Results 161 to 170 of about 291,535 (278)

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

open access: yesThe 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   +1 more
wiley   +1 more source

Anatomy and variation in the paraphyletic Mosasaurus lemonnieri assemblage from the Craie phosphatée de ciply, Belgium

open access: yesThe Anatomical Record, EarlyView.
Abstract Nineteenth century excavations of the Ciply‐Malogne Phosphatic Chalk Formation in Hainaut, Belgium, yielded over 50 partial mosasaur skeletons, the majority of which were referred to the species Mosasaurus lemonnieri Dollo, 1889. In the years since, this taxon has experienced a complicated taxonomic history, and its exceptional hypodigm has ...
Henry S. Sharpe   +3 more
wiley   +1 more source

First reports on the relationship between the eggshell and bone mineralization in Rhinoclemmys punctularia punctularia embryos

open access: yesThe Anatomical Record, EarlyView.
Abstract Composed of various minerals, the eggshell provides ideal conditions for embryonic development, and understanding its composition and structure is essential for clarifying its relationship with bone formation. This study characterized the structure and mineral profile of the Rhinoclemmys punctularia punctularia eggshell in relation to ...
Igor Mathias Trindade Lemos   +8 more
wiley   +1 more source

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

open access: yesThe 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   +4 more
wiley   +1 more source

Histological description and bone compactness analysis of fossil (Aldabrachelys sp.) and extant Aldabra giant tortoise (Aldabrachelys gigantea) shell bone fragments

open access: yesThe Anatomical Record, EarlyView.
Abstract Aldabra Atoll, north of Madagascar and part of the Seychelles Outer Islands, is home to the Aldabra giant tortoise, Aldabrachelys gigantea, the only survivor of several species of giant tortoises that were once widespread on islands across the Western Indian Ocean.
Stefanie Herter   +9 more
wiley   +1 more source

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