Ontogeny of the Orbital Glands and Their Environs in the Pantropical Spotted Dolphin (Stenella attenuata: Delphinidae).

Title

Ontogeny of the Orbital Glands and Their Environs in the Pantropical Spotted Dolphin (Stenella attenuata: Delphinidae).

Creator

Rehorek Susan J; Hillenius Willem J; Lovano Denise M; Thewissen J G M

Publisher

Anatomical record (Hoboken, N.J. : 2007)

Date

2018
2018-01

Description

The nasolacrimal duct (NLD) connects the orbital (often associated with the Deep Anterior Orbital gland: DAOG, a.k.a. Harderian gland) and nasal regions in many tetrapods. Adult cetaceans are usually said to lack an NLD, and there is little agreement in the literature concerning the identity of their orbital glands, which may reflect conflicting definitions rather than taxonomic variation. In this study, we examined an embryological series of the pantropical spotted dolphin (Stenella attenuata), and report numerous divergences from other tetrapods. Underdeveloped eyelids and a few ventral orbital glands are present by late Stage (S) 17. By S 19, circumorbital conjunctival glands are present. In S 20, these conjunctival glands have proliferated, eyelids (and scattered palpebral glands) have formed, and a duct similar to the NLD has appeared. Subsequently, both the palpebral glands and the NLD are progressively reduced by S 22, even as the conjunctival glands exhibit regional growth. In most tetrapods examined, the ontogeny of the NLD follows a series of three stages: Inception of NLD, Connection of orbit and nasal cavity by the NLD and Ossification (i.e., formation of the bony canal surrounding the NLD, emerging into the orbit via the lacrimal foramen in the lacrimal bone). In contrast, the dolphin NLD originates at the same time as the lacrimal bone, and a lacrimal foramen fails to develop. The cetacean fossil record shows that a lacrimal foramen was present in the earliest ancestral amphibious, freshwater forms, but was soon lost as the lineage invaded the oceans. Anat Rec, 2017. (c) 2017 Wiley Periodicals, Inc. Anat Rec, 301:77-87, 2018. (c) 2017 Wiley Periodicals, Inc.

Subject

Animals; cetacean; Fossils/anatomy & histology; Harderian Gland/*embryology; Morphogenesis/*physiology; Nasal Cavity/embryology; nasolacrimal duct; Nasolacrimal Duct/*embryology; ontogeny; Orbit/embryology; orbital glands; Stenella/*embryology

Identifier

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

77–87

Issue

1

Volume

301

Citation

Rehorek Susan J; Hillenius Willem J; Lovano Denise M; Thewissen J G M, “Ontogeny of the Orbital Glands and Their Environs in the Pantropical Spotted Dolphin (Stenella attenuata: Delphinidae).,” NEOMED Bibliography Database, accessed April 17, 2021, https://neomed.omeka.net/items/show/2972.

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