CATALOG OF ORIGINAL DESCRIPTIONS: Sethocyrtis austellus Sanfilippo & Blome 2001

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.


Higher levels: rads_cat -> S -> Sethocyrtis -> Sethocyrtis austellus
Other pages this level: S. agamemnonis, S. austellus, S. bacaformis, S. capitatus, S. capitatus juvenus, S. chrysallis, S. colettii, S. crassus, S. diomedis, S. elegans, S. expositus, S. japonica, S. laguncularis, S. menelai, S. mica, S. minimus, S. mitrus> >>

Sethocyrtis austellus

Citation: Sethocyrtis austellus Sanfilippo & Blome 2001
Rank: species
Type specimens: fig. 6h, i
Type repository: Holotype (Fig. 6h) from 171B-1051A-24X-5, 40-42 cm, in the middle Eocene interval that is equivalent to the low-latitude Podocyrtis (Podocyrtoges) ampla Zone (equivalent to calcareous nannofossil Zone CP13b).
Described on page(s) : p.206
Family (traditional): Pterocorythidae
Family (modern): Pterocorythidae

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Current identification:


Original Description
This form is similar to Sethocyrtis chrysallis n. sp. in most of its characters except for being three-segmented rather than two-segmented. The cephalis is poreless or with a few scattered pores and bears a slender, sometimes roughened, conical horn of variable length. Some specimens have a small pore at the base of the horn. The thoracic pores are small, closely packed, circular, uniform in size and arrangement in longitudinal rows. Collar and lumbar strictures distinct. The abdomen is somewhat narrower than the thorax, with pores that are 1.5-2 times larger than the thoracic ones, quincuncially arranged. Abdomen terminates in a differentiated hyaline peristome.

Measurements based on 20 specimens from 171B-1051A-24X-5, -25X-2, -25X-5, and -26X-2. Total length (excluding horn) 140-200 µm; length of cephalothorax 90-120 µm; length of abdomen 35-100 µm; length of horn 20-65 µm; breadth of thorax 75-100 µm; breadth of abdomen 75-100 µm. There are commonly 15 pores on half the circumference on the thorax, and 8-11 pores on half the circumference of the abdomen. Distinguishing characters (rw): It is distinguished from its descendant Sethocyrtis chrysallis n. sp. in having three rather than two segments, from the Antarctic lophocyrtid taxa Aphetocyrtis rossi and A. gnomabax in possessing a horn, a longer more porous thorax, and in a constricting abdominal peristome, and from Lophocyrtis (Lophocyrtis ?) semipolita by its longer thorax and shorter abdomen with a differentiated termination. The length of the abdomen and the development of the peristome are somewhat variable. Phylogeny (rw): Origin unknown; gave rise to S. chrysallis n.sp. as described under that species.

Etymology: The name is derived from the Latin noun austellus, meaning gentle south wind.

References:

Sanfilippo, A. & Blome, C. D. (2001). Biostratigraphic implications of mid-latitude Palaeocene-Eocene radiolarian faunas from Hole 1051A, ODP Leg 171B, Blake Nose, western North Atlantic. Geological Society of London, Special Publications. 183: 185-224. gs


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Sethocyrtis austellus compiled by the radiolaria@mikrotax project team viewed: 18-4-2021

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