Variações na fórmula dentária de Otaria byronia Blainville (Pinnipedia, Otariidae) no Pacífico: registro de um novo tipo de anomalia

Drehmer, César Jaeger; Dornelles, José Eduardo Figueiredo; Loch, Carolina

doi:10.4013/nbc.2009.41.04

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…Currently, estimates of total numbers of California sea lions range from 327,157 to 334,205 individuals, of which 80% are in the United States, 14% on the Pacific coast of the Baja California peninsula, and only 6% in the Gulf of California (Hernández-Camacho et al 2021). Similar results indicating population isolation resulting from environmental and climatic variability have been reported for other pinniped species (Brunner 2004; Drehmer 2005; Hoffman et al 2006; Túnez et al 2007; Artico et al 2010; Túnez et al 2010; Feijoo et al 2011; Oliveira et al 2017).…”

supporting

confidence: 86%

Skull shape and size changes in different subpopulations of the California Sea Lion (Zalophus californianus) in Mexico

Aguilar Medrano,

Cruz Escalona,

Payán Alcacio

et al. 2023

Journal of Mammalogy

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California sea lions (Zalophus californianus) are distributed along the Gulf of California and northeastern Pacific coast. Genetic studies have suggested the existence of 3 to 4 subpopulations in Mexico—1 on the Pacific coast of the Baja California peninsula (PC) and 3 in the Gulf of California—but the extent of this divergence is unclear, and it remains unknown if these subpopulations are morphologically distinct. In this context, we analyzed variation in skull size and shape of adult males between 5 and 13 years of age among 2 (north and central) of the 3 subpopulations of Z. californianus from the Gulf of California and the PC in Mexico. However, since the sample sizes for the 2 subpopulations in the Gulf of California were small, we merged all samples into 1 that we called the Gulf of California (GC) subpopulation. Artificial neural networks and geometric morphometrics were used to analyze skull images to quantify the extent to which these geographically separated subpopulations are undergoing morphological divergence. Our results find no significant differences in size in any view between the 2 subpopulations, but significant differences in the morphology of the dorsal, ventral, and lateral views of the skull between the 2 subpopulations. Overall, Z. californianus from the GC subpopulation have wider and lower skulls, extended back and outward with a more voluminous (bulky) nuchal crest, and narrow rostrum in comparison with skulls of Z. californianus from the PC subpopulation. Results concur with a previous genetic-based study, demonstrating that Z. californianus from both subpopulations in Mexico are diverging in their skull morphology and perhaps suggesting that they are experiencing different evolutionary pressures.

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supporting

confidence: 86%

Skull shape and size changes in different subpopulations of the California Sea Lion (Zalophus californianus) in Mexico

Aguilar Medrano,

Cruz Escalona,

Payán Alcacio

et al. 2023

Journal of Mammalogy

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“…Its occurrence in adult specimens and its morphological identity to the same structure described for the fossil genera Enaliarctos and Pteronarctos supports this claim. Some evidence of atavism in the dentition of Otaria byronia is well documented (DREHMER et al, 2004, DREHMER et al, 2009, so the nasolabialis fossa could also be subject to reversal (= taxic atavism) as observed in Pinnarctidion (BERTA; WYSS, 1994).…”

Section: Discussionmentioning

confidence: 99%

Interpretation of anatomical characters in phylogenetic analysis of Pinnipedia, with emphasis on Otariidae (Mammalia, Carnivora)

