Embryonic development of Python sebae – I: Staging criteria and macroscopic skeletal morphogenesis of the head and limbs

Boughner, Julia C.; Buchtová, Marcela; Fu, Katherine; Diewert, Virginia M.; Hallgrímsson, Benedikt; Richman, Joy M.

doi:10.1016/j.zool.2007.01.005

Cited by 93 publications

(125 citation statements)

References 49 publications

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“…The timing for the establishment of amniote hatchling functional dentitions is well established. In crocodilians (extant sister taxon to Dinosauria) it typically occurs between 42% and 52% of the total incubation period (3) and at >51% in squamates (64,65,(67)(68)(69). In chicken (Gallus gallus domesticus), living dinosaurs, teeth primordia-none of which become functional-appear at 66% through incubation (98).…”

Section: Methodsmentioning

confidence: 99%

Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development

Erickson

Zelenitsky

Kay

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Birds stand out from other egg-laying amniotes by producing relatively small numbers of large eggs with very short incubation periods (average 11-85 d). This aspect promotes high survivorship by limiting exposure to predation and environmental perturbation, allows for larger more fit young, and facilitates rapid attainment of adult size. Birds are living dinosaurs; their rapid development has been considered to reflect the primitive dinosaurian condition. Here, nonavian dinosaurian incubation periods in both small and large ornithischian taxa are empirically determined through growthline counts in embryonic teeth. Our results show unexpectedly slow incubation (2.8 and 5.8 mo) like those of outgroup reptiles. Developmental and physiological constraints would have rendered tooth formation and incubation inherently slow in other dinosaur lineages and basal birds. The capacity to determine incubation periods in extinct egg-laying amniotes has implications for dinosaurian embryology, life history strategies, and survivorship across the Cretaceous-Paleogene mass extinction event.Dinosauria | teeth | embryology | Neornithes | extinction

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Section: Methodsmentioning

confidence: 99%

Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development

Erickson

Zelenitsky

Kay

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…In the last decade, however, the external development of several new species has been described and first attempts have been made to establish broad-scale phylogenetic analyses (e.g., Boughner et al, 2007;Sanger et al, 2008;Noro et al, 2009;Wise et al, 2009;Boback et al, 2012;Polachowski and Werneburg, 2013;Khannoon and Evans, 2015). In this regard, the SES-system (Werneburg, 2009) approach for the synthesis of the published information in the future Werneburg et al, 2013a,b).…”

Section: Phylogenetic Analysismentioning

confidence: 99%

Bony skull development in the Argus monitor (Squamata, Varanidae, Varanus panoptes) with comments on developmental timing and adult anatomy

Werneburg

Polachowski

Hutchinson

2015

Zoology

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“…Seven different embryonic stages were collected, beginning immediately after oviposition and continuing until 15 days after oviposition. The embryos were staged by external morphological features, following the staging table for the embryonic development of P. sebae [Boughner et al, 2007] and P. reticulatus by [Raynaud, 1972].…”

Section: Embryo Collectionmentioning

confidence: 99%

Development of Hemipenes in the Ball Python Snake <b><i>Python regius</i></b>

Leal¹,

Cohn²

2014

Sex Dev

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Within amniotes, external copulatory organs have undergone extensive morphological diversification. One of the most extreme examples is squamate (lizards and snakes) hemipenes, which are paired copulatory organs that extend from the lateral margins of the cloaca. Here, we describe the development of hemipenes in a basal snake, the ball python (Python regius). Snake hemipenes arise as a pair of lateral swellings on either side of the caudal part of the cloaca, and these paired outgrowths persist to form the left and right hemipenes. In non-squamate amniotes, external genitalia form from paired swellings that arise on the anterior side of the cloaca, which then fuse medially to form a single genital tubercle, the anlagen of the penis or clitoris. Whereas in non-squamate amniotes, Sonic hedgehog (Shh)-expressing cells of the cloacal endoderm form the urethral or sulcus epithelium and are required for phallus outgrowth, the hemipenes of squamates lack an endodermal contribution, and the sulcus does not express Shh. Thus, snake hemipenes differ from the genital tubercles of non-squamate amniotes both in their embryonic origins and in at least part of patterning mechanisms, which raises the possibility that hemipenes may not be direct homologs of the unpaired amniote penis. Nonetheless, we find that some developmental genes show similar expression patterns in snake hemipenes buds and non-squamate genital tubercles, suggesting that homologous developmental mechanisms are involved in aspects of external genital development across amniotes, even when these structures may have different developmental origins and may have arisen independently during evolution.

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Embryonic development of Python sebae – I: Staging criteria and macroscopic skeletal morphogenesis of the head and limbs

Cited by 93 publications

References 49 publications

Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development

Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development

Bony skull development in the Argus monitor (Squamata, Varanidae, Varanus panoptes) with comments on developmental timing and adult anatomy

Development of Hemipenes in the Ball Python Snake <b><i>Python regius</i></b>

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