Middle Ear Morphology of Lemur variegatus

Conroy, Glenn C.; Wible, John R.

doi:10.1159/000155829

Cited by 35 publications

(3 citation statements)

References 4 publications

(4 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ventral surface of the petrosal is scoured by a slight transpromontorial sulcus. This sulcus corresponds to direct contact by the ICA of non-artiodactylan mammals [52][53][54][55][56][57]; however, in the adult alpaca, the ICA does not make direct contact with the petrosal. The presence of a transpromontorial sulcus in adult alpacas may be an effect of arterial reduction during ontogeny (see below).…”

Section: Methodsmentioning

confidence: 99%

Cranial arterial patterns of the alpaca (Camelidae:Vicugna pacos)

O’Brien¹

2017

R. Soc. open sci.

View full text Add to dashboard Cite

Artiodactyl cranial arterial patterns deviate significantly from the standard mammalian pattern, most notably in the possession of a structure called the carotid rete (CR)—a subdural arterial meshwork that is housed within the cavernous venous sinus, replacing the internal carotid artery (ICA). This relationship between the CR and the cavernous sinus facilitates a suite of unique physiologies, including selective brain cooling. The CR has been studied in a number of artiodactyls; however, to my knowledge, only a single study to date documents a subset of the cranial arteries of New World camelids (llamas, alpacas, vicugñas and guanacoes). This study is the first complete description of the cranial arteries of a New World camelid species, the alpaca (Vicugna pacos), and the first description of near-parturition cranial arterial morphology within New World camelids. This study finds that the carotid arterial system is conserved between developmental stages in the alpaca, and differs significantly from the pattern emphasized in other long-necked ruminant artiodactyls in that a patent, homologous ICA persists through the animal's life.

show abstract

Section: Methodsmentioning

confidence: 99%

Cranial arterial patterns of the alpaca (Camelidae:Vicugna pacos)

O’Brien¹

2017

R. Soc. open sci.

View full text Add to dashboard Cite

show abstract

“…The significance of this variation for primate systematics will not be clear until we have a better understanding of variation in the carotid canals of modern lemuroids. Conroy and Wible (1978) have shown that the promontory canal does not always carry a promontory branch of the internal carotid artery in extant lemuroids, and Hill (1953) found that the stapedial canal in Tarsius does not always house a stapedial branch of the internal carotid artery. These discoveries do not bear directly on the systematic interpretation of fossils, which are based on the canals in any case, but they do affect our interpretation of possible functional differences between the carotid circulatory patterns of various living and fossil prosimians.…”

Section: Auditory Regionmentioning

confidence: 99%

Cranial morphology and adaptations in Eocene Adapidae. II. The Cambridge skull of Adapis parisiensis

Gingerich

Martín

1981

American J Phys Anthropol

View full text Add to dashboard Cite

One of the most complete skulls of the early primate Adapis parisiensis is in the collection of the Department of Zoology, Cambridge University. This exceptionally well-preserved male skull, from Quercy in southern France, is important in showing relatively small orbits that are highly convergent, a distinct ethmoid component in the medial orbital wall, very small infraorbital foramina, a well-preserved auditory region with the stapedial canal about twice the diameter of the canal for the promontory artery, and a well-preserved braincase 8.8 cm3 in endocranial volume. The frontal lobe of the brain in the Cambridge skull described here is less expanded than that reported previously in a British Museum skull. The average body weight OfAdapisparisiensis is estimated to have been about 2.0 kg, and that of Adapis magnus is estimated to have been about 8.4 to 9.0 kg. The encephalization quotient (EQ) ofAdapisparisiensis is estimated to have been 0.45, which is well below the range found in modern prosimians. There is some indication that the size of the foramen magnum has increased with increasing brain size during primate evo1ution.Adapisparisiensis appears to have been a medium-sized, visually oriented, diurnal, sexually dimorphic arboreal folivore.

show abstract

“…In modern lemurs that possess intact internal carotid systems, such as Eulemur and Lepilemur, ossification of the canal tends to be less complete, and the artery's track across the promontorium is mostly unenclosed by bone. Some notion of the variation found in extant lemurs can be gained by examining the schematic drawings of Szalay and Katz (1973) (see also Conroy and Wible, 1978). There are few known cranial specimens of adapids (e.g., Leptadapis) with well-preserved basicrania, and the range of variation in this group remains unclear.…”

Section: Discussion With These Features and Identifications In Mindmentioning

confidence: 99%

Skull of early EoceneCantius abditus (primates: Adapiformes) and its phylogenetic implications, with a reevaluation of ?Hesperolemur?actius

Rose

MacPhee

Alexander

1999

Am. J. Phys. Anthropol.

View full text Add to dashboard Cite

A substantially complete skull and mandible of the primitive adapiform Cantius is reported from the Early Eocene Willwood Formation of Wyoming. The mandible contains an almost complete lower dentition in which the lower incisors are strongly inclined and have spatulate crowns, I(2) is larger than I(1), and the canine is large and projecting. The cranium shares many features with those of Notharctus and Smilodectes but differs in having nasals that broaden proximally. Presence of a prominent canine and strong sagittal crest may indicate that it represents a male. The basicranium preserves auditory structures almost identical to those in extant noncheirogaleid lemurs, including a large bony tube for the stapedial artery and a small, open sulcus for the distal portion of the promontorial artery. The dentition is sufficiently primitive to be compatible with a relationship to either strepsirrhines or anthropoids, but the anatomy of the auditory region is more consistent with either specific relationship to lemurs or, more likely, a basal position that approximates the euprimate morphotype. Certain features of the basicranium of "Hesperolemur" actius, described by Gunnell ([1995] Am. J. Phys. Anthropol. 98:447-470) as being unlike that of any other adapiform, were either misinterpreted or are apparently no longer present in the holotype. Reassessment of these and other features indicates that in fact "H." actius differs little from Cantius and should not be separated from the latter at the genus level, although on dental grounds the species appears to be distinct (as C. actius).

show abstract

Middle Ear Morphology of Lemur variegatus

Cited by 35 publications

References 4 publications

Cranial arterial patterns of the alpaca (Camelidae:Vicugna pacos)

Cranial arterial patterns of the alpaca (Camelidae:Vicugna pacos)

Cranial morphology and adaptations in Eocene Adapidae. II. The Cambridge skull of Adapis parisiensis

Skull of early EoceneCantius abditus (primates: Adapiformes) and its phylogenetic implications, with a reevaluation of ?Hesperolemur?actius

Contact Info

Product

Resources

About