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The status of Mexican and Southwestern United States blind snakes allied with Leptotyphlops dulcis (Serpentes: Leptotyphlopidae).

Abstract.--The taxonomic status of the blind snakes Leptotyphlops dulcis dulcis, L dulcis dissectus and L. dulcis myopicus was re-evaluated, based upon the study of 867 individuals from the United States and Mexico. The presence of either a single or a divided anterior supralabial was considered to be a conservative character; based on this character, the specimens were divided into two groups. Analysis of variance of total dorsal scales within these two groups, paired with Duncan's Multiple Range Test, suggests that these three taxa represent three full species. Within the group with a single anterior supralabial, L. dulcis comprises three races (L. dulcis dulcis, L dulcis rubellum and an as-yet-unnamed race in eastern Oklahoma). Within the group with a divided anterior supralabial, L. dissectus is monotypic and L. myopicus consists of two races (L. myopicus myopicus and L. myopicus iversoni). Chihuahuan individuals previously classified as L. dulcis supraocularis were reassigned to L. dissectus.

Resumen.--El estado taxonomico de las culebras ciegas Leptotyphlops dulcis dulcis, L. dulcis dissectus, y L. dulcis myopicus fue reevaluado basado en 867 individuos. La presencia de una escama supralabial singular o dividida se considera ser un caracter invariable, y con base en ese caracter los especimenes fueron divididos en dos grupos. Dentro de estos dos grupos, analisis de varianza del numero de escamas dorsales, en conjunto con la prueba de Duncan de rango mulitple, sugieren que estos tres taxa representan tres especies distintas. Dentro del grupo con una supralabial anterior singular, L. dulcis consiste de tres subespecies (L. dulcis dulcis, L. dulcis rubellum, y otra que se encuentra en la parte este de Oklahoma y que todavia no tiene nombre). Dentro del grupo con una supralabial dividida, L. dissectus es monotipica, y L. myopicus consiste de dos subespecies (L. myopicus myopicus y L. myopicus iversoni). Individuos de Chihuahua previamente clasificados como L. dulcis supraocularis fueron reasignados a L. dissectus.

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This project began as a review of the relationships between Leptotyphlops dulcis dulcis (Baird & Girard 1853), and L. dulcis dissectus (Cope 1896) as proposed by Smith & Chiszar (1993). Smith & Chiszar proposed that there was a relatively broad intergradation zone between the two taxa that extends along a line from Terrell County, Texas, north to Collingsworth County (SE corner of Texas panhandle) east to Cooke County, and more or less southwest to Maverick County, Texas (see Figure 1 of Smith & Chiszar 1993). The intergradation zone proposed by Smith & Chiszar contained 84 individuals of L. dulcis whose total dorsal scale count varied from 214-245, and only four of which had an anterior supralabial combination of 1/2 (an undivided anterior supralabial on one side, but divided on the other); L. dulcis typically has a 1/1 condition and L. dissectus 2/2.

The authors felt that the high variability of dorsal scale count indicated that further study was warranted. In addition, the taxonomic relationship between L. dulcis myopicus (Garman 1883) and L. dulcis dulcis in northeastern Mexico and southern Texas became of primary interest. A preliminary examination of the available Mexican specimens led to the conclusion that an examination of other taxa in Mexico would help clarify relationships; these taxa included L. bressoni Taylor 1939; L. maximus Loveridge 1932; L. dulcis iversoni Smith, Van Breukelen, Auth & Chiszar 1998; and L. dulcis supraocularis Tanner 1985.

Klauber (1940), summarizing the historical taxonomy of L. dulcis and L. myopicus, placed L. myopicus as a subspecies of L. dulcis, and indicated that he had found enough differences between the type specimen of L. dissectus and specimens of L. myopicus from Mexico to reinstate L. dissectus as a subspecies of L. dulcis. Klauber's arrangement was ignored by some herpetologists, who continued to consider L. myopicus and L. dulcis as full species (Smith 1944; Smith & Sanders 1952; Martin 1958), but was accepted by others (Schmidt 1953; Webb 1970; Hahn 1979; 1980). The latest work by McDiarmid et al. (1999) reviewed the nomenclatural history of L. dulcis and, in their comments section, supports Hahn's (1980) arrangement of recognizing three subspecies, L. dulcis dulcis, L. dulcis dissectus and L. dulcis myopicus.

An analysis of the character traits of the above three subspecies from throughout their respective distributions (Figure 1), suggests that there are three distinct morphotypes. Leptotyphlops dulcis dulcis typically has seven rows of pigmented mid-dorsal scales (pinkish in life) and a single anterior supralabial. There are occasional combinations of no supralabials on either side (fusion with the ocular scale), none on one side and one on the other (fusion on one side with ocular scale), one on one side and two on the other (divided supralabial on one side, not on the other), one over one on one side and single on the other (horizontal, vertical or slant division on one side), or two on each side (divided on both sides). Typically L. dulcis dissectus has seven pigmented mid-dorsal scale rows (also pinkish in life), with two anterior supralabials on each side of the head, and with some of the same variation of the supralabial character given above. Of 652 individuals of L. dulcis dulcis, L. dulcis dissectus and L. dulcis supraccularis examined from throughout their distribution, only 2.8% have any combination other than one or two supralabials on either side of the head. Of this 2.8%, eight individuals have one supralabial on one side, and two on the other. The remaining 10 individuals have any of the other combinations mentioned above. At most, eight of the 652 individuals might be confused as to taxon, based upon the supralabial character alone.

MATERIALS AND METHODS

A total of 867 specimens of Leptotyphlops were examined from throughout the range of the L. dulcis complex in Mexico and the southwestern U.S.A. (Figure 1). Total number of dorsal scales were counted from the posterior edge of the rostral to the tail spine. Scale rows were counted at the 10th dorsal posterior to the rostral, at midbody, and at 10 dorsals anterior to the vent. Scale rows around the tail were counted at approximately midtail. In addition, four aspects of head scalation were ranked (number-coded) as follows: number of anterior supralabials 2/2 (1), 1/2 (2), 1/1 (3), 0/1 (4), 0/0 (5); number of supraoculars 1/1 (1), 1/0 (2), 0/0 (3); complete separation of parietal scale from posterior supralabial by a postocular scale on both sides (1), touching on one side (2), touching on both sides (3) and number of rows of scales around tail 10 (1), 12 (2).

Material examined.--Acronyms of museums for the following specimens are given in the Acknowledgments section of this paper.

Leptotyphlops bressoni.--MEXICO: Michoacan. Airo, 18 mi SW, SM 14773; Apatzingan, 4.8 mi S, INHS 84586; Uruapan, EHT-HMS 5247 (now housed in INHS).

