Subphylum Vertebrata Suborder Lacertilia/Sauria Scientific name Phrynosoma ditmarsi Rank Species | Phylum Chordata Infraorder Iguania | |
Similar Short‑tailed horned lizard, Horned lizard, Pygmy short‑horned lizard, Roundtail horned lizard, Mexican Plateau horned liz | ||
The rock horned lizard or Ditmars' horned lizard (Phrynosoma ditmarsi) is a species of phrynosomatid lizard endemic to Sonora in northern Mexico, south of the Arizona border. Bearing the shortest horns of all the horned lizards, it lives in thorn-scrub and deciduous Sinaloan woodlands. The rock horned lizard was "lost" to science for about 65 years. It has a unique habitat preference and limited distribution. It also had a very imprecise holotype locality record which made it difficult to locate. An extraordinary effort by Vincent Roth based on a cross-correlational analysis of gut contents from only three specimens led to its rediscovery.
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Etymology
Its specific name, ditmarsi, is in honor of Raymond Lee Ditmars, the first curator of reptiles of the Bronx Zoo, and a pioneer in herpetology.
Description
The rock horned lizard has its occipital and temporal horns reduced to flaring expansions. It has a deep and narrow occipital notch and a high postorbital ridge. The mandibles of Phrynosoma ditmarsi feature a large vertical expansion. It has a bare tympanum in the anterior neck fold posterior to a vertical row of four spines. One row of the rock horned lizard's lateral abdominal fringe scales is surrounded by prominent scales.