Salvadora gymnorhachis Hernández, 2019

Hernández-Jiménez, Carlos A., Flores-Villela, Oscar, Aguilar-Bremauntz, Aranzazú & Campbell, Jonathan A., 2021, Phylogenetic relationships based on morphological data and taxonomy of the genus Salvadora Baird & Girard, 1853 (Reptilia, Colubridae), European Journal of Taxonomy 764 (1), pp. 85-118 : 105-111

Salvadora gymnorhachis Hernández , Flores & Campbell, 2019

Fig. 11

Diagnosis

Eight–9 supralabials, two supralabials, fourth and fifth in contact with the eye; 8–10 infralabials; preocular scale divided; a single loreal scale; prenasal in contact or separated from the second supralabial; a second pair of chinshields in contact or separated by a row of scales; 176–186 ventral scales; 92–103 subcaudal scales; tail is 18 to 21% of the total length; 11 +3 maxillary teeth. Color pattern consists of a pair of dark dorsolateral lines that begin behind the eyes and fade before reaching the middle of the body, without a well-defined vertebral line and lacking lateral lines.

This species differs clearly from the other species by lacking dorsolateral lines on about the posterior two-thirds of the body and by lacking vertebral and lateral lines across the body.

Etymology

The name is derived from the Greek prefixes ‘ gymnós ’, which means ‘naked’ and ‘ ráchḭ ’ which means ‘back’.

Type material examined

MEXICO • ♀; Oaxaca, Distrito Mixe, San Pedro and San Pedro Ayutla ; 17.00159° N, 96.08443° W; 24 Aug. 2014; MZFC 28775 .

Distribution and conservation

Mountains of central Oaxaca, Mexico ( Fig.11 ).

This is a recently described taxon and one of limited distribution that is not known to inhabit any protected natural areas. This species is not included in Mexican legislation and is not in the IUCN’s red list.

Dichotomous key for the species and subspecies of the genus Salvadora

1. A single preocular ( Fig. 12A ); more than 123 subcaudals; three supralabials in contact with the eye; maxillary teeth 14 + 3 to 15 +3; tail length more than 29% of total body length ( mexicana group). 2

– Preocular generally divided ( Fig. 12B ); fewer than 116 subcaudals; normally fewer than three supralabials in contact with the eye; maxillary teeth from 9+3 to 12 +3; tail length generally less than 29% of total body length ( grahamiae group)............................................................................ 3

2. Four longitudinal lines on the posterior part of the body that are interrupted in the first third of the body by transverse patches or crossbars ( Fig. 13A ); 182–197 ventral scales; tail length 31% to 42% of total length; maxillary teeth 15 + 3 .................... S. mexicana ( Duméril, Bibron & Duméril, 1854)

– Four well-defined longitudinal lines extending along the body without transverse patches or crossbars on the first third of body ( Fig. 13B ); 194 to 205 ventral scales; tail length between 29% and 33% of total length; maxillary teeth 14 +3 ........................................................... S. lemniscate ( Cope, 1895)

3. Supralabials normally eight (rarely 7 or 9), fourth and fifth in contact with the eye ( Fig. 14A ); a second pair of chinshields in contact with each other or separated by one row of scales ( Fig. 15A ........................................................................................................................................................... 4

– Nine or ten supralabials (rarely 11 or 12), generally the sixth is in contact with the eye ( Fig. 14B ); posterior pair of chinshields sometimes separated by two rows of scales ( Fig.15B )........................ 8

4. Maxillary teeth 11 +3; dorsolateral lines normally present along the body or incomplete present only in the first third of body, lateral line normally present on third or fourth row of dorsal scales, or absent when the dorsolateral line is incomplete (populations from Guerrero, Oaxaca or south of Puebla)............................................................................................................................................... 5

– Maxillary teeth 9 +3 or 10 +3; dorsolateral line always present; lateral line well defined on the third or fourth row of dorsal scales, or vestigial or absent......................................................................... 6

5. Dorsolateral lines present along the entire body; a light, yellowish vertebral line; lateral lines always present; tail length 23 to 30 % of total body length .............................. S. intermedia Hartweg, 1940

– Dorsolateral lines absent on the second and last third of the body; no lateral lines on body; tail length is 19 to 21 % of total length................................................................................................................. ......................................... S. gymnorhachis Hernández-Jiménez, Flores-Villela & Campbell, 2019