Leptotyphlops maximus.--MEXICO: Guerrero. Balsas, FMNH 1263; Chilpancingo, MCZ 33607; Ixtapan de la Sal, 14 mi S, KU 67640-41; Taxco, S km N, TCWC 7410. Mexico. Ixtapan de la Sal, 1 mi S, KU 67639. Morelos. Alpuyeca, TCWC 4109-11; Cuernavaca, TCWC 17167; Puente de Ixtla, 12 mi S, EHT-HMS 5246 (see above). Puebla. Acatlan, 30 mi S, INHS 6290; Acatlan, Km marker 302, Hwy 190, INHS 55026; Atencingo, 2 km W, INHS 46976.

Leptotyphlops dissectus.--MEXICO: Chihuahua. Colonia Juarez, BYU 15210, 19131, 30426-28, 32417; Galeana, 4.5 mi SE, UAZ 36294; General Trias, Centro, UNM 32487; Rancho San Francisco, KU 44264. Coahuila. Saltillo, 4 mi W, UIMNH 105478; San Pedro, MCZ 4592. USA: Arizona. Bisbee, UAZ 39557, CAS 190171; Douglas, AMNH 89335, UAZ 32286, 50868; Hwy 80, 5 mi SW Arizona/New Mexico state line, UTEP 18392; Portal, vicinity, AMNH 92867, 109007, INHS 9764; Portal, 3 mi W, SRSU 2971; Portal, 1.4 mi SW, AMNH 128230; Portal, 3.5 mi SW, MVZ 196864; Portal, 4.5 mi SW, AMNH 128229, UMMZ 123691; American Museum of Natural History Research Station, AMNH 111629, 112984, 120703; AMNHRS, 1 mi N, AMNH 99330; Sunny Flats Camp Ground, Chiracahua Mountains, MVZ 74262; Thatcher, BYU 2982; Sycamore Springs, ENE Tombstone, CAS 190172; Tombstone, 8 mi E, CAS 190170. Kansas. Clark Co., KU 20206; Meade Co. KU 20207. New Mexico. Carlsbad, State Bird Farm, UTEP 1525; Dry Cave Sink, UTEP 1529-30; Glenwood, 2.5 mi N, BYU 13909; Grant Co., UTEP 40 12; La Cruces, vicinity, KU 239, UTEP 11318; Rattlesnake Springs, UMMZ 121792-93; Roswell, 8 mi 5, 30.5 mi E, UNM 56958; Roswell, 4 mi N, 37 mi E, UNM 56957; Sherman, 5 mi NE, UTEP 4012. Oklahoma. Caldwell, Kansas, SE of, Oklahoma/Kansas state line, 0.4 mi 5, KU 204049-50, 1.2 km 5, KU 206211; Coopertown, UOMZ 23298; Fittstown, 1.5 mi W, UOMZ 27363; Lawton, 4 mi N, UOMZ 35537, 35544; Norman, UOMZ 3899, 27540, 23369; Teagarden, 1.6 mi E, UOMZ 13377, 25853-55; Wichita National Wildlife Refuge, UOMZ 26879; Yukon, 7 mi N, UOMZ 9791. Texas. Armstrong Co., Canyon, 20 mi E, SM 4269. Brewster Co., Alpine, SRSU 1476, 1534, 1853-54, 6284-85; Alpine, 19 ml 5, TCWC 72675; Big Bend National Park Basin, FMNH 27747-48; Big Bend National Park, Oak Creek, USNM 103649; Alpine, 8.4 mi E, Hwy 90, UTEP 15433. Jeff Davis Co., Eppenhaur Camp, Madera Canyon, TCWC 12995. Fort Davis, CAS 139503; Fort Davis, 8 mi W, SM 14388; Fort Davis, 7.6 ml 5, SM 13129; Fort Davis, 1.5 mi SSW, AMNH 126270; Fort Davis, 24.2 mi WSW, SM 14389; Fort Da vis, 10 mi NE, TTU 4748. Culberson Co., McKittrick Canyon, BYU 42087, SM 6287, UMMZ 125326. El Paso Co., El Paso, vicinity, UTEP 1200, 1721, 1862, 3504, 17187, 18299. Hudspeth Co., Hueco Mountains, 4.7 mi E jct. Hwys 62 and 2775, UTEP 11487; jct. Farm Rd. 192/1-20, 2.2 mi SE, UTEP 16313. Hutchinson Co., Borger, 3 ml W, CM 90287; Stinnet, 9 mi E, TNHC 10413, 10415, 10427-28, 10433, 10449-51, 10465, 10498, 10501, 10557, 10693, 10833, 10883, 10885, 10896-97, 10899, 10901, 10952, 10983-84, 11311-12, 111377, 11407-08, 11410-11, 11413, 11421-23, 11429, 11434-35, 11441, 11457, 11473, 11538. Oldham Co., Glenrio, 15 ml E, CM 48444. Potter Co., Amarillo, WTSU 923; Amarillo, Tascosa Road, WTSU 1912-15; TCWC 72571. Reeves Co., Balmorhea, UMMZ 84091, 96658; Pecos, ANSP 15651. Roberts Co., Miami, 34 ml N, AMNH 120614.

