Longitudinal variation in the axial muscles of snakes

The axial muscles of snakes are notable for having long tendons within individual segments that span several vertebrae. Consequently, muscles that extend anteriorly have a constraint on their length as their origins are located closer to the skull. However, this and other aspects of longitudinal variation in axial muscle morphology are poorly documented either within or between species of snakes. For the anterior half of the trunk in 25 phylogenetically and morphologically diverse species of snakes, we compared patterns of segmentation and morphology of the m. spinalis (SP) muscle, which is one of the largest epaxial muscles in snakes that is used in most types of locomotion and while constricting prey. Among the species studied, mid-body segments of the SP muscle spanned from 9-46 vertebrae, whereas the most anterior segments spanned from 7-17 vertebrae. In all species examined, the anterior decreases in total span of SP segments resulted primarily from reduced length of the long anterior anterior tendon rather than contractile tissue. Furthermore, reductions in segmental length occurred at more posterior locations than were necessary based on lengths of the mid-body segments. Several modifications in SP segments were observed that resulted in reduced total span, some of which varied among taxa. The number of vertebrae anterior to the origin of the most anterior SP segment attachment was fairly uniform among snakes (usually 5-8) and may facilitate identifying a posterior boundary for a cervical region in snakes.

Name thesis:degree_name

MS

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Arts and Sciences: Biological Sciences

Grantor dc:publisher

University of Cincinnati

Year dc:date

2012

Author dc:creator

• Nicodemo, Philip, Jr.

Contributors dc:contributor

• Jayne, Bruce

• Biology
• Segmentation
• Longitudinal Variation
• Snakes
• Serial Homologues

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=ucin1346171520

OAI identifier oai:identifier

oai:etd.ohiolink.edu:ucin1346171520