Results 101 to 110 of about 29,197 (258)

The “costly son” hypothesis: Sons exacerbate obstetrical dilemmas in humans and other mammals

The Anatomical Record, EarlyView.
Abstract Human childbirth has often been considered uniquely difficult among mammals, yet recent evidence suggests that obstructed labor and fetopelvic disproportion are widespread across placental mammals. Here, we propose the “costly son” hypothesis: because male offspring are typically larger at birth, they impose greater obstetric risk on mothers ...
Nicole D. S. Grunstra, Jonathan C. K. Wells   +1 more
wiley   +1 more source

Body mass and sex estimation from lower carnassial tooth morphometry in the endangered Iberian wolf (Canis lupus signatus): An ecomorphological analysis of sexual size dimorphism

The Anatomical Record, EarlyView.
Abstract The Iberian wolf (Canis lupus signatus) is an endangered subspecies characterized by highly fragmented populations and increasing human–carnivore conflict across the Iberian Peninsula. Although body mass strongly influences predator–prey dynamics and ecological performance, quantitative assessments of sexual size dimorphism (SSD) and body mass
Leonardo Cotts, Eduardo Rossener, Ricardo Moratelli, Maria da Luz Mathias, Oscar Rocha‐Barbosa   +4 more
wiley   +1 more source

Sexual dimorphism in a population of the Kinosternon integrum turtle from the Chihuahua desert, San Luis Potosí, Mexico

Acta Biológica Colombiana
Sexual dimorphism in Squamata is generally skewed towards males, which is explained by their need to defend territories against other conspecifics and compete for females during the breeding season. However, sexual dimorphism in turtles (Testudines) has
Christian Berriozabal-Islas, Rodolfo Guzmán-Ramírez , Ricardo Torres-Cervantes, Aurelio Ramírez-Bautista, Angel Ortiz-Reyes   +4 more
doaj   +1 more source

Assessment of intraspecific skull variation in the Campanian baenid turtle Plesiobaena antiqua

The Anatomical Record, EarlyView.
Abstract Baenids are freshwater paracryptodiran turtles with a fossil record ranging from the Early Cretaceous to the Eocene. The baenid Plesiobaena antiqua is the most common turtle in the Campanian (Late Cretaceous) Dinosaur Park Formation in Canada, but the apparent intraspecific variation remains poorly understood.
Scott Bellotti, Donald D. Brinkman, Serjoscha W. Evers, Walter G. Joyce, Yann Rollot   +4 more
wiley   +1 more source

Regional variability in skull sexual dimorphism: Olive baboons, blue monkeys, and vervets confirm the posterior region of the skull and the snout as opposite extremes of sex differences in Old World monkeys

The Anatomical Record, EarlyView.
Abstract This study, alongside prior work on crab‐eating macaques with O'Higgins, investigates regional variation in skull sexual dimorphism across different species of Old World monkeys. Findings reveal consistent patterns: the posterior skull regions (mandibular vertical ramus, chondrocranium and, possibly, the cranial vault) exhibit lower dimorphism,
Andrea Cardini
wiley   +1 more source

Redescription of †Eobrasilia coutoi (Metatheria: Polydolopimorphia), a unique sclerocarpophagous metatherian from the Palaeogene of South America: Systematic affinities, and paleoecological and evolutionary implications

The Anatomical Record, EarlyView.
Abstract The ‘Palaeogene strata’ of the Itaboraí Basin (upper Paleocene‐lower Eocene), Southeastern Brazil, has preserved 29 genera and almost 50 species of metatherians (about 65% of its mammalian diversity). Among them, Eobrasilia coutoi Simpson, 1947 is the most enigmatic due to its quite fragmentary nature.
Leonardo M. Carneiro, Hugo Bampi, Ana C. Bernardes‐Dias, Lidiane Asevedo, João P. P. Araújo, Matheus R. Arêas, Alessandra S. Machado, Ricardo T. Lopes, Rafael C. Silva, Marina B. Soares, Gustavo R. Oliveira   +10 more
wiley   +1 more source

First evidence of a mandibular crest in Brasileodactylus Kellner, 1984 (Pterosauria, Pteranodontoidea, Anhangueridae), with comments on pterosaur headcrests

The Anatomical Record, EarlyView.
Abstract Brasileodactylus araripensis Kellner, 1984, is a toothed pterosaur from the Lower Cretaceous Romualdo Formation of the Araripe Basin, Brazil. Traditionally regarded as crestless, the species has been central to debates on anhanguerid taxonomy, as most members of the clade possess well‐developed sagittal cranial or dentary crests.
Anderson da Silva Nascimento, Rubi Vargas Pêgas, Alessandra Silveira Machado, Ricardo Tadeu Lopes, Fabiana Rodrigues Costa   +4 more
wiley   +1 more source

Size and shape variability in the skull of Myotis nigricans (Schinz, 1821) (Chiroptera: Vespertilionidae) from two geographic areas in Brazil

Brazilian Journal of Biology
We present a quantitative analysis of sexual dimorphism and geographic variation in the skull of Myotis nigricans (Schinz, 1821) assessed by geometric morphometrics.
R. Bornholdt, LR. Oliveira, ME. Fabián
doaj   +1 more source

Hormonal control and signaling of the testis of the bat Molossus molossus during the processes of testicular maturation, regression, and recrudescence

The Anatomical Record, EarlyView.
Abstract Molossus molossus, a species of neotropical bat belonging to the Molossidae family, has an annual reproductive cycle that includes two peaks of spermatogenic activity, one in April and another in September, and a period of total testicular regression in December.
Emília M. Soares, Juliana F. Ferraz, Cornélio S. Santiago, Larissa P. R. Venâncio, Arlindo G. Macedo‐Junior, Sebastião R. Taboga, Mateus R. Beguelini   +6 more
wiley   +1 more source

Y-Linked Copy Number Polymorphism of Target of Rapamycin Is Associated with Sexual Size Dimorphism in Seed Beetles. [PDF]

Mol Biol Evol, 2023
Kaufmann P, Wiberg RAW, Papachristos K, Scofield DG, Tellgren-Roth C, Immonen E.   +5 more
europepmc   +1 more source