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May 2001
Triacartus? n.sp. A.

ODP Site 1121, eastern flanks of Campbell Plateau, Late Paleocene, 1121B-8-5, 120-122 cm

Genus TRIACARTUS Haeckel
Triacartus Haeckel 1881, p. 437. Type species Stichopilium cortina Haeckel, 1887, p. 1437. (SD Campbell, 1954, p. D136)
Stichopilium Haeckel 1881, p. 438; 1887, 1436 (obj. syn.)

Triacartus? sp. A

Description: Narrowly conical to cylindrical test of three to four segments. Segmentation indistinct. Spheroidal cephalis bears two main horns and one to three accessory spines. Short trapezoidal thorax bears three short lateral spines. When it forms the last segment, abdomen is cylindrical, otherwise barrel-shaped. Fourth segment cylindrical or barrel-shaped. Basal termination ragged. Circular pores gradually increase in size from cephalis to final segment.

Remarks: Bears little resemblance to any other known species.

Chris Hollis 2001/04/30

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Your posted "Mystery Rad May 2001" has been given little attention and no response by your colleagues, myself included. Here a few comments:

I will start with your December 2000 Mystery Rad. You suggested the genus Aspis?, while Dumitrica (1973) DSDP Leg 21, plate 3 Figs 2-4, suggested Ceratocyrtis for the same genus.

In your May 2001 Mystery Rad you pick the Genus Triacartus? As far as I am concerned the general body-structure of your two Mysrery-Rad species are the same except for the exterior cephalic spine ornamentation. If your Triacartus? n.sp. A. is modified so that the cephalic spines do swell and even merge, what is then the difference between your two Mystery Rads? Just the exterior cephalic ornamentation, as I see it. Do you have any good arguments why to put them in different genera? I think that your two mystery rads belongs to the same genus. I have no experience through working with your fauna, or similar faunas, but I only have a feeling that there is no reason to use more than one genus. Which name you prefer is up to you I guess.Anyway, how do your species range through time? Do they co-occur in all you section? Do they overlap slightly? Could the one evolve from the other?

Kjell R. Bjørklund (2001/09/04)

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