title: Membranous Support for Eyes of Strepsirrhine Primates and Fruit Bats.
abstract: Living primates have relatively large eyes and support orbital tissues with a postorbital bar (POB) and/or septum. Some mammals with large eyes lack a POB, and presumably rely on soft tissues. Here, we examined the orbits of four species of strepsirrhine primates (Galagidae, Cheirogaleidae) and three species of fruit bats (Pteropodidae). Microdissection and light microscopy were employed to identify support structures of the orbit. In bats and primates, there are two layers of fascial sheets that border the eye laterally. The outer membrane is the most superficial layer of deep fascia, and has connections to the POB in primates. In fruit bats, which lacked a POB or analogous ligament, the deep fascia is reinforced by transverse ligaments. Bats and primates have a deeper membrane supporting the eye, identified as the periorbita (PA) based on the presence of elastic fibers and smooth muscle. The PA merges with periostea deep within the orbit, but has no periosteal attachment to the POB of primates. These findings demonstrate that relatively big eyes can be supported primarily with fibrous connective tissues as well as the PA, in absence of a POB or ligament. The well-developed smooth muscle component within the PA of fruit bats likely helps to protrude the eye, maintaining a more convergent eye orientation, with greater overlap of the visual fields. The possibility should be considered that early euprimates, and even stem primates that may have lacked a POB, also had more convergent eyes than indicated by osseous measurements of orbital orientation. Anat Rec, 299:1690-1703, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania, 16057.
authors.forename: Brianna M
authors.initials: BM
authors.lastname: Harvey
authors.affiliation: Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky.
authors.forename: Kunwar P
authors.initials: KP
authors.lastname: Bhatnagar
authors.affiliation: Physical Sciences Department, Kingsborough Community College, New York.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Schenck
authors.affiliation: Department of Anthropology and Archaeology, Brooklyn College, CUNY, Brooklyn, New York.
authors.forename: Alfred L
authors.initials: AL
authors.lastname: Rosenberger
authors.affiliation: Department of Biology, Slippery Rock University, Slippery Rock, Pennsylvania.
authors.forename: Susan J
authors.initials: SJ
authors.lastname: Rehorek
authors.affiliation: Department of Physical Therapy, Duquesne University, Pittsburgh, Pennsylvania.|Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Anne M
authors.initials: AM
authors.lastname: Burrows
authors.affiliation: Department of Anthropology, University of Florida, Gainesville, Florida.
authors.forename: Valerie B
authors.initials: VB
authors.lastname: DeLeon
authors.affiliation: School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania, 16057.|Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania.
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Smith
mesh_terms: D000818:Animals; D002685:Chiroptera / Q000033:anatomy & histology* / Q000502:physiology; D003238:Connective Tissue / Q000033:anatomy & histology* / Q000502:physiology; D005123:Eye / Q000033:anatomy & histology*; D009915:Orbit / Q000033:anatomy & histology* / Q000502:physiology; D011443:Strepsirhini / Q000033:anatomy & histology* / Q000502:physiology
keywords: Strepsirrhini; eye; orbital convergence; zygoma