6. Maxillary teeth 9+ 3; vertebral line normally separated from the parietal region by a patch formed by the fusion of the dorsolateral lines ( Fig. 16A ); dorsolateral lines do not reach the temporal region; vertebral line three scale rows wide on the first and second third of the body (sometimes interrupted by dark blotches), and one row wide on the last third; lateral line well defined and separated from the dorsolateral line the entire length of the body ............................... S. bairdi Jan & Sordelli, 1860

– Maxillary teeth 10 + 3; vertebral line reaching the parietal region ( Fig. 16B ); dorsolateral lines pass through the temporal region to the eye; vertebral line from three to five rows wide on the first third of the body, and three rows wide on the second and last third of the body; lateral line present, vestigial or barely discernible, or may be absent in some specimens ............................................................. 7

7. Lateral line absent, vestigial, or scarcely discernible ( Fig. 17A ) ........................................................ .................................................................................................... S. grahamiae Baird & Girard, 1853

– Lateral line always present and well defined ( Fig. 17B ) .............................. S. lineata Schmidt, 1940

8. Loreal scale normally single ( Fig. 18A ); vertebral line five rows wide on the first third of body; lateral line well defined, largely restricted to adjoining margins of scales in third and fourth rows, clearly separated from the dorsolateral line on the second and last thirds of body; 68 to 86 subcaudals.............................................................................................. S. deserticola Schmidt, 1940

– Loreal normally divided ( Fig. 18B ); vertebral line generally 3 rows wide, sometimes more; lateral line ill-defined or well-defined but fused or feebly separated from the dorsolateral lines; 75 to 103 subcaudals.......................................................................................................................................... 9

9. Vertebral line yellowish in color, no more than three scale rows in width along the entire body; dorsolateral lines brown fused with the lateral lines in the anterior part of body but feebly separated posteriorly, generally without subocular scales, overall appearance brown........................................ ................................................................................................................. S. h. virgultea Bogert,1935

– Vertebral line light grey in color, more than three rows wide (3 to 7) on the first third of the body; dorsolateral lines brown or grey in color, and four rows wide on the first third of the body, three rows wide in the second and one row wide on the last third of the body, and regularly separated or slightly separated from the lateral lines, with or without subocular scales .................................................. 10

10. Normally two supralabials reaching the eye ( Fig. 19A ); 12 +3 maxillary teeth ................................ .................................................................................................................. S. h. klauberi Bogert,1945

– Fewer than two supralabial reaching the eye ( Fig. 19B ); 10 or 11 +3 maxillary teeth ....................11

11. Supralabials normally separated from the eye by the presence of two or more subocular scales ( Fig. 20A );10–11 infralabial scales; 11 +3 maxillary teeth; sometimes with an irregular pattern of bars running the length of the body that interrupt the dorsolateral and lateral lines ........................... .............................................................................................................. S. h. mojavensis Bogert,1945

– One supralabial in contact with the eye ( Fig. 20B ); normally without suboculars or when present there is only one; normally 10 infralabials; 10+3 maxillary teeth; vertebral line three scales in width; dorsolateral line nearly gray, often irregularly pigmented, and obscurely separated from lateral line anteriorly, over-all appearance gray....................................................... S. h. hexalepis ( Cope, 1866)

Figures

Fig. 11. Locality records of Salvadora gymnorhachis Hernández-Jiménez, Flores-Villela & Campbell, 2019.

Fig. 12. A. Single preocular. B. Preocular generally divided.

Fig. 13. A. Longitudinal lines interrupted in the first third of the body. B. Longitudinal lines extending along the body.

Fig. 14. A. Supralabials fourth and fifth in contact with the eye. B. Sixth supralabial in contact with the eye.

Fig. 15. A. Second pair of chinshields separated by one row of scales. B. Second pair of chinshields separated by two rows of scales.

Fig. 16. A. Vertebral line normally separated from the parietal region. B. Vertebral line reaching the parietal region.

Fig. 17. A. Lateral line absent. B. Lateral line always present and well defined.

Fig. 18. A. Loreal scale single. B. Loreal normally divided.

Fig. 19. A. Two supralabials reaching the eye. B. Fewer than two supralabials reaching the eye.

Fig. 20. A. Two or more subocular scales. B. One supralabial in contact with the eye.