Leptotyphlops dulcis.--MEXICO. Coahuila Allende, 14 mi 5, TCWC 60788; San Juan de Sabinas, UMMZ 118941. Nuevo Leon. Agua-leguas, UNL 1174; Agualeguas/Sabinas Hidalgo, km 5 between, UNL 3807; Anahuac, 26.5 km NE, UNL 3718; Villa del Carmen, UNL 1111. Tamaulipas. Bagdad, USNM 46580; Santa Teresa, 2.9 ml 5, SM 14380; Santa Teresa, 9.6 mi N, SM 14837. USA: Oklahoma. Beckham Co., 6.4 mi S jct. Hwys 30/66, on 30, UOMZ 25851. Caddo Co., Fort Cobb, 2 mi E, KU 80934-36. Carter Co., Ardmore, 5 mi SE, UOMZ 23086-89; Ardmore, 6 mi SSW, UOMZ 26555-57. Choctaw Co., no specific locality, UOMZ 12658 (Webb 1970, believes this animal is from Denton, Texas). Commanche Co., no specific locality, UOMZ 13100; Cache, 5 mi NNE, UOMZ 35581-82; Fort Sill, Medicine Creek, UOMZ 35535; Lawton, 4 mi N, 35536, 35538-43, 35545- 53; Lawton, 9 mi NE, UOMZ 35554; Lawton, 9 mi W, UOMZ 35555- 63; Lawton, 18 mi WNW, UOMZ 35564-80; Quanali Parker Lake, UOMZ 26613; Wichita National Wildlife Refuge, UOMZ 13 101-05, 13107-12, 29107, 29845-46, 29388-8 9. Dewey Co., Camargo, 5 mi ENE, UOMZ 35375. Harmon Co., Elm Fork of Red River, 1 mi W Hwy 30, UOMZ 25827-28; Hollis, 6 mi 5, UOMZ 26045-49; Reed, vicinity, UOMZ 29252, 32606, 33800-01, SW corner of county, UOMZ 4522. Jefferson Co., Waurika, TCWC 72633-34, MWSU 20, 28, 1438. Kiowa Co., Cooperton, UOMZ 23297, 23327; Gotebo, UOMZ 588. Marshall Co., Madill, UOMZ 35378; Powell, 1 mi E, UOMZ 27534-35; Willis, 5 mi N, UOMZ 27351, 30737, 35079. Murray Co., Camp Classen, UOMZ 32487-88; Turner Falls, UOMZ 27537-38, 29051; Turner Falls, 1 mi E, UOMZ 26558-59; Turner Falls, 1.2 mi W, UOMZ 25868; Turner Falls, 2 mi NE, UOMZ 25046-47. Seminole Co., Seminole, USNM 198022-23, 258190-212. Tillman Co., no specific locality, UOMZ 30742. Texas. Aransas Co., Aransas National Wildlife Refuge, TCWC 5866, 81168. Archer Co., Archer City, TCWC 72708; Archer City, 12 mi N, TCWC 72693; Holiday, 6 mi 5, TCWC 72688; Holiday, 10 mi 5, TCWC 72684; Lake Kickapoo, TCWC 72641, 72690; Lake Kickapoo, 2 mi E, TCWC 72660; Lake Kickpoo, 4 mi E, TC WC 72683; Scotland, 1 mi N, TCWC 72653; Scotland, 1.5 mi 5, TCWC 72685, 72692; Wichita Falls, 20 mi SW, TCWC 72647; Wichita Falls, 8 mi 5, TCWC 72644, Wichita Falls, 9 mi 5, TCWC 72642-43; Windhorst, 4 mi N, TCWC 72689, 72691; Windhorst, 7 ml E, TCWC 72686; Windhorst, 5 mi NNE, TCWC 72687. Atascosa Co., Benton, vicinity, KU 8485; Somerset, SW of, SM 14788; Somerset, 8 mi SW, TCWC 3322. Austin Co., Bellville, 0.3 mi SE, TCWC 41543-44. Bandera Co., Medina, TCWC 15164; Medina, lOmiS, TCWC 15166; Medina, 10 mi SW, TCWC 15154-61; Medina, 10 ml W, TTU 217 (5); Medina, 13 mi W, TCWC 15167, 79944-45. Baylor Co., Seymour, TCWC 72676; Seymour, 15 mi N, 05 4490-91. Bee Co., Beeville, TCWC 66525; Skidmore, 7 mi W, TCWC 31208. Bell Co., Belton, 4 mi SE, TCWC 27353; Temple, 10 mi NW, TCWC 53464. Bexar Co., Boerne, 4.5 mi S, TCWC 67534, 67536; Helotes, 5 mi W, SM 3325, 6012; San Antonio SRSU 1611, TCWC 79215-24. Blanco Co., Johnson City, 2 mi N, TCWC 52048; Johnson City, 3 mi W, TCWC 68 137-40. Bosque Co., Kooperl, TCWC 181 95-96. Brazos Co., Bryan, 7 mi WSW, TCWC 34717-21; College Station, 2 mi SW, TCWC 27354. Brooks Co., Falfurrias, TCWC 20889; Falfurrias, 12 mi SW, TCWC 33523. Brown Co., Brownwood, 30 km N, TCWC 72709-10. Calhoun Co., Magnolia Beach, SM 14812, 14814-15; Magnolia Beach, 2 mi SSE, SM 1907-10, 1914; Magnolia Beach, 3 mi SSE, SM 14813; Port Lavaca, SM 14821,14823; Indianola, 8 mi SE, SM 2987. Cameron Co., Bluetown, SM 14803; Brownsville, UTAR 1596, EHT-HMS 397-403; Harlingen, 4 mi E, SRSU 1609; San Benito, TCWC 15857, 15861. Childress Co., Childress, 9.8 mi N, TCWC 61531. Clay Co., no specific locality, TCWC 72706; Beyers, 3 mi SE, TCWC 72638, 72646, 72651, 72656; Beyers, 4 mi SW, TCWC 72659, 72652, 72669; Beyers, 8 mi N, TCWC 72639; Beyers, 8 mi NE, TCWC 72635, 72649, 72654; Beyers, 8 mi SE, TCWC 72645, 72657; Beyers, 8 mi E, TCWC 72640; Henrietta, TCWC 72659; Henrietta, 1 mi E, TCWC 72694, 72636-37; Henrietta, 2 mi E, TCWC 72697; Henrietta, 2 mi W, TCWC 72696; Henrietta, 5 mi E, TCWC 72700; Henrietta, 7 mi E, T CWC 72698; Nocona, 8 mi NE, TCWC 72695. Coleman Co., Freese Dam, TCWC 65993-94, 65997, 660 14-17; Valera, 22 mi 5, Day Ranch, TCWC 18931-35. Colorado Co., Colombus, 1 mi W, 10 mi S, TCWC 61445-46. Concho Co., Eden, 4.3 mi E, TCWC 65995; Lipan Creek, 0.5 mi Njct Hwys 38 and 381, TCWC 65996. Crockett Co., Barnhart, 8 mi