haemal arch


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  • noun

Synonyms for haemal arch

a structure arising ventrally from a vertebral centrum and enclosing the caudal blood vessels

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maximus in sharing the following attributes: centrum nearly oval in axial view; diagonal lamellae absent in large trunk vertebrae and present in much small caudal centra; intermedialia weakly calcified with well-developed concentric lamellae; basidorsal and basiventral insertions for the neural and haemal arch cartilages well developed with moderately calcified wedge faces; small tubes radiate from the centrum focus (Wintner and Cliff, 1999), passing through concentric lamellae and extend to the margin of the centrum; primary double cone angle, measured from the focus to the anterior or posterior margin of the corpus calcareum, is high; length of centrum much greater than other lamniforms.
Materials examined listed in Appendix I) Birdsong (1975) first proposed the tribe Gobiosomatini (see Smith & Baldwin (1999)) for discussion on spelling of tribe name) as a monophyletic assemblage to include 19 genera of New World gobiids based on the presence of the following characters: (1) vertebral count of 11 precaudal, 16-17 caudal; (2) first dorsal pterygiophore pattern of 3(221110); (3) scapula unossified; and (4) first 2 anal pterygiophores inserted anterior to the first haemal arch.
This group was phenetically associated with the Gobiosoma group on the basis of a dorsal pterygiophore pattern of 3(221110), vertebral count of 11+16, one epural and two anal pterygiophores anterior to the first haemal arch.
We place Antilligobius nikkiae within the Microgobius group of the Gobiosomatini based on the presence of the following characters: vertebrae 11 +16; dorsal pterygiophore formula 3(221110); anal pterygiophores anterior to the first haemal arch 2; hypurals 1-2 and 3-4 not fused; dorsal papillae row n elongate, uniting across dorsum; caudal fin lanceolate; body laterally compressed; metapterygoid process not overlapping the quadrate; and modified basicaudal scales absent.
The modified haemal arch and its elongate parapophyses, "rib-like" in appearance in lateral view, where parapophyses join ventrally to form the haemal arch, is easily confused with pleural ribs in radiographs.
Vertebral transition a modified Type A, with the tenth abdominal and first caudal vertebrae (only) with a small basal haemal canal, the main haemal arch of the first caudal vertebra expanded, that of the second about half the size of the first, remaining caudal haemal arches normal; swimbladder terminates at the haemal canal of second caudal vertebra.
Similarly, the spine of the first haemal arch should be inserted between the 3rd and 4th anal pterygiophores (Nemeth 1994).