 mm, TL 105 mm, head length 51 mm, head width 32.6 mm; middorsal scale rows 27, mid-tail scale rows 10, rattle fringe scales 10; ventrals 168, subcaudals 27; supralabials 14–15, infralabials 13–16; rostral slightly higher than wide; internasals two equally wider than long; canthal one on either side; intercanthals three, with seven scales in the internasal-prefrontal area; anterior intersupraoculars five + six; suture between intersupraoculars and canthals not evident; supraoculars the largest scales of the head scales; pre- and postnasals approximately equal in size; nostril mostly contained in the postnasal; prenasals contact first supralabials; prefoveals seven; lacunals contact the third supralabials; infraloreal, supraloreal and postsupraloreal present on both sides; upper preocular larger; lower preocular contacts loreal; interpreocular absent; five scales below center of the eye, between the orbit and the edge of the lip; mental triangular; first infralabial of the left side divided; genials long, intergenials and submentals absent.

Crotalus ehecatl is not brightly patterned, usually having less contrast between the dark brown-black blotches and yellow-brown interspaces. Head yellow cream above, dark brown internasals and prefrontal bar interrupted encompassing the canthals and anterior edges of intersupraoculars and supraoculars; dark brown, near black paravertebral stripes do not reach the posterior edge of supraoculars, with three to five scale width in the nape, and light center; diagonal dark brown postocular bars of three scales wide, not conspicuous as the paravertebrals, with light center; sides of the head yellow cream, with a brown spot beneath and posterior of the loreal pit; underside of the head immaculate cream. Pattern of the body consist of a pair of dark brown, near black paravertebral stripes 16 scales length, two scales wide, separated by a dark yellow buff stripe of three scales wide, somewhat lighter than the lateral scales; first row of scales below each paravertebral buff, lighter than the lateral scales; 29 black dorsal dia- monds, sharper posteriorly and somewhat truncated anteriorly, each one bordered by a cream white scale and light brown center, a secondary blotch associated in each side, below the lateral angle of the primary, comprised of four to five scales and same color, tertiary blotches between secondary blotches not conspicuous; lateral areas between diamonds punctated with light brown; toward the tail, the pattern becomes obscure; tail dark gray above and buff below, with crossbands slightly evident.

Color in life. Color in life varies with adult specimens presenting low contrast between blotches and interspaces, although some are more contrasting ( Fig. 8 ).

Variation. Largest male 1653 mm in total length (UTA-R 51456; see Campbell & Lamar 2004), and female 1180 mm SVL, 85 mm TL (MCZ-R 27821); ventrals 168–186 (mode=181; n= 6) in males, 177–187 (mode=187; n= 8) in females; subcaudals 27–32 (mean=31; n= 6) in males, 21–26 (mean=24; n= 9) in females; midbody scale rows 27–31 (mode=27; n =15); width of paravertebral stripe 1–3 (mode=2; n= 15); length of the paravertebral stripe 9–33 (mode=22; n= 15); one supraloreal, one infraloreal and one postsupraloreal in all examined specimens; contact between lacunal and supralabial scales (n= 9), or no contact (n= 6); dorsal body blotches 25–31 (mode=31; n =6) in males, 25–30 (mode=30; n= 9) in females; contact between paravertebral stripes and posterior edge of supraoculars (n= 11), or no contact (n= 5). We refer to Table 3 for variation in additional quantitative and qualitative features.

Etymology. The specific epithet “ ehecatl ”, derives from the Nahuatl word “ Ehēcatl ” and means “The wind” or “Lord of the wind”. In Mexican mythology (Aztec), Ehécatl is the god of the wind. It is usually interpreted as one of the manifestations of Quetzalcóatl, the feathered serpent, taking the name of Ehécatl-Quetzalcóatl, appearing in the breath of living beings and in the breezes that bring the clouds with rain for the sowings. His breath starts the movement of the Sun, and brings life to what is inert. Also, he clears the way for Tláloc . The species name is used as an invariable noun in apposition to the generic name. We suggested the vernacular name: Tehuantepec Isthmus Neotropical rattlesnake.

Habitat and distribution. Crotalus ehecatl inhabits mostly open dry areas with rocky outcrops in tropical deciduous forest and seasonal rain forest along the Pacific versant of Mexico from central-south Oaxaca, southward across the Tehuantepec Isthmus to west of Tonalá, Chiapas, almost reaching the Central Valleys in Oaxaca, and in the Grijalva River basin reaching Comitán, Chiapas, from 0–1585 m asl. This species is known from the state of Oaxaca, and Chiapas, and may range to southeastern Veracruz, and eastern Huehuetenango, Guatemala ( Fig. 4 ).

Figures

FIGURE 1. (A) Maximum-likelihood phylogram of the four genes (cyt b, ND4, ND2, c-mos, 2596 bp) analysis (-ln L=- 17,270.83). Tip labels are as follows: 3-letter subspecies code for the Crotalus durissus species complex, following Campbell & Lamar (2004), locality and haplotypes in parentheses, see Appendix 1. Numbers along branches indicate bootstrap support-ML and Bayesian posterior probability. For clarity, support is only shown for important nodes. (B) Maximum-likelihood phylogram of the four genes (cyt b, ND4, ND2, c-mos, 2596 bp) analysis (-ln L=-17,270.83). Tip labels are as follows: 3-letter subspecies code for the Crotalus molossus species complex and outgroups, following Campbell & Lamar (2004) and Anderson & Greenbaum (2012), locality and haplotypes in parentheses, see Appendix 1. Numbers along branches indicate bootstrap support-ML and Bayesian posterior probability. For clarity, support is only shown for important nodes.

FIGURE 4. Geographic distribution of species in the Crotalus durissus species complex distributed across Mexico and Central America. Circled dots indicate type localities. The circles indicate specimens where sequence and morphology were obtained; squares only morphology; triangles only sequences. Names of species reflect our proposed taxonomy.

FIGURE 7. Dorsal and lateral view of the head of the holotype of Crotalus ehecatl (ECO-CH-H 3778).

FIGURE 8. Crotalus ehecatl in life, (A) ECO-CH-H 3778, holotype from San José Tintonishac, Las Margaritas, Chiapas; (B) adult specimen from Tuxtla Gutiérrez, Chiapas; (C) UTA-R 51456, adult male from Santa Inés, Santa María Chimalapa, Oaxaca; (D) neonate specimen from Santa María Mixtequilla, Oaxaca; (E) neonate specimen from San Pedro Tapanatepec, Oaxaca; (F) adult specimen from San Pedro Totolápam, Oaxaca. Photos by J.A. Hidalgo García (A), E.B. Jiménez Díaz (B), E.N. Smith courtesy of J.A. Campbell (C), I.T. Ahumada Carrillo (D), HERP.MX (E), and F. Martínez Belmar (F).