SE, UTAR 36890. Crosby Co., Crosbyton, 3 mi E, LACM 105230; Crosbyton, 5.5 mi E, UNM 25733-37, 40063; Kalgary, 7 mi NE, TTU 4044, 4423; 2.3 mi NW jct. Hwys 651 and 2794, TTU 4864. Denton Co., Denton, TCWC 66884. Duval Co., Freer, 15 mi NW, SM 12631. Edwards Co., Junction, 23 mi SW, TCWC 6015; Rock Springs, 26 mi NE, TCWC 4578-81; Rock Springs, 29 mi NE, TCWC 6016; Rock Springs, 24 mi NE, TCWC 7037-39; Rock Springs, 27.4 mi NW, TCWC 52258-68. Eastland Co., Ranger, 3 mi N, TCWC 5241. Erath Co., Stephenville, TCWC 14058. Falls Co., Marlin, TCWC 72879. Fayette Co., La Grange, 4 mi W, TCWC 31209. Garza Co., Justiceberg, 6 mi E, TTU 521; Post, 10 mi SE, TTU 507. Gillespie Co., Fredericksburg, TCWC 524 0. Goliad Co., Goliad, UTAR 30067. Gonzales Co., Palmetto State Park, WTSU 9912. Guadalupe Co., McQueeny Dam, WTSU 13823-24; Seguin, 2 km W, WTSU 14016. Harris Co., Tomball, TCWC 80505, 80507. Hays Co., Fern Bank Springs, TCWC 36381; Nance Ranch, TCWC 3324, 3326; San Marcos, 6 mi NE, TCWC 6013-14; San Marcos, 6 mi NW, TCWC 8696, 8698-99; Wimberly, 2 mi W, TCWC 7970; Wimberly, 4 mi E, TCWC 27355. Hidalgo Co., Mc-Allen, 3 mi 5, TCWC 18197-98; Mission, TCWC 21167. Hill Co., Aquilla Lake, TCWC 69914; Whitney Lake, TCWC 72165. Hood Co., Lipan, 2 mi E, TCWC 25130-34. Jack Co., Bryson, TCWC 77828. Jackson Co., Edna, EHT-HMS 404. Jeff Davis Co., Fort Davis, 26 mi WNW, TCWC 27917; Valentine, 13 mi E, SM 14373. Jim Wells Co., 4.4 mi S jct Hwys 625 and 44, TCWC 63404. Jones Co., Anson, 5 mi N., TCWC 38769. Kendall Co., Comfort, 6 mi E, TCWC 4582. Kerr Co., Hunt, 3 mi W, TCWC 15 169-70; Kerrville, 9 mi N, TCWC 3323. Kimble Co., Junction, vicinity, TCWC 9990. Kinney Co., Brackettville, SRSU 2671; Del Rio, 20 mi E, KU 80931. Kleberg Co., Kingsyule, TCWC 13909-12; Rivera TCWC 33524. Knox Co., Benjamin, TCWC 72707. La Salle Co., 0.8 mi S jct Hwys 72/97 on 97, TCWC 79977. Leon Co., Normangee, 6 mi NW, TCWC 5239. Live Oak Co., 1 mi Ejct Hwys 9 and 72, TCWC 38770. Llano Co., Buchanan Dam, TCWC 17052; Llano, 3 mi W, TCWC 64605-07; Liano, 23 mi 5, Klussmann Ranch, TCWC 64792, 69439, 80506. Lubbock Co., Lubbock, UMMZ 76192; Acuff, 4 mi N, TTU 7372; Lubbock, 3 mi W, TTU 9357. Mason Co., Mason, 8 mi SW, TCWC 31210; Mason, 10 mi 5, TCWC 31211. Matagorda Co., Ma d Island Slough, TCWC 60612. McCullough Co., 1.7 mi E Hwy 283, 6.2 mi N Hwy 1121, TCWC 65998. McMullen Co., Three Rivers, 20.7 mi SW, SM 14818; Whitsett, 6.8 mi SW, TCWC 36382. Medina Co., Bandera, 13 mi SW, TCWC 15165; D'Hanis, 1 mi 5, TCWC 49190; Hondo Air Force Base, TCWC 15162-63, 15168. Midland Co., Midland, UTEP 14716. Mitchell Co., Colorado City, 5 mi W, TCWC 72677-82. Montague Co., Lake Nocona, TCWC 72699, 72701-04; Saint Jo, 1 mi 5, 05 24578-82.Montgomery Co., Tamina, 6 mi E, SM 2986. Palo Pinto Co., BSA Camp Constantin TCWC 25296; Palo Pinto, 3 mi W, TCWC 72674. Pecos Co., 1.6 mi N jct. Hwys 190 and 349, UTEP 2661. Refugio Co., Refugio, TCWC 17503. Regan Co., Best, 12 miS, SRSU 1596-97; Big Lake, 12 mi 5, 9 mi W, TCWC 31367. Robertson Co., Mitchell Lake, TCWC 14055; New Baden, 13 mi NE, TCWC 14056. Runnels Co., Ballinger, 6 mi SE, TCWC 67366. San Patricio Co., Portland, TCWC 47127-30, 72877-78. San Saba Co., Gorman Falls, TCWC 44476-77. Scurry Co., 2.3 mi S jct. Hwys 84 and 1269, TTU 5056. Shacklefo rd Co., Albany, 8 mi N, TCWC 65059; Watt Mathews Ranch, SM 14816. Starr Co., El Sauz, 1.9 mi N, TCWC 62281; Rio Grande City, 3 mi E, EHT-HMS 403. Sutton Co., Sonora, 10.3 mi SW, SM 8379. Tarrant Co., Benbrook, TCWC 33525; Cresson, 4 mi NW, TCWC 18200. Terrell Co., Independence Creek, 4.6 mi 5, UNM 48696; Sheffield, 22 mi 5, TTU 2442a, 2442b. Throckmorton Co., Watt Mathews Ranch, SM 10315. Tom Green Co., San Angelo, TCWC 15855-56; Veribest, 5 mi W, TCWC 66050. Travis Co., Austin, TCWC 20720, UCM 24239, WTSU 3276, 8735. Uvalde Co., Concan, SM 14828; Uvalde, MCZ 4584; Uvalde, 8 mi N, TCWC 44188; 62078; Uvalde, 13 mi N, TCWC 44109, 49191. Val Verde Co., Baker's Crossing, 8.7 km N, UTAR 28907; Comstock, 23.5 mi N, UTAR 1235; Del Rio, SRSU 1855-56, TCWC 48607, 63688; Dolan Falls, TCWC 38291. Victoria Co., Victoria, TCWC 46545. Washington Co., Brenham, TCWC 14057, 57085; Navasota, 8 mi W, TCWC 6070 1-04. Webb Co., Laredo, TCWC 6017. Wichita Co., Iowa Park, 7 mi WNW, TCWC 72671; Lake Wichita dam TCWC 72705; Wichita Falls, TCWC 72672-73; Wichita Falls, 9 mi W, TCWC 72648. Williamson Co., Georgetown, 20 mi W, TCWC 52049.

