Holbrookia subcaudalis ( Axtell 1956 )

Hibbitts, Toby J., Ryberg, Wade A., Harvey, Johanna A., Voelker, Gary, Lawing, A. Michelle, Adams, Connor S., Neuharth, Dalton B., Dittmer, Drew E., Duran, C. Michael, Wolaver, Brad D., Pierre, Jon Paul, Labay, Benjamin J. & Laduc, Travis J., 2019, Phylogenetic structure of Holbrookia lacerata (Cope 1880) (Squamata: Phrynosomatidae): one species or two?, Zootaxa 4619 (1), pp. 139-154 : 148-149

Holbrookia subcaudalis ( Axtell 1956)

Tamaulipan Spot-tailed Earless Lizard

( Fig. 9 )

Holbrookia lacerata subcaudalis Axtell 1956

Holbrookia subcaudalis Hibbitts et al. 2019 (this study)

Holotype. Texas Natural History Collection, University of Texas ( TNHC 20000 ); collected by Ralph W. Axtell on 6 June 1955 in plowed field 4.8 miles east northeast of Bishop , Nueces County, Texas, USA (27º 36’ N; 97º 45’ W) at an elevation of 75 feet .

Etymology. The name subcaudalis is derived from the latin word sub which means under or below and cauda which means tail. This refers to the dark spots on the underside of the tail in this species.

Distribution. Holbrookia subcaudalis is composed of all populations south of the Balcones Escarpment in Texas and west to the Sierra Madre Oriental in Coahuila, Nuevo Leon, and Tamaulipas, Mexico. They are absent from areas with sandy soils.

Diagnosis. Morphological description based on measurements and counts from 45 adults. This is a small, earless lizard with an average of 5 (1 – 10) black spots on the underside of the tail. The average snout-vent length (SVL) is 56 mm (31 – 72), paravertebral and dorsolateral body blotches are often separated. An average of 0.7 (0 – 6) blotches are fused out of an average of 6 (4 – 9) blotches. The blotches form four rows of transverse mostly circular blotches. The dark blotches on the rear legs are circular in shape and do not form into bands with the average number of leg blotches being 8 (4 – 14). Most individuals have black lateral spots on the abdomen and these average 2.6 (0 – 5). The average number of femoral pores on the left leg is 14 (10 – 19). The female body color is greenish yellow during the breeding season but they do not acquire orange on the throat in either sex.

Figures

FIGURE 9. Dorsal (top) and ventral (bottom) views of Tamaulipan Spot-tailed Earless Lizard (Holbrookia subcaudalis) holotype specimen collected by Ralph W. Axtell on 6 June 1955 and housed at Texas Natural History Collection, University of Texas (TNHC 20000).