Sanfelice¹,

Drehmer²

2013

Biotemas

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ResumoInterpretação dos caracteres anatômicos em análises filogenéticas dos Pinnipedia, com ênfase em Otariidae (Mammalia, Carnivora). A partir da década de oitenta, a hipótese de que os pinipédios teriam uma origem comum ganhou espaço nos debates centrados na sistemática desse grupo. Todavia, o conhecimento restrito acerca da anatomia de muitas espécies e as frequentes variações nos estados de diversos caracteres dificultam a elucidação das relações filogenéticas dos pinipédios. Objetivou-se revisar os caracteres anatômicos do sincrânio e da dentição empregados nas análises filogenéticas, tendo por base os otarídeos Otaria byronia (n=25) e Arctocephalus australis (n=48). Algumas interpretações dos caracteres utilizados na literatura revelaramse questionáveis. Destacam-se: (1) forma e posição da tuberosidade pré-maxilar; (2) orientação da série de alvéolos pós-caninos maxilares; (3) fossa naso-labialis; (4) forma da sutura do jugal com o processo zigomático do temporal; (5) relevo do timpânico; (6) relação da altura do processo condilar com a série alveolar dos pós-caninos inferiores; (7) individualização do canal do aqueduto coclear e janela redonda; (8) separação de canais no meato acústico interno para os nervos cranianos VII e VIII; (9) presença de cíngulo lingual no terceiro incisivo superior; (10) desenvolvimento do metacônido do quinto pós-canino superior e (11) número de raízes do segundo ao quarto pós-caninos superiores e do quinto pós-canino inferior. Estas observações denotam a relevância e a necessidade de descrições anatômicas detalhadas dos pinipédios para o entendimento de sua evolução. Palavras-chave:Crânio; Dentes; Filogenia; Pinnipedia; Sistemática AbstractThe hypothesis that pinnipeds have a common origin gained support during the 1980s in discussions focused on the systematics of the group. However, the limited knowledge of the anatomy of several species and the frequent variation in several character states make it difficult to clarify the phylogenetic relationships of pinnipeds. Our purpose was to review the anatomical characters of the syncranium and dentition used in phylogenetic analyses by studying the otariids Otaria byronia (n=25) and Arctocephalus australis (n=48). Some interpretations of characters presented in the literature were found to be questionable, notably: (1) shape and 2175-7925.2013v26n2p185 Revista Biotemas, 26 (2), junho de 2013 186 D. Sanfelice e C. J. Drehmer position of the premaxillary tuberosity; (2) orientation of the maxillary postcanine alveoli; (3) naso-labialis fossa; (4) shape of the jugal contact with the zygomatic process of temporal; (5) relief and length of the tympanic bone; (6) relationship between the height of the condylar process in relation to the lower postcanine teeth alveoli; (7) individualization of the canal of the cochlear aqueduct and round window; (8) separation of the openings for the cranial nerves VII and VIII in the internal auditory meatus; (9) lingual cingulum on the third upper incisor; (10) development of the metaconid of the fift...

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“…A persistência de dentes decíduos é frequente em animais silvestres (Gioso et al, 2014), porém, a documentação de alterações dentárias em animais de vida livre é rara e esporádica. Alterações dentárias em mamíferos, como dentes supranuméricos ou ausentes e retenção de dentes decíduos são relatadas em leões-marinhos (Drehmer et al, 2004, Drehmer et al, 2009, lobos-marinhos (Drehmer e Ferigolo, 1996), cachorros-do-mato (Rossi Junior et al, 2013), morcegos (Rui e Drehmer, 2004), gambás (De Moraes et al, 2001), mão-pelada (Silva e Quintela, 2011;Bianchi et al, 2013), cachorros (Gaspar e Amaral, 1995;Lacerda et al, 2000), cavalos (Dixon et al, 2005) e gatos (Gawor e Niemiec, 2014;Langley-Hobbs et al, 2015). Aghashani et al (2016), estudando crânios de lince-pardo (Lynx rufus californicus), identificou a persistência de três incisivos mandibulares em duzentos e setenta e sete crânios analisados, sendo um crânio com dois dentes persistentes e um crânio com apenas um dente persistente.…”

Section: Discussionunclassified

Untitled

2021

Med. Vet. (UFRPE)

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Variações na fórmula dentária de Otaria byronia Blainville (Pinnipedia, Otariidae) no Pacífico: registro de um novo tipo de anomalia

Cited by 5 publications

References 10 publications

Skull shape and size changes in different subpopulations of the California Sea Lion (Zalophus californianus) in Mexico

Skull shape and size changes in different subpopulations of the California Sea Lion (Zalophus californianus) in Mexico

Interpretation of anatomical characters in phylogenetic analysis of Pinnipedia, with emphasis on Otariidae (Mammalia, Carnivora)

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