Rena dulcis BAIRD & GIRARD, 1853
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|Higher Taxa||Leptotyphlopidae, Epictinae, Epictini, Typhlopoidea, Serpentes, Squamata (snakes)|
|Common Names||E: Texas Blind Snake|
dulcis: Plains Threadsnake
rubellum: South Texas Threadsnake
S: Culebrilla Ciega Texana
E: Tampico Threadsnake [myopica]
S: Culebrilla Ciega de Tampico [myopica]
E: New Mexico Blind Snake [dissecta]
G: New Mexico-Schlankblindschlange [dissecta]
S: Culebrilla Ciega de Nuevo Mexico [dissecta]
|Synonym||Rena dulcis BAIRD & GIRARD 1853: 142|
Stenostoma dulce — COPE 1861: 305
Stenostoma (Rena) dulce — JAN 1863: 15
Stenostoma tenuiculum GARMAN 1884: 5 (fide WALLACH et al. 2014)
Stenostoma rubellum GARMAN 1884
Stenostoma myopicum GARMAN 1884: 6
Stenostoma myopicum GARMAN 1884: 130
Stenostoma myopicum — GARMAN 1887: 129
Stenostoma tenuiculum — GARMAN 1887: 129
Stenostoma rubellum — GARMAN 1887: 129
Rena tenuicula — COPE 1887: 91
Leptotyphlops dulcis — STEJNEGER 1891: 501
Glauconia dulcis — COPE 1892: 590
Glauconia dulcis — BOULENGER 1893: 65
Glauconia myopica — BOULENGER 1893: 69
Glauconia dissecta COPE 1896: 753
Leptotyphlops myopica — BARBOUR & LOVERIDGE 1929
Leptotyphlops dulcis myopicus — KLAUBER 1940
Leptotyphlops dulcis dulcis — KLAUBER 1940: 108
Leptotyphlops humilis tenuiculus — KLAUBER 1940: 538
Leptotyphlops dulcis dissectus — KLAUBER 1940
Leptotyphlops myopicus myopicus — SMITH 1944: 146
Leptotyphlops myopicus myopicus — SMITH & TAYLOR 1945
Leptotyphlops myopicus dissectus — SMITH & TAYLOR 1945
Leptotyphlops myopicus dissectus — SMITH & SANDERS 1952: 216
Leptotyphlops dulcis dissectus — HAHN 1979
Leptotyphlops dulcis myopicus — HAHN 1979
Leptotyphlops dulcis dulcis — HAHN 1979
Leptotyphlops dulcis — STEBBINS 1985: 172
Leptotyphlops dulcis supraocularis TANNER 1985: 625 (fide HEIMES 2016)
Leptotyphlops dulcis — CONANT & COLLINS 1991: 144
Leptotyphlops dulcis — LINER 1994
Leptotyphlops dulcis — MCDIARMID, CAMPBELL & TOURÉ 1999: 28
Leptotyphlops dulcis dulcis — CROTHER 2000: 65
Leptotyphlops dulcis dissectus — CROTHER 2000: 65
Leptotyphlops dulcis dissectus — DIXON 2000
Leptotyphlops dulcis dissectus — TENNANT & BARTLETT 2000
Leptotyphlops dissectus — DIXON & VAUGHAN 2003
Rena dulcis rubella — DIXON & VAUGHAN 2003
Leptotyphlops myopicus — DIXON & VAUGHAN 2003
Rena myopica — ADALSTEINSSON, BRANCH, TRAPE, VITT & HEDGES 2009
Leptotyphlops sp. B — ADALSTEINSSON et al. 2009
Rena sp. B. — ADALSTEINSSON et al. 2009
Leptotyphlops dissectus — BATEMAN et al. 2009
Rena dissecta — ADALSTEINSSON et al. 2009
Leptotyphlops myopicus — VITE-SILVA et al. 2010
Rena dulcis — CROTHER et al. 2012
Rena dulcis rubellum — CROTHER et al. 2012
Rena dissectus — CROTHER et al. 2012
Rena dissecta — WALLACH et al. 2014: 631
Rena dulcis — WALLACH et al. 2014: 632
Rena myopica — WALLACH et al. 2014: 632
Rena dulcis rubella — CROTHER et al. 2017
Rena dissectus — CROTHER et al. 2017
Rena dulcis — FLORES-VILLELA et al. 2022
|Distribution||USA (Colorado, S Oklahoma and most of Texas) (DIXON & VAUGHAN 2003), Mexico (Quéretaro, Chihuahua, San Luis Potosí, Hidalgo, Coahuila)|
dissecta: USA (New Mexico, W Texas, Oklahoma), Mexico (Coahuila); Type locality: “road at the silver mines at Lake Valley, southern New Mexico”
dulcis: USA (Texas, S Oklahoma); Mexico (N Tamaulipas, C Nuevo Leon); Type locality: Between San Pedro and Comanche Springs, Texas.
myopica: Mexico (N Veracruz, probably N Puebla,
S San Luis Potosi northward across S Tamaulipas to
C Nuevo Leon, Hidalgo); Type locality: Savineto, near Tampico, Tamaulipas.
rubella: USA (S Texas), extreme NE Mexico (DIXON & VAUGHAN 2003); Type locality: “Uvalde, Texas”
supraorbicularis (invalid): Mexico (Chihuahua); Type locality: Colonia Juárez, Chihuahua, México.
