The turtle shell is a complex structure that currently serves a largely protective function in this iconically slow-moving group [1]. Developmental [2, 3] and fossil [4-7] data indicate that one of the first steps toward the shelled body plan was broadening of the ribs (approximately 50 my before the completed shell [5]). Broadened ribs alone provide little protection [8] and confer significant locomotory [9, 10] and respiratory [9, 11] costs. They increase thoracic rigidity [8], which decreases speed of locomotion due to shortened stride length [10], and they inhibit effective costal ventilation [9, 11]. New fossil material of the oldest hypothesized stem turtle, Eunotosaurus africanus [12] (260 mya) [13, 14] from the Karoo Basin of South Africa, indicates the initiation of rib broadening was an adaptive response to fossoriality. Similar to extant fossorial taxa [8], the broad ribs of Eunotosaurus provide an intrinsically stable base on which to operate a powerful forelimb digging mechanism. Numerous fossorial correlates [15-17] are expressed throughout Eunotosaurus' skeleton. Most of these features are widely distributed along the turtle stem and into the crown clade, indicating the common ancestor of Eunotosaurus and modern turtles possessed a body plan significantly influenced by digging. The adaptations related to fossoriality likely facilitated movement of stem turtles into aquatic environments early in the groups' evolutionary history, and this ecology may have played an important role in stem turtles surviving the Permian/Triassic extinction event.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.cub.2016.05.020 | DOI Listing |
Animals (Basel)
November 2024
Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China.
The Chinese soft-shelled turtle () is an economically important species in aquaculture, and its growth pattern is characterized by significant sexual dimorphism. However, the underlying molecular mechanisms of this phenomenon have mostly been investigated in the gonadal tissues of , and there are no articles on sex differentiation from the brain of . Here, we analyzed transcriptomes of the brains of adult male and female using high-throughput Illumina sequencing technology, establishing a set of differential genes and differential transcription factors.
View Article and Find Full Text PDFSpace Sci Rev
December 2024
NASA Goddard Space Flight Center, Greenbelt, MD USA.
The Europa Imaging System (EIS) consists of a Narrow-Angle Camera (NAC) and a Wide-Angle Camera (WAC) that are designed to work together to address high-priority science objectives regarding Europa's geology, composition, and the nature of its ice shell. EIS accommodates variable geometry and illumination during rapid, low-altitude flybys with both framing and pushbroom imaging capability using rapid-readout, 8-megapixel (4k × 2k) detectors. Color observations are acquired using pushbroom imaging with up to six broadband filters.
View Article and Find Full Text PDFTierarztl Prax Ausg K Kleintiere Heimtiere
December 2024
Medizinische Kleintierklinik, Ludwig-Maximilians-Universität München.
Cell Stress Chaperones
December 2024
Unit for Reproductive Medicine - Clinic for Small Animals, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany. Electronic address:
Int J Mol Sci
November 2024
Key Laboratory for Aquatic Germplasm Innovation and Utilization of Jiangxi Province, School of Life Sciences, Nanchang University, Nanchang 330031, China.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!