Leptotyphlops cf. dulcis.--MEXICO: Hidalgo. Metzquititlan, 4.8 km N, TTU 5748; Metzquititlan, 8.5 km S, TTU 6228-29. Queretaro. San Juan del Rio, 2.2 mi S, UIMNH 64063, TCWC 38231-32.

Leptotyphlops myopicus.--MEXICO: Hidalgo. Huejutla, 6.9 mi WNW, LACM 131179-80. Nuevo Leon. No specific locality, TNHC 25020; Bustamante, UNL 3934-35; Chipinque, UNL 5542; Galeana, near, FMNH 30615; Horse Tail Falls, FMNH 30616-17, 39824, SM 11521, UIMNH 3793, UK 148600, UNL 2701-02, Ituribe, UMMZ 95207; Ituribe, 14.4 mi E, CM 90356; La Cienega, 3.6 mi W, CM 90357; Linares, 18 mi WSW, TCWC 53026; Linares-Galeana Road, UAZ 41743; Montemorelos, 2 km NW, TCWC 653, 885; Montemorelos, 20 mi N, FMNH 40252; Monterrey, vicinity, BYU 41893, UNL 40, 510, 1931, 2070, 2485-86, 3049, 3892, USNM 7297; Santa Catarina, 18 mi W, UIMNH 6389. Puebla. Huauchinango, 5 mi N, UIMNH 3794. San Luis Potosi. No specific locality, MCZ 4518; Chantol, 3.3 mi W, TCWC 59918-19; Colonia El Meco, TCWC 31496; El Naranjo, UMMZ 119282; Presa de Guadalupe, 0.5 mi S, TCWC 53025; Valles, 7 mi N, AMNH 67001-02. Tamaulipas. Acuna, 3.2 km S, UMMZ 101234; Chamal, 6 mi NW, SM 14409-10, 14531-32; Chamal, 9 mi WNW, UMMZ 110960; Cuidad Victoria, 35 mi E, S M 8771; Cuidad Victoria, 43 mi E, SM 8782; Cuidad Victoria, 49 mi E, SM 8372, 8777, 8781; Cuidad Victoria, 50.2 klm E, SM 8778; Gavilan, 3 mi NE, TCWC 49931-32; Gomez Farias, vicinity, SM 8773, 8775, 8779-80, 8783-88, 11518-20, 13143-46, 14533-48, TCWC 33527-32, 71141, UIMNH 62398, UMMZ 110961, 110963, 101233, USNM 198052, 248494-501; La Libertad, UNL 4559-60; Mante, UNL 4465, UIMNH 62398; Magiscatzin, vicinity, MCZ 45563; Marmolejo, 1 mi W, TCWC 58171-72; Ocampo, 21 km N, San Antonio, UMMZ 110962; Ocampo-Tula Road, km 32, UNL 5021-22; Rancho Carricitos, vicinity, TCWC 49918, 49925-27, 49929-30, 55060, 58060, 58062-63, 58073, 58076; San Carlos, vicinity, TCWC 49919-24,58115-17, 58121, 58 123-24; Savineto, near Tampico, MGZ 4526, UMMZ 111306; Soto la Marina-Casas Road, km 64, UNL 4912; Soto La Marina, 30 mi W, SM 14396-408; Tepehuajes, 6 km E, 8 km 5, TCWC 70391; Tinaja, 1.1 mi E, TCWC 38670, 49928; Vado del Mado, 0.3 mi N, SM 8770, 8776; Vado del Mado, 4 mi E, SM 8774, Vado del Mado, 10.6 mi E, SM 8772. Verac ruz. Huejutla, 3 km ENE, TTU 5749; Jalapa, TCWC 72670; Panuco, USMN 66886; Tanoyuca, UMMZ 69408.

RESULTS AND DISCUSSION

Leptotyphlops dulcis dulcis.--Total number of dorsal scales of 518 L. dulcis dulcis varied between 203-257 (mean 226.8). Because of the wide range in number of dorsal scales within the specimens examined, the specimens of L. dulcis dulcis were grouped into five samples, based on physiographic and biotic provinces (roughly north to south) and were analyzed separately (see Table 1, Figure 2). The sample means were compared with ANOVA (f = 42.08, df = 526, P = 0.0001) and Duncan's Multiple Range Test ([infinity] = 0.05). This analysis of the total number of dorsal scales revealed a significant difference between Sample 1 and the rest of the samples (Table 1, 2, Figure 2), and a relatively smooth north-south dine among samples 2, 3 and 4, with respective means of 227.6 for southern Oklahoma and north Texas, 226.6 for central Texas, and 224.6 for eastern Texas. Mean number of dorsals in Sample 5 was significantly greater than those of the other Samples (P < 0.05). Sample 5 represents a distinct population of L. du lcis that occupies extreme northeastern Mexico and southern Texas. The number of dorsal scales varies from 222-257 (mean 240. 1). This population warrants recognition as a race; the name L. dulcis rubellum Garman 1883:130, type locality, Uvalde, Texas, is thus resurrected for this population. Its distribution includes most of the south Texas brush country and northeastern Tamaulipas, Mexico.

Sample 1 is a population in east-central Oklahoma, near Seminole. This sample varies from 203-228 (mean 214.3) in total number of dorsal scales, the lowest number ever recorded for L. dulcis dulcis. The closest sample geographically to Sample 1 is from south-central Oklahoma (Sample 2); this sample has a total number of dorsal scales that varies from 210-246 (mean 227.6). The latter sample of L. dulcis dulcis is only 48 to 64 kilometers west of Sample 1. In addition, a single specimen of a L. dulcis dissectus-like individual with 215 dorsal scales occurs in sympatry with L. dulcis dulcis in Seminole; the low dorsal scale count and dissected anterior supralabials suggests some possible hybridization. Likewise, another L. dulcis dissectus-like specimen with 223 dorsal scales occurs 56 km south of Seminole. The Seminole sample is statistically distinct from other L. dulcis dulcis samples in having very low dorsal scale counts, and warrants subspecific recognition. Currently this population of L. dulcis remains u nnamed because there are distributional gaps to the west and south where no specimens exist.

Leptotyphlops dulcis supraocularis.--This subspecies was described by Tanner (1985) from the small village of Colonia Juarez (30[degrees] 20' N, 108[degrees] 07' W), just southwest of Casas Grandes, Chihuahua, Mexico. The type locality is approximately 127 air km SSE of the southwestern corner of the "bootheel" in southwestern New Mexico. The type description is based on six specimens. According to Tanner, the subspecies differs from L. dulcis dissectus by having elongate supraoculars in medial contact that nearly or completely separate the prefrontal and frontal scales. The interparietal is much larger than either the frontal or interoccipital, and is about the size of the fifth mid-dorsal scale. Total dorsal scales vary from 231-246 (mean 231.0).

Twenty-two specimens of L. dulcis dissectus from Graham and Cochise counties, Arizona, nine from Chihuahua, Mexico (including five paratypes of L. dulcis supraocularis), and two from Coahuila, Mexico, were examined. Tanner (1985) remarked that he had examined an additional specimen (KU 44264) from extreme northwestern Chihuahua, and, based upon its scale morphology, decided it was a typical specimen of L. dulcis dissectus. After examining the same specimen, the authors of the current study concur with that identification.

Two additional specimens of the Leptotyphlops dulcis dissectus-supraocularis complex were examined from Chihuahua (UNM 32487, General Trias Centro; UAZ 36294, 3.5 km SE Galeana). The first has the typical head scales of L. dulcis dissectus, while the second specimen has a slightly enlarged interoccipital scale with the remaining head scales similar to those of L. dulcis dissectus. One of the Coahuila specimens (MCZ 4592) is from San Pedro, and its head scale arrangement is similar to that of L. dulcis supraocularis; the other specimen (UIMNH 105478) is from 4 miles west of Saltillo, and its head scale arrangement is typical of that of L. dulcis dissectus. Tanner (1985) suggested that the Graham County, Arizona, specimen that he examined had characteristics of both L. dulcis dissectus and L. dulcis supraocularis. Of the 21 specimens from Cochise County, Arizona, six have typical L. dulcis dissectus head scales, 11 have slightly enlarged interoccipital scales, one has the supraoculars in medial contact but a no rmal interoccipital scale and three have damaged head scales and cannot be evaluated. Some members of the L. dulcis group examined from the state of Hidalgo, Mexico, have elongated supraoculars. There is enough head scale variation in individuals of L. dulcis dissectus outside of the type locality of L. dulcis supraocularis to suggest that this subspecies is not valid. Accordingly, all Chihuahuan specimens are placed with L. dulcis dissectus.

