An introduction to the osteology of the Mammalia /

Flower, William Henry

doi:10.5962/bhl.title.101537

Cited by 160 publications

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“…Museum collections were insufficient for these studies because carpal elements are frequently missing or lack defined articular surfaces due to this lack of ossification. In lieu of examining only the morphology of incompletely ossified and burr-shaped carpal elements in dissections, this study focused on the position of fibrous, uncavitated joints that surround individual carpal cartilages which usually encased a carpal ossification center (Flower, 1885;Eschricht and Reinhardt, 1866). Each fibrous joint indicates where joint cavitation and articular cartilage would form if a complete synovial joint were to develop (Archer et al, 2003).…”

Section: Methodsmentioning

confidence: 99%

“…By examining the position of these fibrous joints, the number of carpal elements could be determined, and the carpal-carpal and carpometacarpal articulations could be identified. Published reports of carpal element morphologies reveal considerable variability within the carpus of odontocetes (i.e., Flower, 1885;Kunze, 1912;Eales, 1954;Yablokov, 1974;Gihr et al, 1982), but a reasonably stable morphology within mysticetes (i.e., Flower, 1885;Burfield, 1920). This stable mysticete morphology is to display a total of six carpals, with four carpal elements in the proximal row nearest the radius and ulna, and two elements in the distal row ( Fig.…”

Section: Methodsmentioning

confidence: 99%

“…The proximal row of carpal elements in a cranial to caudal direction, are here referred to as the scaphoid, lunate, cuneiform, and pisiform as in archaeocetes. The two elements of the distal row are here referred to as the trapezoid, and unciform (Flower, 1885). The unciform is believed to be the fusion of C4 and C5 (Eales, 1954;Gihr et al, 1982;Rommel, 1990).…”

Section: Methodsmentioning

confidence: 99%

“…The unciform is believed to be the fusion of C4 and C5 (Eales, 1954;Gihr et al, 1982;Rommel, 1990). The trapezium (C1) is lost in extant cetaceans by fusion with metacarpal I and never appears as a distinct element, although metacarpal I frequently assumes the shape of a carpal element in odontocetes (Flower, 1885). The magnum (C3) was lost or fused with the trapezoid (C2; Gihr et al, 1982).…”

Section: Methodsmentioning

confidence: 99%

“…The evolution of hyperphalangy was traced in a phylogenetic context and characters were optimized onto previously published cetacean phylogenies. Several digit loss hypotheses (e.g., Flower, 1885;Kü kenthal, 1889;Turner, 1892;Kunze, 1912;Howell, 1930) were tested using data from published descriptions, dissections of extant taxa, and examination of osteological specimens and radiographs.…”

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Evolution of hyperphalangy and digit reduction in the cetacean manus

Cooper

Berta

Dawson

et al. 2007

The Anatomical Record

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Cetaceans (whales, dolphins, and porpoises) have a soft tissue flipper that encases most of the forelimb, and elongated digits with an increased number of phalanges (hyperphalangy). In addition, some cetaceans exhibit a reduction in digit number. Although toothed cetaceans (odontocetes) are pentadactylous, most baleen whales (mysticetes) are tetradactylous and also lack a metacarpal. This study conducts a survey of cetacean metacarpal and phalangeal morphologies, traces the evolution of hyperphalangy in a phylogenetic context, optimizes characters onto previously published cetacean phylogenies, and tests various digit loss hypotheses. Dissections were performed on 16 cetacean flippers representing 10 species (8 mysticetes, 2 odontocetes). Phalangeal count data were derived from forelimb radiographs (36 odontocetes, 5 mysticetes), osteological specimens of articulated forelimbs (8 mysticetes), and were supplemented with published counts. Modal phalangeal counts were coded as ordered and unpolarized characters and optimized onto two known cetacean phylogenies. Results indicate that digital ray I is reduced in many cetaceans (except Globicephala) and all elements of digital ray I were lost in tetradactylous mysticetes. Fossil evidence indicates this ray may have been lost approximately 14 Ma. Most odontocetes also reduce the number of phalangeal elements in digit V, while mysticetes typically retain the plesiomorphic condition of three phalanges. Results from modal phalangeal counts show the greatest degree of hyperphalangy in digits II and III in odontocetes and digits III and IV in mysticetes. Fossil evidence indicates cetacean hyperphalangy evolved by at least 7-8 Ma. Digit loss and digit positioning may underlie disparate flipper shapes, with narrow, elongate flippers facilitating fast swimming and broad flippers aiding slow turns. Hyperphalangy may help distribute leading edge forces, and multiple interphalangeal joints may smooth leading edge flipper contour. Anat Rec, 290:654-672, 2007. 2007 Wiley-Liss, Inc.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Evolution of hyperphalangy and digit reduction in the cetacean manus

Cooper

Berta

Dawson

et al. 2007

The Anatomical Record

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Diaphragm structure and function in the Florida manatee (Trichechus manatus latirostris)

Rommel

Reynolds

2000

Anat. Rec.

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Relative to many other mammals, little is known about the functional morphology of the four extant species of the order Sirenia. In this study, 166 Florida manatee (Trichechus manatus latirostris) carcasses fresh enough to collect detailed anatomical information were examined to describe the gross anatomy of the diaphragm. Our results show that the Florida manatee's diaphragm differs from those of other mammals in that it: lies in a dorsal plane, rather than in the more typical transverse plane; is located dorsal to the heart and does not attach to the sternum; and attaches medially at the "I"-shaped central tendon to bony projections extending ventrally from the vertebral bodies, forming two distinct hemidiaphragms. The manatee's transverse septum is a separate structure that lies at a right angle to the diaphragm and separates the heart from the liver and other viscera. The extreme muscularity of the diaphragm and the ability of manatees to adjust their position in the water column with minimal external movement suggest that diaphragmatic contractions may change the volume of each pleural cavity to affect buoyancy, roll, and pitch. We also hypothesize that such contractions, in concert with contractions of powerful abdominal muscles, may compress gas in the massive large intestine, and thereby also contribute to buoyancy control.

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Carpal development and morphology in archontan mammals

Stafford

Thorington

1998

J. Morphol.

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Carpal morphology and development in bats, colugos, tree shrews, murids, and sciurids were studied in order to homologize carpal elements. Prenatal coalescence of discrete cartilaginous templates with a loss of a center of ossification appears to be the most common method of reducing carpal elements in these mammals. Only bats and colugos showed postnatal ossification between discrete elements as a method of reducing carpal elements. Carpal morphology of tree shrews is more diverse than previously reported. Ptilocercus shows a highly derived carpal morphology that may be related to its relatively greater arboreality Dendrogale exhibits what is most likely the ancestral tupaiid carpal morphology. Carpal morphologies of Tupaia, Urogale, and Anathana are identical to each other. Carpal morphology differs between megachiropterans and microchiropterans. These differences may be related to different aerodynamic constraints between the suborders. The carpal morphology of microchiropterans is diverse and may reflect different adaptive regimes between microchiropteran families. Carpal morphology of the colugos shows both megachiropteran and microchiropteran characters. The function of these characters in colugos and bats (stabilization of the carpus in dorsiflexion) is proposed to be similar, although the locomotor roles may be quite different between these taxa.

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An introduction to the osteology of the Mammalia /

Cited by 160 publications

References 0 publications

Evolution of hyperphalangy and digit reduction in the cetacean manus

Evolution of hyperphalangy and digit reduction in the cetacean manus

Diaphragm structure and function in the Florida manatee (Trichechus manatus latirostris)

Carpal development and morphology in archontan mammals

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