title: The jaw adductor muscle complex in teleostean fishes: evolution, homologies and revised nomenclature (osteichthyes: actinopterygii).
abstract: The infraclass Teleostei is a highly diversified group of bony fishes that encompasses 96% of all species of living fishes and almost half of extant vertebrates. Evolution of various morphological complexes in teleosts, particularly those involving soft anatomy, remains poorly understood. Notable among these problematic complexes is the adductor mandibulae, the muscle that provides the primary force for jaw adduction and mouth closure and whose architecture varies from a simple arrangement of two segments to an intricate complex of up to ten discrete subdivisions. The present study analyzed multiple morphological attributes of the adductor mandibulae in representatives of 53 of the 55 extant teleostean orders, as well as significant information from the literature in order to elucidate the homologies of the main subdivisions of this muscle. The traditional alphanumeric terminology applied to the four main divisions of the adductor mandibulae - A1, A2, A3, and Aω - patently fails to reflect homologous components of that muscle across the expanse of the Teleostei. Some features traditionally used as landmarks for identification of some divisions of the adductor mandibulae proved highly variable across the Teleostei; notably the insertion on the maxilla and the position of muscle components relative to the path of the ramus mandibularis trigeminus nerve. The evolutionary model of gain and loss of sections of the adductor mandibulae most commonly adopted under the alphanumeric system additionally proved ontogenetically incongruent and less parsimonious than a model of subdivision and coalescence of facial muscle sections. Results of the analysis demonstrate the impossibility of adapting the alphanumeric terminology so as to reflect homologous entities across the spectrum of teleosts. A new nomenclatural scheme is proposed in order to achieve congruence between homology and nomenclature of the adductor mandibulae components across the entire Teleostei.
authors.affiliation: Laboratório de Ictiologia, Museu de Zoologia da Universidade de São Paulo, São Paulo, Brazil. adatovo@gmail.com
authors.forename: Aléssio
authors.initials: A
authors.lastname: Datovo
authors.forename: Richard P
authors.initials: RP
authors.lastname: Vari
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005399:Fishes / Q000033:anatomy & histology* / Q000145:classification; D007568:Jaw / Q000033:anatomy & histology*; D008334:Mandible / Q000033:anatomy & histology; D018482:Muscle, Skeletal / Q000033:anatomy & histology
references.citation: Dev Growth Differ. 2008 Jun;50(5):339-55
references.pmid: 18430028
references.citation: J Morphol. 1990 Sep;205(3):269-295
references.pmid: 29865760
references.citation: Zoology (Jena). 2012 Apr;115(2):84-116
references.pmid: 22445572
references.citation: J Fish Biol. 2009 Nov;75(7):1601-14
references.pmid: 20738636
references.citation: Zoology (Jena). 2010 May;113(3):148-57
references.pmid: 20439154
references.citation: J Morphol. 1996 Aug;229(2):121-160
references.pmid: 29852585
references.citation: J Morphol. 1967 Feb;121(2):103-34
references.pmid: 6034527
references.citation: J Morphol. 2009 Aug;270(8):976-83
references.pmid: 19274745
references.citation: J Exp Zool B Mol Dev Evol. 2007 Sep 15;308(5):625-41
references.pmid: 17358013
references.citation: J Morphol. 2009 Mar;270(3):291-305
references.pmid: 19034917
references.citation: J Morphol. 2006 Feb;267(2):187-97
references.pmid: 16284943
references.citation: J Morphol. 2008 Oct;269(10):1169-80
references.pmid: 18473368
references.citation: J Morphol. 2010 Jul;271(7):814-25
references.pmid: 20235155
references.citation: J Morphol. 1976 Oct;150(2):399-422
references.pmid: 30261707
references.citation: BMC Evol Biol. 2009 Jan 30;9:24
references.pmid: 19183467
references.citation: J Morphol. 1982 Dec;174(3):283-312
references.pmid: 30089344
references.citation: J Morphol. 2009 Jun;270(6):645-61
references.pmid: 19107942
references.citation: BMC Dev Biol. 2008 Feb 28;8:24
references.pmid: 18307809
references.citation: J Morphol. 2010 Sep;271(9):1053-65
references.pmid: 20730919
references.citation: J Morphol. 2001 Jan;247(1):1-33
references.pmid: 11124683
references.citation: Anat Embryol (Berl). 2005 Apr;209(4):323-34
references.pmid: 15761723
references.citation: J Morphol. 1967 Feb;121(2):135-58
references.pmid: 6034528
references.citation: J Anat. 1998 Nov;193 ( Pt 4):481-94
references.pmid: 10029181
references.citation: J Morphol. 2000 Feb;243(2):193-208
references.pmid: 10658203
references.citation: Philos Trans R Soc Lond B Biol Sci. 1975 Jan 2;269(899):275-579
references.pmid: 234190
references.citation: J Exp Zool B Mol Dev Evol. 2011 Jan 15;316(1):10-20
references.pmid: 20922774
references.citation: J Struct Biol. 2001 Oct;136(1):46-52
references.pmid: 11858706
references.citation: J Morphol. 1989 Nov;202(2):129-150
references.pmid: 29865677
references.citation: Zoology (Jena). 2008;111(6):442-54
references.pmid: 18640016
references.citation: J Morphol. 1978 Dec;158(3):323-360
references.pmid: 30227701
references.citation: J Morphol. 1996 Sep;229(3):255-269
references.pmid: 29852592
references.citation: J Theor Biol. 2003 Aug 7;223(3):269-81
references.pmid: 12850448
references.citation: J Morphol. 1999 May;240(2):169-194
references.pmid: 29847871
references.citation: J Morphol. 1991 Dec;210(3):267-87
references.pmid: 1791628
references.citation: J Anat. 2008 Mar;212(3):211-28
references.pmid: 18304204
references.citation: J Morphol. 2007 Jun;268(6):457-84
references.pmid: 17372936
references.citation: J Morphol. 1948 Sep;83(2):181-94
references.pmid: 18886023