Leptotyphlops dulcis dissectus.--Of 135 L. dulcis dissectus examined, the total number of dorsal scales varied from 220-255 (mean 236.3). The Leptotyphlops dulcis dissectus specimens examined were originally divided into four small samples to determine if any dine exists from east to west. These samples varied little in their mean number of dorsal scales, but a slight dine exists with higher numbers in the west to lower in the east, the mean number of dorsal scales for southeastern Arizona is 244.2, adjacent New Mexico and west Texas 239.7, the Texas Panhandle 235.0, and Oklahoma, Kansas and Colorado 234.4. These four samples were subsequently regrouped into two larger samples (Samples 6 and 7, Figure 2) to compare a Great Plains sample against a Chihuahuan Desert sample. Again, little difference could be found between the two samples (t = 1.4, df = 63, 68, P = 0.192), with the Great Plains sample being slightly lower in mean number of total dorsal scales (234.8) than the Chihuahuan sample (238.5).

Relationship between Leptotyphlops dulcis dulcis and L. dulcis dissectus.--Based upon the current analysis, there does not appear to be an intergradation zone between L. dulcis dulcis and L. dulcis dissectus, as suggested by Smith & Chiszar (1993). The latter authors based their conclusions on an examination of only 19 individuals of L. dulcis dissectus from the Panhandle of Texas and Colorado, 32 L. dulcis dulcis from southern Oklahoma and central Texas, 81 individuals they considered as intergrades from west central and north central Texas, and one from Jefferson County, Oklahoma. Smith & Chiszar (1993) separated the two taxa only by the number of anterior supralabials present on either side of the head, one for L. dulcis dulcis and two for L. dulcis dissectus. One individual from Lubbock, Texas, with a 1/2 supralabial count was placed with L. dulcis dissectus because of its higher dorsal count (234). They also discussed other individuals from north Texas with 1/2 or 2/2 supralabial counts (refer to the dis cussion on supralabials above).

With the larger sample sizes in the present study, an analysis of dorsal scale counts does not support a broad intergradation zone between L. dulcis dissectus and L. dulcis dulcis. The number of dorsal scales is highly variable, and only large numbers of individuals from single localities will present a true measure of variation for a sample. For example, 42 individuals from the Texas Panhandle (Stinnett, Texas) of L. dulcis dissectus have a dorsal scale variation of 17 scales (225-242), 15 individuals of L. dulcis dulcis from San Antonio, Texas, vary 23 (219-241), 46 individuals from Ft. Sill, Oklahoma, vary 24 (219-242) and 25 individuals from Seminole, Oklahoma, vary 24 (204-228) scales.

It is proposed that Klauber was correct when he indirectly argued that these two taxa may represent sympatric species. The number of supralabials in blind snakes is a genetically conservative character, and any 1/2 condition of the supralabials of any individual may represent one of two possibilities: (1) an aberrant condition (seen rarely within the species) or (2) a hybrid between two species with parapatric distributions.

The 1/2 supralabial condition occurs in seven individuals near the contact zone between the two taxa, and in 10 other specimens scattered throughout their respective distributions. Of the seven individuals that show the 1/2 supralabial condition near the contact zone, five occur in the Fort Sill area of Oklahoma, and one each occurs in Clay and Montague counties, Texas, along the Red River. These seven individuals could be considered aberrant because they represent less than one per cent of the sample studied. However, the five Oklahoma individuals are approximately 20 air miles south of Ft. Cobb, a L. dulcis dissectus locality based on the 2/2 supralabials; four of these occur near Fort Sill, and one in Kiowa County, just northwest of Fort Sill. In addition, there is a single individual with 2/2 supralabials in Wichita County, Texas. Do these individuals represent L. dulcis dissectus or are they aberrant or hybrid individuals within L. dulcis dulcis? The number of dorsal scales are of no value in this determ ination because the numbers and ranges of dorsal scales found in samples of both taxa (see Table 1) widely overlap. Because there are so few individuals (less than 2%) that show supralabial variation within the two taxa, these individuals are considered to represent occasional hybrids between two species. Based on the observations of the present study, Leptotyphlops dulcis dissectus is recognized as a distinct species, Leptotyphlops dissectus, without recognizable subspecies.

Leptotyphlops dulcis rnyopicus.--Leptotyphlops dulcis myopicus is a Mexican subspecies (Figure 1) with a brown to almost black dorsal color pattern and a normal 2/2 condition of the anterior supralabials (with a rare variance of 1/1, 1/2 or 1 over 1/2 supralabials). A total of 178 individuals from American museums and from one museum in Monterrey, Mexico, were examined. These were originally treated as five samples (Figure 2, Table 1, 2, samples 8-12), based on biogeographic regions. Total dorsal scales varied between 192 and 236. Although the statistical two standard errors on either side of the mean of dorsal scales separate the lowland (11, 12) and highland samples (8-10) of L. dulcis myopicus (Figure 2), it may only reflect the grouping of the samples, and not be of biological significance in this case. Other sample arrangements were tried, including smaller samples from west (slope) to east (lowlands), which were not always significantly different from one another. The recently described population of L. dulcis iversoni was included as one of the samples (Sample 10), and was not found to differ in total mean dorsals from L. dulcis myopicus (P>0.05). Mean total dorsal scales of L. dulcis myopicus samples did not differ from one another (P>0.05), but combined, were significantly lower (P<0.05) than those of L. dulcis dissectus, which shares the 2/2 supralabial condition. Based upon its distinct differences, the race L. dulcis myopicus is raised to a full species.

The variational extremes of total dorsal scales of the five samples of L. myopicus (8-12) ranged from 24 to 32, slightly lower than the variation seen in the four L. dulcis (1-4) samples (26-36). The Sierra Madre Oriental slope (Samples 8 and 9) are more similar to each other in the mean number of dorsal scales than to the Tamaulipan lowland samples (11 and 12), which are almost identical to each other. The difference may reflect some genetic response to respective environmental conditions between slope and lowland.

Relationship between Leptotyphlops myopicus and L. dulcis iversoni.--As stated above, Leptotyphlops dulcis iversoni (Sample 10) has total dorsal scale numbers similar to those of L. myopicus samples from the slope, possibly reflecting the slope distribution of L. dulcis iversoni. The unusual head scale feature (absence of supraoculars), however, of L. dulcis iversoni separates it from all other individuals of L. myopicus. Of the 15 known individuals of this taxon (see Auth et al. 2000), 11 lack supraoculars, three have a single supraocular on one side and one specimen has a supraocular on each side, typical of L. myopicus myopicus. Does this latter specimen represent L. myopicus myopicus, or is it an aberrant L. dulcis iversoni? Are the specimens with one supraocular aberrant, or are they hybrids with L. myopicus, making L. dulcis iversoni a full species? Pending more specimens for examination (as in L. dulcis and L. dissectus) to better define the relationships between L. my opicus myopicus and L. myopicus i versoni, the present taxonomic arrangement is accepted, with L. muopicus iversoni retained as a subspecies.

