Brevirostres
{{Short description|Taxon of reptiles}}
{{Paraphyletic group
| fossil_range = Late Cretaceous - Recent, {{fossil range|83.5|0}}
| image = Alligator from front.jpg
| image_caption = American alligator (Alligator mississippiensis)
| auto = yes
| taxon = Brevirostres
| authority = von Zittel, 1890
| includes =
| excludes =
}}
Brevirostres is a group of crocodilians that, as originally formulated, included alligatoroids and crocodyloids, but not gavialoids. Results of molecular phylogenetic analysis uniformly draw gavialoids and crocodyloids into a close relationship; in that case, Brevirostres becomes redundant with Crocodilia.
Members of brevirostres are crocodilians with small snouts, and are distinguished from the long-snouted gharials. It is defined phylogenetically as the last common ancestor of Alligator mississippiensis (the American alligator) and Crocodylus niloticus (the Nile crocodile) and all of its descendants.{{cite journal |last=Brochu |first=C. A. |year=2003 |title=Phylogenetic approaches toward crocodylian history |journal=Annual Review of Earth and Planetary Sciences |volume=31 |issue=31 |pages=357–97 |doi=10.1146/annurev.earth.31.100901.141308 |bibcode=2003AREPS..31..357B }} This classification was based on morphological studies primarily focused on analyzing skeletal traits of living and extinct fossil species, and placed the gharials outside the group due to their unique skull structure,{{cite journal | author=Holliday, Casey M. | author2=Gardner, Nicholas M. | year=2012 | title=A new eusuchian crocodyliform with novel cranial integument and its significance for the origin and evolution of Crocodylia | journal=PLOS ONE | volume=7 |issue=1 | pages=e30471 |doi=10.1371/journal.pone.0030471 |editor1-last=Farke |editor1-first=Andrew A |pmid=22303441 |pmc=3269432 |bibcode = 2012PLoSO...730471H | doi-access=free }} and can be shown in the simplified cladogram below:{{cite journal |doi=10.1080/02724634.1997.10011017 |last=Brochu |first=C.A. |year=1997 |title=A review of "Leidyosuchus" (Crocodyliformes, Eusuchia) from the Cretaceous through Eocene of North America |journal=Journal of Vertebrate Paleontology |volume=17 |issue=4 |pages=679–697 |jstor=4523857|bibcode=1997JVPal..17..679B }}
{{clade| style=font-size:85%;line-height:85%
|label1=Crocodylia
|1={{clade
|label2=Brevirostres
|2={{clade
}} }} }}
However, recent molecular studies using DNA sequencing render Brevirostres redundant with Crocodylia upon finding the crocodiles and gavialids to be more closely related than the alligators.{{cite journal |pmid=12775527 |year=2003 |last1=Harshman |first1=J. |title=True and false gharials: A nuclear gene phylogeny of crocodylia |journal=Systematic Biology |volume=52 |issue=3 |pages=386–402 |last2=Huddleston |first2=C. J. |last3=Bollback |first3=J. P. |last4=Parsons |first4=T. J. |last5=Braun |first5=M. J. |doi=10.1080/10635150309323 |url=http://si-pddr.si.edu/bitstream/handle/10088/6275/2003C_Harshman_et_al.pdf |doi-access=free |access-date=2021-07-19 |archive-date=2022-10-09 |archive-url=https://ghostarchive.org/archive/20221009/http://si-pddr.si.edu/bitstream/handle/10088/6275/2003C_Harshman_et_al.pdf |url-status=dead }}{{cite journal|last1=Gatesy |first1=J. |last2=Amato |first2=G. |year=2008 |title=The rapid accumulation of consistent molecular support for intergeneric crocodylian relationships |journal=Molecular Phylogenetics and Evolution|volume=48 |issue=3 |pages=1232–1237 |doi=10.1016/j.ympev.2008.02.009|pmid=18372192}}{{cite journal| author=Erickson, G. M.| author2=Gignac, P. M.| author3=Steppan, S. J.| author4=Lappin, A. K.| author5=Vliet, K. A.| author6=Brueggen, J. A.| author7=Inouye, B. D.| author8=Kledzik, D.| author9=Webb, G. J. W. | year=2012 | title=Insights into the ecology and evolutionary success of crocodilians revealed through bite-force and tooth-pressure experimentation | journal=PLOS ONE | volume=7 |issue=3 |page=e31781 |doi=10.1371/journal.pone.0031781|editor1-last=Claessens|editor1-first=Leon|bibcode = 2012PLoSO...731781E | pmid=22431965 | pmc=3303775| doi-access=free}}{{cite journal | author=Michael S. Y. Lee |author2=Adam M. Yates |date=27 June 2018 |title=Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil |journal=Proceedings of the Royal Society B |volume=285 |issue=1881 |doi=10.1098/rspb.2018.1071 |pmid=30051855 |pmc=6030529 |doi-access=free}}{{Cite journal|last1=Hekkala |first1=E. |last2=Gatesy |first2=J. |last3=Narechania |first3=A. |last4=Meredith |first4=R. |last5=Russello |first5=M. |last6=Aardema |first6=M. L. |last7=Jensen |first7=E. |last8=Montanari |first8=S. |last9=Brochu |first9=C. |last10=Norell |first10=M. |last11=Amato |first11=G. |date=2021-04-27 |title=Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus |journal=Communications Biology |language=en |volume=4 |issue=1 |page=505 |doi=10.1038/s42003-021-02017-0 |pmid=33907305 |pmc=8079395 |issn=2399-3642 |doi-access=free}} The new clade Longirostres was defined by Harshman et al. in 2003, and can be shown in the cladogram below:
{{clade| style=font-size:85%;line-height:85%
|label1=Crocodylia
|1={{clade
|label2=Longirostres
|2={{clade
}} }} }}
History
Brevirostres was first named by Karl Alfred von Zittel in 1890. Von Zittel considered Gavialis, the gharial, to be closely related to Tomistoma, the false gharial, and excluded them from the group. Tomistoma, as its name implies, is traditionally not considered closely related to Gavialis, but instead classified as a crocodylid. Under this classification, all members of Brevirostres are brevirostrine, or short-snouted. Recent molecular analyses support von Zittel's classification in placing Tomistoma as a close relative of Gavialis. If this classification is accepted, Brevirostres can be considered redundant with Crocodylia, as the two names would refer the same clade. Brevirostres would not, however, be a junior synonym of Crocodylia, as the two names have different definitions. {{cite journal |last=Brochu |first=C.A. |year=1999 |title=Phylogenetics, taxonomy, and historical biogeography of Alligatoroidea |journal=Memoir (Society of Vertebrate Paleontology) |volume=6 |pages=9–100 |doi=10.2307/3889340|jstor=3889340 }}