Functional Morphology and Comparative Anatomy of Appendicular Musculature in CubanAnolisLizards with Different Locomotor Habits

AbstractThe Osteichthyes, including bony fishes and tetrapods, is a highly speciose group of vertebrates, comprising more than 42000 living species. The anatomy of osteichthyans has been the subject of numerous comparative studies, but these mainly concern osteological structures; much less attention has been paid to muscles. In fact, the most detailed and comprehensive myological comparative analyses that were actually based on a direct observation of representatives of various major osteichthyan groups were provided various decades by authors such as Luther, Kesteven and principally Edgeworth. The present work provides an updated discussion of the homologies and evolution of the osteichthyan mandibular, hyoid and hypobranchial muscles, based on the author's own analyses and on a survey of the literature, both old and recent. The risks of discussing muscle homologies on the basis of a single line of evidence, even when it concerns innervation or development, is emphasized. It is stressed than only by taking into consideration various lines of evidence (e.g. developmental biology, comparative anatomy, functional morphology, paleontology, molecular biology, experimental embryology, innervation and/or phylogeny) it is possible to establish well-grounded hypotheses of muscle homology.

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The Comparative Anatomy of the Nasal Tract and the Function of the Spermaceti Organ in the Physeteridae (Mammalia, Odontoceti)

Bijdragen tot de Dierkunde ◽

10.1163/26660644-04301004 ◽

1973 ◽

Vol 43 (1) ◽

pp. 93-112 ◽

Cited By ~ 40

Author(s):

E. J. Schenkkan ◽

P. E. Purves

Keyword(s):

Functional Morphology ◽

Comparative Anatomy ◽

External Respiration ◽

Extreme Pressure ◽

Deep Dive ◽

Symmetrical Structure ◽

Fat Depots ◽

The Right

The nasal complex of Kogia has been compared with that of Physeter and shown to be homologouswith that of less specialized ondotocetes. The nasal complex of the Physeterids is structurally related to that of the Platanistids and Ziphioids. The spermaceti organ unique to the Physeteridae forms a part of the functional morphology of the right naris and is not a bilaterally symmetrical structure like the melon of other odontocetes. Separation of the two nares in the Physeteridae is caused by the asymmetrical development of the spermaceti organ. In Kogia part of the musculature of the left naris actuates the opening of the right naris, a feature unique amongst the Mammalia. The right naris is not used in external respiration but forms an air reservoir subservient to phonationat extreme depths. The spermaceti organ assists in evacuation of the lungs prior to a deep dive. The fat depots of the spermaceti organ in Physeter and the spermaceti organ and adipose cushion in Kogia may serve to absorb nitrogen at extreme pressure. The air reservoirs could perform a useful hydrostatic function during the ascent from great depths.

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Filter feeding in Late Jurassic pterosaurs supported by coprolite contents

PeerJ ◽

10.7717/peerj.7375 ◽

2019 ◽

Vol 7 ◽

pp. e7375

Author(s):

Martin Qvarnström ◽

Erik Elgh ◽

Krzysztof Owocki ◽

Per E. Ahlberg ◽

Grzegorz Niedźwiedzki

Keyword(s):

Functional Morphology ◽

Late Jurassic ◽

Food Source ◽

Direct Evidence ◽

Comparative Anatomy ◽

Indirect Evidence ◽

Gut Contents ◽

Important Food ◽

Filter Feeding ◽

Important Food Source

Diets of pterosaurs have mainly been inferred from indirect evidence such as comparative anatomy, associations of co-occurring fossils, and functional morphology. Gut contents are rare, and until now there is only a single coprolite (fossil dropping), with unidentified inclusions, known. Here we describe three coprolites collected from a palaeosurface with numerous pterosaur tracks found in early Kimmeridgian (Hypselocyclum Zone) intertidal deposits of the Wierzbica Quarry, Poland. The specimens’ morphology and association to the tracks suggest a pterosaur producer. Synchrotron scans reveal numerous small inclusions, with foraminifera making up the majority of the identifiable ones. Other small remains include shells/carapaces (of bivalves, ostracods, and other crustaceans/arthropods) and bristles (some possibly of polychaete worms). The high density of the small shelly inclusions suggest that they were not accidently ingested, but constituted an important food source for the pterosaur(s), perhaps together with unpreserved soft-bodied animals. The combined evidence from the tracks and coprolites suggest a filter-feeding ctenochasmatid as the most likely tracemaker. If true, this significantly expands the bromalite record for this pterosaur group, which was previously only known from gastroliths. Moreover, this study also provides the first direct evidence of filter feeding in Jurassic pterosaurs and shows that they had a similar diet to the recent Chilean flamingo (Phoenicopterus chilensis).

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Functional significance of preserved color patterns of mollusks from the Gosport Sand (Eocene) of Alabama

Journal of Paleontology ◽

10.1017/s0022336000058911 ◽

1988 ◽

Vol 62 (01) ◽

pp. 83-87 ◽

Cited By ~ 4

Author(s):

Patricia H. Kelley ◽

Charles T. Swann

Keyword(s):

Functional Morphology ◽

Functional Significance ◽

Intraspecific Variability ◽

Color Pattern ◽

Color Patterns ◽

Historical Factors ◽

Life Mode ◽

Molluscan Fauna ◽

Excellent Preservation ◽

Architectural Constraints

The excellent preservation of the molluscan fauna from the Gosport Sand (Eocene) at Little Stave Creek, Alabama, has made it possible to describe the preserved color patterns of 15 species. In this study the functional significance of these color patterns is tested in the context of the current adaptationist controversy. The pigment of the color pattern is thought to be a result of metabolic waste disposal. Therefore, the presence of the pigment is functional, although the patterns formed by the pigment may or may not have been adaptive. In this investigation the criteria proposed by Seilacher (1972) for testing the functionality of color patterns were applied to the Gosport fauna and the results compared with life mode as interpreted from knowledge of extant relatives and functional morphology. Using Seilacher's criteria of little ontogenetic and intraspecific variability, the color patterns appear to have been functional. However, the functional morphology studies indicate an infaunal life mode which would preclude functional color patterns. Particular color patterns are instead interpreted to be the result of historical factors, such as multiple adaptive peaks or random fixation of alleles, or of architectural constraints including possibly pleiotropy or allometry. The low variability of color patterns, which was noted within species and genera, suggests that color patterns may also serve a useful taxonomic purpose.

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