Relationship between Leptotyphlops myopicus and L. dissectus.--The relationship between L. dissectus and L. mupicus is easily resolved. There are no L. dissectus with the seven mid-dorsal scale rows brown to black seen in L. myopicus, nor L. myopicus with the pink color on the same rows as seen in L. dissectus. In addition, there is little overlap in the number of dorsal scales between the two taxa (Figure 2, Tables 1, 2).The two available specimens of L. dissectus from Coahuila, Mexico, have 238 and 243 dorsal scales; the specimen with a count of 238 from 4 miles west of Saltillo is geographically nearest the westernmost locality of L. myopicus (a single specimen) in Nuevo Leon, Mexico, 18 miles west of Santa Catarina, with a dorsal scale count of 229. The airline distance between these localities is 53 km. Dorsal scale count alone is not an absolute criterion upon which to distinguish between these taxa. However, both taxa can be distinguished by dorsal scale count in combination with color of the 7 middors al rows (220-255 for L. dissectus, 7 rows pinkish, 195-236 for L. myopicus, 7 rows brown to black.

Klauber (1940) reported that the width of the fifth dorsal (counted from the rostral) was usually wider than the fourth in L. dissectus and seldom so in L. myopicus. The current analysis of this character found it highly variable in a large series of L. dissectus, and not sufficient to use as a diagnostic character. Klauber also stated that the occipital scale is split on at least one side in about 59% of the L. dissectus he examined, while no L. myopicus exhibited this condition. This character was not found to be useful.

Klauber (1940) indicated he had examined specimens of L. dissectus from Coahuila, Mexico, that were almost black in color. This suggests that they may have been formalin "burned", and not possessive of their true color. The two available specimens that were examined in the present study from Coahuila, Mexico were dull gray in alcohol, and more representative of L. dissectus The authors have been unable to confirm the presence of "true" L. myopicus in Coahuila. The two currently recognized subspecies, L. dulcis dissectus and L. dulcis myopicus, are clearly allopatric and, as there is no evidence of intergradation between them, it is suggested that they represent distinct species.

Leptotyphlops cf. dulcis from Queretaro and Hidalgo.-A final problem remains to be solved. Six specimens of a L. dulcis-like snake from two widely separated localities in Mexico, far south of the range of L. dulcis, were examined (Tables 1 and 2, Sample 5a; Fig. 1). Three individuals are from 3.5 km south of San Juan Del Rio, Queretaro, and three are from the vicinity of Metzquititlan, Hidalgo. They resemble typical Leptotyphiops dulcis in color, with a 1/i supraocular condition, no split occipital scales, and dorsal scale counts varying from 222 to 240 (mean 231.5). The specimens were not likely introduced by the potted plant trade, although the Queretaro individuals were found adjacent to the Pan American Highway to Mexico City (by E. A. Liner). The Hidalgo animals were collected a considerable distance from any normal route of commercial traffic, and probably represent a natural population. Sampling of tissues or blood from living individuals for DNA analysis may be the only solution to the identification of these unidentified populations.

Leptotyphlops bressoni and L. maximus.--Three individuals of L. bressoni and 14 L. maximus were examined for comparison with other taxa from Mexico. The dorsal scale counts for these individuals are given in Tables 1 and 2 (Samples 13 and 14). Their distributions are indicated in Figure 1, and nothing needs to be added to the summary of their detailed descriptions given by Klauber (1940), Loveridge (1932) and Taylor (1939), except for the variation of the dorsal scales.

Summary of taxonomic changes.--Based upon the evidence presented above, Leptotyphlops dulcis dissectus is removed from the synonymy of L. dulcis and the taxon is recognized as Leptotyphlops dissectus, without recognizable subspecies. Leptotyphlops dulcis myopicus is elevated to a full species, L. myopicus, with one race, L. myopicus iversoni. Leptotyphlops dulcis comprises two races, L. dulcis dulcis (southern Oklahoma and most of Texas) and L. dulcis rubellum (south Texas and extreme northeastern Mexico), and possibly a third race, as yet unnamed, from eastern Oklahoma.

Keys.--The following keys to the species and subspecies of blind snakes of the Leptotyphlops dulcis complex should be used with caution. In almost every case, any given sample of individuals from a single locality varied 24-26 scales in dorsal scale count. For this reason alone it is difficult to identify any species of Leptotyphlops that were examined during this study based on dorsal scale count, unless differences in head scalation are present. It is important to use geographic locality whenever possible.

The presence of individuals with differing head scalation on the right and left sides of the head is problematic. These individuals should be considered possible hybrids between species with parapatric distributions; otherwise, they may be regarded as aberrant individuals. Dorsal scale count and geographic locality should be taken into consideration when assigning identifications to these specimens.
KEY TO SPECIES OF BLIND SNAKES OF THE LEPTOTYPHLOPS DULCIS COMPLEX


1. Scale rows around tail 10 2
 Scale rows around tail 12 Leptotyphlops maximus

2. Anterior supralabials entire Leptotyphlops dulcis
 Anterior supralabials divided
 by vertical suture 3

3. Parietal and posterior
 supralabial separated by
 postocular Leptotyphlops bressoni
 Parietal and posterior
 supralabial in contact 4

4. Mid-dorsal scale rows pinkish
 in color, dorsal scales 220-255 Leptotyphlops dissectus
 Mid-dorsal scale rows brown to
 black in color, dorsal scales
 192-236 Leptotyphlops myopicus


KEY TO SUBSPECIES OF LEPTOTYPHLOPS DULCIS

Dorsal scales 210-246, mid-dorsal scale rows pinkish in color, southern Oklahoma, north, central and east Texas Leptolyphiops dulcis dulcis

Dorsal scales 222-257, mid-dorsal scale rows light to medium brown, south Texas, NE Tamaulipas/Coahuila Leptotyphiops dulcis rubelluin

Dorsal scales 202-228, Seminole, Oklahoma area Leptotyphiops dulcis ssp.

KEY TO SUBSPECIES OF LEPTOTYPHLOPS MYOPICUS

Supraoculars absent, central Tamaulipas Leptotyphiops myopicus iversoni

Supraoculars present, Monterrey, Nuevo Leon, Veracruz, Hidalgo, San Luis Potosi, southern Tamaulipas Leptotyphiops myopicus myopicus

[FIGURE 2 OMITTED]
Table 1.

