My Journey...

These are the ramblings of a passionate photographer just wandering down the path of life. The photos are the real story, the accomplishment, the treasure. You are invited to come along for a spell. Enjoy the company. Enjoy the views!



All images and text on these pages are ©Copyright Douglas E. Wedman. All rights are reserved. Images and text may not be saved or used in any manner without the written consent of the photographer/author.

Saturday, April 30, 2011

Diversity Within The Species

As I continue my quest to complete my book on the lizard species of New Mexico, I periodically find myself in awe of the overall diversity in species that have adapted for life in the varried regions of the state. Recently, I have had the pleasure of close examination and study of the species Holbrookia maculata, the lesser earless lizard. The diversity across this species and across the sexes is impressive. And, I have yet to run across the longer-tailed variety of the extreme southwest corner of the state. (See my previous blog regarding my issues accessing this part of New Mexico.)

Holbrookia maculata ruthveni:
The adaptation of the narrow-ranged ruthveni subspecies to the unique white gypsum sands of Dona Ana and Otero counties of New Mexico through evolution of a bleached out appearance, is an obvious benefit. Combine the extent to which they blend with the substrate and their incredible ability to burrown into the sand in the blink of an eye and you certainly have a lizard poised for success!

2011_04_09_1599_HDR
White Sands

2011_04_29_1922
Subspecies ruthveni Specimen from White Sands

2011_04_29_1904
Burrowing under!

2011_04_29_1885
Periscope up!

Holbrookia maculata approximans:
Across most of the balance of New Mexico, and especially in the brown Mescalaro Sands, the subspecies is Holbrookia maculata approximans. This subspecies demonstrates dramatic sexual dimorphism. The female is quite vividly colored. Hager1 provides evidence that changes in coloration of the female are used as an indicator for males of her receptiveness to coppulation. Surely, this benefit must outweigh the negative camoflage aspects of this same coloration.

2011_02_26_7053
Subspecies approximans, brightly colored female from the Mescalaro Sands

2011_02_19_7024
Same female showing subdued (receptive) coloration

2010_08_08_5651
Subspecies approximans, a male from the Mescalaro Sands

References:
  1. Hager, S. B. 2001. The role of nuptial coloration in female Holbrookia maculata: evidence for a dual signaling system. Journal of Herpetology 35[4]:624-632.