|Types||Holotype: USNM 7296|
Holotype: ANSP 10752 [dissecta]
Holotype: BYU 30426, adult, collected by Virginia and Herman Hatch in April 1965 [supraocularis]
Syntypes: MCZ 4526, UMMZ 111306 [myopicus]
Holotype: MCZ 4584 [rubellum]
|Diagnosis||Rena dulcis (Baird & Girard, 1853). This species differs from other members in this group, except R. klauberi, by having supraoculars and undivided anterior supralabials (Dixon & Vaughan, 2003).|
The original description of rubella by Garman (1883 ) was based on a single specimen and had numerous errors. Garman reported erroneously 15 dorsal scale rows in R. dulcis, instead of 14 (as in other members of the genus Rena and most Leptotyphlopids); the rostral separating the nasals as a diagnostic character (as all Leptotyphlopids); 5 infralabials instead of 4 (as in all members of the genus Rena); and the anterior parietal (= parietal) being the only scale contacting the posterior labial, implying that in R. dulcis the posterior parietal (= occipital) also contacts the posterior labial (Stejneger, 1891). The latter condition, as mentioned by Stejneger, is only found on the left side of the holotype of R. rubella, and is variable in R. dulcis, contact only by the parietal being the prevalent condition.
In spite of broad overlap in ranges of variation, the number of middorsal scale rows was one of the criteria used by Dixon and Vaughan (2003: 14, 22: key) to distinguish 3 subspecies of R. dulcis: R. d. dulcis (210- 246), R. d. rubella (222-257), and an unnamed subspecies from Oklahoma (202-228). The other diagnostic character was dorsal coloration; “pinkish” for R. d. dulcis and “light to medium brown” for R. d. rubella. Because these 2 taxa show considerable overlap in middorsal counts, their distributional ranges are parapatric as delimited by Dixon and Vaughan (2003), and their middorsal scale counts decrease in a north to south clinal pattern, Flores-Villela et al. 2022 find no valid argument to recognize any subspecies within R. dulcis (FLORES-VILLELA et al. 2022).
Dixon and Vaughan (2003) in recognizing R. dissecta as a separate species from R. myopica. These authors based the recognition of these as 2 separate taxa primarily on their supposed differences in dorsal color, pinkish in R. dissecta and brown to black in R. myopica. Klauber (1940) reports specimens of R. dissecta ranging from pale to medium brown. FLORES-VILLELA et al. 2022 have examined additional specimens of R. dissecta not seen by Dixon and Vaughan (2003), and they observed grey (e.g., UTA R-54613) and brown (UTA R-45091) dorsal colors. We have also observed pinkish (UTA R-3149) and medium brown (UTA R-54555) specimens of R. myopica from Nuevo León and Tamaulipas, respectively. The number of middorsal scales was also stated by Dixon and Vaughan (2003) as significant in differentiating these taxa. Examination of additional material considerably expands the lower limit in the range of these scales for R. dissecta, from 220 to 213, providing considerable overlap between R. dissecta and R. myopica. Based on the lack of differences between the 2 taxa, FLORES-VILLELA et al. 2022 consider R. dissecta a junior synonym of R. dulcis (see their Table 2).
|Comment||Subspecies: Leptotyphlops dulcis myopicus has been elevated to a full species, L. myopicus, with one race, L. myopicus iversoni, by DIXON & VAUGHAN (2003). L. d. iversoni (SMITH et al. 1998) is here treated as valid species. However, FLORES-VILLELA et al. 2022 synonymized dissecta, rubella and myopica (again) with dulcis.|
Distribution: For (older) maps see Hahn 1979. For a map of the dulcis group see Villela-Flores et al. 2022 (although it’s black and white and all symbols look more or less the same). R. dissecta is not in Sonora fide Lemos-Espinal et al. 2019.
Group: the dulcis group of Leptotyphlops contains dulcis, bressoni, iversoni, klauberi, and segrega.The dulcis group of Leptotyphlops as defined by Klauber (1940), now allocated to the genus Rena (Adalsteinsson et al., 2009) is characterized by having a cream-colored ventral surface with scant dark pigmentation, lacking a sharply contrasting white spot on the snout or tail tip, and lacking a pattern of longitudinal lines on the dorsum. Flores-Villela et al. 2022 refer to the R. dulcis group those species having 10 scale rows around the tail.
Synonymy: S. tenuiculus was reported from Mexico (San Luis Potosi, Tamaulipas); Type locality: San Luis Potosi (city?), but not in San Luis Potosí fide Lemos-Espinal et al. 2018 (checklist SLP). The holotype of R. tenuicula lacks divided anterior supralabials, but has 10 scales around the tail. Based on our examination of the holotype of R. h. tenuicula (Stenostoma tenuiculum, MCZ 4519), and the considerable variation in middorsal scale counts, supraoculars and anterior supralabials exhibited by R. dulcis (Table 2), Flores-Villela et al. 2022 consider R. tenuicula as belonging to the R. dulcis group, but leave it in the synonymy of R. dulcis.
NCBI taxonID: 711327 [dissecta]
|Etymology||The specific name is the Latin word dulcis, meaning "sweet."|
The name myopicus is derived from the Greek word myops, meaning "near-sighted" and icus, a suffix denoting a condition, in reference to the position of the eye under the ocular scale.
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