Total dorsal scales by sample and taxon. Sample 1, Leptotyphlops dulcis
ssp. from Seminole, Oklahoma; Sample 2, L. dulcis dulcis from southern
Oklahoma and north Texas; Sample 3, L. dulcis dulcis from central Texas;
Sample 4, L. dulcis dulcis from east Texas; Sample 5, L. dulcis rubellum
from south Texas and NE Tamaulipas/Coahuila; Sample 5a, L. cf. dulcis
from the Mexican states of Queretaro and Hidalgo; Sample 6, L. dissectus
from Texas Panhandle, Oklahoma, Kansas and Colorado; Sample 7, L.
dissectus from west Texas, New Mexico, Arizona and Chihuadhua/Coahuila;
Sample 8, L. myopicus from Monterrey, Nuevo Leon; Sample 9 , L. myopicus
from Veracruz, Hidalgo and San Luis Potosi; Sample 10, L. myopicus
iversoni from central Tamaulipas, Sample 11, L. myopicus from San
Carlos, C. Victoria, Soto la Marina; Sample 12, L. myopicus from
southern Tamaulipas; Sample 13, L. maximus; Sample 14, L. bressoni.

SUPRALABIAL CONDITION 1/1

SAMPLE # n RANGE MEAN SD SE

1 23 202-228 214.3 6.9 1.44
2 218 210-246 227.6 7.4 0.50
3 177 210-242 226.6 7.0 0.53
4 42 213-239 224.6 6.6 1.03
5 58 222-257 240.1 8.8 1.16
13 14 216-235 225.4 6.4 1.71
5A 6 222-240 231.5 6.9 2.81

SUPRALABIAL CONDITION 2/2

SAMPLE # n RANGE MEAN SD SE

6 71 220-247 234.8 5.4 0.64
7 64 225-255 238.5 6.1 0.76
8 28 204-230 217.5 8.1 1.53
9 15 205-236 216.3 7.2 1.86
10 11 202-226 215.4 7.1 2.14
11 56 195-222 207.9 7.5 0.98
12 68 192-224 206.1 6.9 0.84
14 3 227-246 237.7 9.7 5.60

Table 2

Duncan's Multiple Range Test with confidence limits (alpha = 0.05) of
the samples of Leptotyphlops dulcis complex for total number of dorsal
scales arranged by supralabial condition. Samples grouped by a vertical
line are not statistically different from one another for the total
number of dorsal scales (See Table 1 caption for localities of samples
and taxon represented).

Supralabial condition 1/1 Supralabial Condition 2/2

 Sample 1 Sample 6
 Sample 5a Sample 7
 Sample 2 Sample 14
 Sample 3 Sample 8
 Sample 4 Sample 9
 Sample 13 Sample 10
 Sample 5 Sample 12


ACKNOWLEDGMENTS

For the loan of specimens we thank the following museums and persons: Academy of Natural Sciences, Philadelphia (ANSP), N. S. Gilmore; American Museum of Natural History AMNH), New York, D. Frost; Brigham Young University (BYU), Provo, Utah, J. W. Sites; California Academy of Sciences (CAS), San Francisco, J. V. Vindum; Carnegie Museum (CM), Pittsburgh, J. Wiens; Field Museum of Natural History (FMNH), Chicago, A. Resetar; Illinois Natural History Survey (INHS, now includes UIMNH), Urbana, C. A. Phillips; Los Angeles County Museum of Natural History (LACM), D. Kizirian; Museum of Comparative Zoology (MCZ), Cambridge, J. Rosado; personal collection, the late Ottys Sanders (OS); Museum of Southwestern Biology (UNM), Albuquerque, H. Snell; Midwestern State University (MWSU), F. S. Stangl; Museum of Vertebrate Zoology (MVZ), Berkeley, B. Stein; Natural History Museum, University of Arizona (UAZ), Tucson, R. Bradley; Strecker Museum (SM), Waco, D. Lintz; Sul Ross State University (SRSU), Alpine, J. Mueller; Texas Cooperative Wildlife Collection (TCWC), College Station, J. McEachran; Texas Natural History Collection (TNHC, now includes TTU), Austin, D. Cannatella; University of Kansas Natural History Museum (KU), J. Simmons; University of Michigan Museum of Zoology (UMMZ), G. Schneider; University of Oklahoma Museum of Zoology, Norman, L. J. Vitt; United States National Museum of Natural History (USNM), W. R. Heyer; University of Texas, Arlington, Reptiles (UTAR), J. Campbell; University of Texas, El Paso (UTEP), C. Lieb; Texas Tech University (TTU) Lubbock, R. Baker; Texas A&M University (WTSU) Canyon, F. Killebrew; Universdidad Autonomia Nuevo Leon (UNL), San Nicolas, D. Lazcano.

LITERATURE CITED

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Garman, S. 1883. The reptiles and batrachians of North America. Part 1, Ophidia. Mem. Mus. Comp. Zool., 8(3):xxxi + 185 p.

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Klauber, L. M. 1940. The worm snakes of the genus Leptotyphlops in the United States and northern Mexico. Trans. San Diego Soc. Nat. Hist., 8(18):87-162.

Loveridge, A. 1932. A new worm snake of the genus Leptotyphlops from Guerrero, Mexico. Proc. Biol. Soc. Washington, 45:151-152.

Martin, P. S. 1958. A biogeography of reptiles and amphibians in the Gomez Farias Region, Tamaulipas, Mexico. Misc. Pub., Mus. Zool. Univ. Michigan, 101:1-102, 7 pls.

McDiarmid, R. W., J. A. Campbell & T'S. A. Toure. 1999. Snake species of the world. Vol. 1. Washington, D.C. The Herpetologists League, ix + 511.

Schmidt, K. P. 1953. A checklist of North American amphibians and reptiles. Chicago, University of Chicago Press, 280 pp.

Smith, H. M. 1944. Snakes of the Hoogstraal Expeditions to northern Mexico. Zool. Ser., Field Mus. Nat. Hist., 29(8):135-148.

Smith, H. M. & D. Chiszar. 1993. Apparent intergradation in Texas between the subspecies of the Texas Blind Snake (Leptotyphlops dulcis). Bull. Maryland Herpetol. Soc., 29(4):143-155.

Smith, H. M. & O. Sanders. 1952. Distributional data on Texas amphibians and reptiles. Texas J. Sci., 4(2):204-219.

Smith, H. M., F. Van Breukelen, D. L. Auth & D. Chiszar. 1998. A subspecies of the Texas Blind snake (Leptotyphlops dulcis) without supraoculars. Southwestern Natur., 43(4):437-440.

Tanner, W. W. 1985. Snakes of western Chihuahua. Great Basin Natur., 45(4):615-676.

Taylor, E. H. 1939. On North American snakes of the genus Leptotyphlops. Copeia, 1939(1): 1-7.

Webb, R. G. 1970. Reptiles of Oklahoma. Norman, University of Oklahoma Press, 370 pp.

JRD at: jrdixon@tamu.edu
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Date:Feb 1, 2003
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