Tags

Type your tag names separated by a space and hit enter

Cranial and spinal nerve organization in amphioxus and lampreys: evidence for an ancestral craniate pattern.
Acta Anat (Basel). 1993; 148(2-3):96-109.AA

Abstract

The spinal nerves in amphioxus are compared with the spinal and cranial nerves in lampreys. The dorsal spinal roots in amphioxus are similar to the mixed sensory and motor dorsal roots of many cranial nerves in lampreys but not to the purely sensory dorsal spinal roots in lampreys and gnathostomes. Likewise, cranial nerves V, VII, IX and X in lampreys, and all spinal nerves in amphioxus, lack a separate ventral motor root which is a constant feature of all spinal motor roots in lampreys and other vertebrates. Based on these similarities and differences, it is proposed that cranial and spinal nerves in craniates are independently derived serial homologs of elements of an amphioxus-like ancestral pattern. Further evolution involved the addition of neural crest-derived ganglia to most cranial and all spinal nerves, and the addition of placodally derived ganglia to many cranial nerves. The possible homology of ocular motor nerves is discussed but cannot be resolved owing to the absence of these nerves in hagfishes, which are the only relevant outgroup.

Authors+Show Affiliations

Department of Biomedical Sciences, Creighton University, Omaha, NE 68178.No affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, U.S. Gov't, P.H.S.
Review

Language

eng

PubMed ID

8109201

Citation

Fritzsch, B, and R G. Northcutt. "Cranial and Spinal Nerve Organization in Amphioxus and Lampreys: Evidence for an Ancestral Craniate Pattern." Acta Anatomica, vol. 148, no. 2-3, 1993, pp. 96-109.
Fritzsch B, Northcutt RG. Cranial and spinal nerve organization in amphioxus and lampreys: evidence for an ancestral craniate pattern. Acta Anat (Basel). 1993;148(2-3):96-109.
Fritzsch, B., & Northcutt, R. G. (1993). Cranial and spinal nerve organization in amphioxus and lampreys: evidence for an ancestral craniate pattern. Acta Anatomica, 148(2-3), 96-109.
Fritzsch B, Northcutt RG. Cranial and Spinal Nerve Organization in Amphioxus and Lampreys: Evidence for an Ancestral Craniate Pattern. Acta Anat (Basel). 1993;148(2-3):96-109. PubMed PMID: 8109201.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cranial and spinal nerve organization in amphioxus and lampreys: evidence for an ancestral craniate pattern. AU - Fritzsch,B, AU - Northcutt,R G, PY - 1993/1/1/pubmed PY - 1993/1/1/medline PY - 1993/1/1/entrez SP - 96 EP - 109 JF - Acta anatomica JO - Acta Anat (Basel) VL - 148 IS - 2-3 N2 - The spinal nerves in amphioxus are compared with the spinal and cranial nerves in lampreys. The dorsal spinal roots in amphioxus are similar to the mixed sensory and motor dorsal roots of many cranial nerves in lampreys but not to the purely sensory dorsal spinal roots in lampreys and gnathostomes. Likewise, cranial nerves V, VII, IX and X in lampreys, and all spinal nerves in amphioxus, lack a separate ventral motor root which is a constant feature of all spinal motor roots in lampreys and other vertebrates. Based on these similarities and differences, it is proposed that cranial and spinal nerves in craniates are independently derived serial homologs of elements of an amphioxus-like ancestral pattern. Further evolution involved the addition of neural crest-derived ganglia to most cranial and all spinal nerves, and the addition of placodally derived ganglia to many cranial nerves. The possible homology of ocular motor nerves is discussed but cannot be resolved owing to the absence of these nerves in hagfishes, which are the only relevant outgroup. SN - 0001-5180 UR - https://www.unboundmedicine.com/medline/citation/8109201/Cranial_and_spinal_nerve_organization_in_amphioxus_and_lampreys:_evidence_for_an_ancestral_craniate_pattern_ DB - PRIME DP - Unbound Medicine ER -