Download Full Document - Mountain Boomer Music!
Share Embed Flag
Download ePaper

Download Full Document - Mountain Boomer Music!

Download Full Document - Mountain Boomer Music! Download Full Document - Mountain Boomer Music!

mountainboomer.com
from mountainboomer.com More from this publisher
07.04.2013 Views

this taxon is tentatively coded as having the same character state as that observed in G. silus. In other crotaphytids, the coloration of the tail and hindlimbs does not differ from that of the rest of the body. The presence of this juvenile coloration is treated as the derived state. In those species with strongly laterally compressed tails (C. bicinctores, C. dickersonae. C. grismeri, C. insularis, and C. vestigium), a pale white or cream stripe runs down the dorsal surface of the tail (Fig. 3 1 B, 32A-D). Presumably, the laterally compressed tail serves a display function and this white pattern may somehow enhance this role. The presence of a pale dorsal caudal stripe appears to be unique to these lizards as it was not observed in any of the outgroup taxa and is therefore considered to be the derived state. Reticulate Pattern (Characters 66, 67; Fig. 30C, 30D, 3 1 A-D, 32A-D, 33-35). -All male Crotaphytus, except some C. nebrius, have some form of white reticulation in the dorsal and/or gular pattern. Indeed, all Crotaphytus neonates have an extensive reticulated dorsal pattern, with some of the reticulations surrounding bla~k pigment. This is a condition very similar to that seen in adult C. reticrtlatus and C. antiquus of both sexes. The extent and placement of the reticulated pattern varies considerably between species resulting in somewhat bewildering interspecific variation. Nevertheless, a pair of discrete characters were obtained from this aspect of the color pattern. The first character (66) describes the presence or absence of a reticulate pattern in neonates. This condition is present in all Crotaphytus neonates, and is absent from Gambelia and the outgroups (although the number of outgroup species for which juveniles were examined is relatively small). Therefore, the presence of a neonatal pattern of white reticulations enclosing dark pigments is treated as the derived state. A second character (67) is the presence of small, almost granular, reticulations on the ventrolateral surface of the abdomen. This condition is present only in C. bicinctores and C. antiquus, although the abdominal reticulations of C. antiquus are slightly larger than those of C. bicinctores. Ventrolateral abdominal reticulations were not observed in the outgroup taxa; therefore, their presence is treated as the derived state. In Crotaphytus, there are two common dorsal pattern types, reticulation and spotting. It seems likely that spots are formed when reticulations have become fragmented. For example, in large C. vestig- OF CROTAPHYTID LIZARDS ium, the typical reticulated pattern of the hindlimbs may be fragmented on the dorsal portion of the femoral region, resulting in spots. The anterior and posterior surfaces of the leg retain their reticulated pattern. Thus, the spotted patteni that occurs on the dorsum of all Crotaphytus except C. reticulatus and C. antiquus may be the derived condition. This same situation applies to additional characters associated with reticulation. However, the dangers of polar- izing characters using ontogenetic methods are well known (de Queiroz, 1985; Mabee, 1989, 1993) and I present this scenario as a hypothesis and nothing more. The reticulated versus spotted adult dorsal body patterns are considered in the discussion of the white component of the dorsal pattern (see be- low). White Component of Dorsal Pattern (Character 68; Fig. 30-32).-The white component of the dor- sal pattern of crotaphytids is quite variable between species, but within species there is little variation. The two main dorsal pattern types present in adult Crotaphytus are reticulated and spotted. Crotaphy- tus antiquus and C. reticuiatus exhibit the reticulated pattern, while the remaining species of Crotaphytus have a pattern that incorporates white spots or dash- es. Crotaphytus vestigium and C. insularis (see be- low) each differ from the other spotted species in their own way. Crotaphytus vestigium has thin, white, transverse dorsal bands, (Fig. 32C). Axtell (1 972) noted the presence of similar banding in C. bicinc- tores from the northern portion of its range, which he attributed to the retention of the juvenile pattern. However, an examination of approximately 300 specimens of C. bicinctores in the California Acad- emy of Sciences collection revealed that the white bands present in juveniles change during ontogeny into the broad, pale orange bands characteristic of adults. In adults that are dark from preservative, these orange bands fade and sometimes appear to be broad white bands. Although females may oc- casionally retain the juvenile white bands until near adult size is attained, males do not and no adult C. bicinctores that were not dark from preservative had white transverse banding. Only C. insularis ap- proaches the condition of C. vestigium, with most specimens having broad, wavy dorsal lines or dashes and a few specimens having what appear to be wavy transverse dorsal bands (Fig. 32D). Although the wavy dashes present in C. insularis may be modified transverse dorsal bands, the C. insularis condition is treated as a separate character state and no apriori assumptions were made regarding the order of trans- formation. Because Crotaphytus and Garnbelia are

BULLETIN CARNEGlE MUSElJ M OF NATURAL HISTORY NO. 32

BULLETIN CARNEGlE MUSElJ M OF NATURAL HISTORY NO. 32

logo

products

Resources

Company

Terms of service
Privacy policy
Cookie policy
Cookie settings
Imprint
Change language
Made with love in Switzerland
© 2024 Yumpu.com all rights reserved

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!