Bekoma campechensis


Classification: rads_cenozoic -> Theoperidae -> Bekomidae -> Bekoma -> Bekoma campechensis
Sister taxa: B. bidartensis, B. campechensis, B. demissa, B. divaricata, B. helenae, B. oliva, B. sp.

Taxonomy

Citation: Bekoma campechensis Foreman 1973
Rank: species
Basionym: Bekoma campechensis
Taxonomic discussion: Foreman 1973 p 432 pl 3 fig 24 pl 10 figs 1-2 p 444 fig 4; Blome 1992 (ODP 122 SR) p 644 pl 4 figs 15&17 (synonymy)

Catalog entries: Bekoma campechensis

Original description: Shell of two segments with three feet joined by branches which form a triangular ring. Cephalis dome-shaped to rectangular in outline, bearing a conical or cylindrical apical horn and vertical horns. Apex of cephalis flattened, causing the angular appearance when viewed dorsally or ventrally. Cephalis and proximal thorax poreless with a thick hyaline wall, surface roughened with minute irregular papillae, occasionally with tiny spines or nodes apically. Collar stricture not defined externally as contour of cephalis merges with that of thorax. Internally six collar pores, the vertical spine rising very sharply so that the cervical pores tend to be almost in a vertical plane. Thorax proximally narrow, necklike, distally expanded, tending to have straight sides. Expanded portion with pores generally subcircular and subregular in size and arrangement, and surface roughened with small, generally pointed nodes. Fragments of thin lamellar lattice extend below the wide, open aperture. Three sturdy, proximally ridged, straight, divergent feet depend from the shell immediately above the smooth apertural rim. They are joined distally by a triangular ring which is formed by a single inward directed branch of each foot bifurcating and curving slightly downward to join the similar branch of each adjacent foot.

(Based on 20 specimens) Length of cephalis and thorax together 100-140 µ (majority 120-135 µ); width of thorax 105-130 µ; length of feet 65-300 µ (generally 120-200 µ). Distinguishing characters (rw): B. campechensis differs from B. divaricata as described under that species. Phylogeny (rw): The origin of this species is not known, but it is the ancestor of Bekoma bidartensis. It evolved into Bekoma bidartensis in the late Paleocene

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Paleogene Period (23.03-66.04Ma, top in Chattian stage). Data source: Lazarus et al. 2015 - "P age group"
First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Lazarus et al. 2015 - "P age group"

Plot of occurrence data:

References:

Blome, C. D. (1992). Radiolarians from Leg 122, Exmouth and Wombat Plateaus, Indian Ocean C.D. Blome. Proceedings of the Ocean Drilling Program, Scientific Results. 122: 633-652. gs

Foreman, H. P. (1973a). Radiolaria of Leg 10 with systematics and ranges for the families Amphipyndacidae, Artostrobiidae, and Theoperidae. Initial Reports of the Deep Sea Drilling Project. 10: 407-474. gs


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Bekoma campechensis compiled by the radiolaria@mikrotax project team viewed: 22-10-2020

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Short stable page link: http://mikrotax.org/radiolaria/index.php?id=203308 Go to Archive.is to create a permanent copy of this page - citation notes



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