Embryonic Development and Skeletogenesis of the Pharyngeal Jaw Apparatus in the Cichlid Nile Tilapia (Oreochromis niloticus)

Abstract

The evolution of a specialized pharyngeal jaw apparatus (PJA) has been argued to be the key evolutionary innovation that allowed the explosive adaptive radiation of cichlid fishes in East African lakes. Subsequent studies together with recent molecular phylogenies have shown that similar innovations evolved independently several times within the teleosts, which poses the questions: (1) how similar are the developmental mechanisms responsible for these changes in divergent taxa and (2) how did such complex features arise independently in evolution? A detailed knowledge of PJA development in cichlids and other teleosts is needed to address these questions. Here, we provide a detailed account of the development of the PJA in one species of cichlid, the Nile tilapia (Oreochromis niloticus), from the early segmentation and patterning of its embryonic precursors -pharyngeal arches 3 to 7 -to its ossification. We find that pharyngeal segmentation occurs sequentially from anterior to posterior during early segmentation stages through the mid-pharyngula period. We show a clear combinatorial code of Hox gene expression such that each posterior arch is defined by a distinctive Hox signature. Posterior arch chondrogenesis in tilapia is essentially complete by the end of the hatching period, and most elements become ossified over the next two days. Our results reveal that both the fusion of lower jaw bones and articulation between the neurocranium and upper jaws occur during post-embryonic development. Abstract end data should be: Anat Rec, 292:1780Rec, 292: -1800Rec, 292: , 2009. V V C 2009 Wiley-Liss, Inc.

Gene duplication in an African cichlid adaptive radiation

“…These include 40 S and 60 S ribosomal proteins (duplicated in R. “chilingali” and M. estherae ), claudin 29a ( M. estherae ), GTPase IMAP family member 7 ( P. similis ), C–type lectin domain family 4 ( M. estherae ), high-mobility group 20B (HMG20B) from HMG-box superfamily ( A. tweddlei ), and hox gene cluster genes (all species). Hox genes are important in the regulation of development, and have been found to be associated with differential jaw development in cichlid fishes [49,50]. An immunoglobulin light chain gene belonging to the largest gene family represented in this study was found duplicated in P. similis .…”

Development of the mandibular, hyoid arch and gill arch skeleton in the Chinese barb Puntius semifasciolatus: comparisons of ossification sequences among Cypriniformes

“…(a) Puntius semifasciolatus stages 1-6 are notochord length (L N ) and stages 7-18 are standard length (L S ); stages 12 and 13 are both 6·03 mm, but are different ages (Appendix); never ossifies: ebc5, hbc4, pbc4, pc. (b) Barbus barbus; *, unclear from Vandewalle et al (1992) in which specific epibranchials are ossifying; **, these are ossified elements that were not discussed by Vandewalle et al (1992) but ones that were observed in this study in an adult specimen (USNM 204120, 83.5 mm); the development of the fifth ceratobranchial bone in larval fishes (Gonzalez et al, 1996;Le Pabic et al, 2009). The 18 marker elements, representing the 18 stages of ossification observed in P. semifasciolatus, were the fifth ceratobranchial bone, premaxilla, anterior ceratohyal, urohyal, dorsal hypohyal bone, symplectic, interhyal bone, metapterygoid, subopercle, autopalatine, coronomeckelian, first basibranchial bone, first epibranchial bone, third basibranchial bone, third hypobranchial bone, first hypobranchial bone, third pharyngobranchial bone and second pharyngobranchial bone [ Fig.…”

Early development and replacement of the stickleback dentition

“…These studies have uncovered differences in the location of tooth fields, the arrangement and number of teeth in tooth families, and the positioning and modes of tooth replacement. The spatiotemporal pattern of early tooth positioning within developing tooth fields has also been studied in many of these models (Huysseune et al, 1998;Van der heyden and Huysseune, 2000;Debiais-Thibaud et al, 2007;Stock, 2007;Le Pabic et al, 2009;Atukorala and Franz-Odendaal, 2014) with major differences found in the sequence and pattern of early tooth formation. Collectively, these studies highlight the diversity of tooth patterning and replacement mechanisms among teleosts.…”