radiolaria - rads_cenozoic - Androcyclas gamphonycha radiolaria - rads_cenozoic - Androcyclas gamphonycha

Androcyclas gamphonycha


Classification: rads_cenozoic -> Pterocorythidae -> Pterocorythidae inc sed -> Androcyclas -> Androcyclas gamphonycha
Sister taxa: A. gamphonycha, A. sp.

Taxonomy

Citation: Androcyclas gamphonycha (Joergensen) Joergensen 1905
taxonomic rank: species
Basionym: Pterocorys gamphonycha Jørgensen 1905
Synonyms:
1900 Pterocorys gamphonyxos - Jørgensen p. 86, not figured
1905 Androcyclas gamphonycha - Jørgensen pl. 17, figs. 92-93
1914 Androcyclas gamphonycha - Schröder figs. 95-97
1965 Androcyclas gamphonycha - Hays p. 178; pl. 3, fig. 2
1971 Lamprocyclas gamphonycha - Petrushevskaya pl. 117, figs. 1-3
1976 Androcyclas gamphonycha - Bjørklund pl. 10, figs. 2-6
1979 Androcyclas gamphonycha - Nigrini and Moore pl. 25, fig. 3
1988 Lamprocyclas gamphonychai - Anderson et al. textfig. 1; pl. 1, fig. 6; pl. 2, fig. 6; pl. 4, figs. 1-4
1995 Androcyclas gamphonycha - Schröder-Ritzrau pl. 5, fig. 11
Taxonomic discussion: (Jørgensen) 1899 p 86 as Pterocorys; Jørgensen 1905 p 139 pl 18 figs 92-97; Hays 1965 p 178 pl 3 fig 2

Catalog entries: Pterocorys gamphonyxos

Original description: Cephalis wie an der vorhergehenden Art und Theocalyptra amblycephalis kurz cylindrisch, unten mit eineim wenig erweiterten querrectangulären Halstheile. Poren dickwandig, ungleich gross,
klein, rundlich. Oben an der einen Seite ein sehr kräftiges breites dreischneidiges Apicalhorn, fast zweimal so lang wie der Cephalis, an der anderen Seite ein ähnliches, aber viel kleineres Horn, das nur 1/4 so lang ist, auch gewöhnlich fehlt. Thorax kurz, breit conisch glockenförmig, mit grösseren, ziemlich dickwandigen Poren, die im unteren Theile grösser und mehr eckig werden. Abdomen kurz und weit glockenförmig mit sehr ungleichen und unregelmässigen Poren, die gegen den unteren Saum grösser und mehr dünnwandig werden. Der Mündungssaum uneben, von einer unvollständigen Reihe grosser Poren, deren unteren Wände an vielen Stellen weggefallen sind, gebildet. (Dieses Exemplar daher wohl noch jung). Das Abdomen ist etwas unterhalb der Mitte mit starken, etwas gekrümmten, eckigen Nebenstacheln versehen, die etwa so lang wie die Breite des Cephalis sind. Unter diesen Stacheln sieht man an den meisten Porenecken ganz kurze ähnliche Stacheln oder pyramidale Erhebungen (die wahrscheinlich später zu ähnlichen Nebenstacheln wie die höher gestellten auswachsen).

Selten: Febr., Mai-Juni, Novbr.-Decbr.
Remarks on original description: [Jorgensen took samples at periodic intervals each month from Jan. 1898 to Dec. 1989. Also included were a few samples from Oct - Dec. 1897. We include here all listed occurrences of this species. der vorhergehenden Art" refers to P. theoconus Jorgensen, 1900.]

Description


Published descriptions


Jørgensen 1905 - Pterocorys gamphonyxos

The region of the neck is very peculiar, not forming any distinct stricture between the cephalis and thorax, but a zone where these two joints gradually pass into each other. This region appears on the dorsal side to lie between two pair of branches from the apical spine, D, namely two dorsal, lateral spines below (corresponding to those in the genus Amphimelissa) and the primary, lateral arches above. These dorsal, lateral spines (from the base of the spine A and the spine D) lie near the hind wall of the cephalis. The lower part of the apical spine, D, is here a columella in the region of the neck, but lying near the cephalic wall. The length of the abdomen varies considerably, probably according to age; this is also the case with the number of byspines. It is not unusual to find comparatively well developed forms which are apparently almost or entirely without the characteristic byspines, but which in other respects diverge so little from the typical forms that they can scarcely be considered to belong to any other species. Therefore I now think that Pterocorys theoconus must be looked upon as a form of this species. The other, very short tophorn is very rarely seen distinctly and is probably a more or less accidental formation. Sometimes strong siliceous edgings are developed on the upper part of the cephalis, and these may be protruding and in certain positions look like a very broad, short spine. According to my experience no limit either can be drawn between Pterocorys gamphonyxos and P. amblycephalis. The younger forms seem to answer best to the latter, which is in appearance so different to P. gamphonyxos that it is generally easy to keep them distinct. (This is done in the tables). The principal difference is that P. amblycephalis has a cephalis which is at the upper part abruptly cut off and, at the very top, often open. This opening is probably closed later on. The tophorn is generally shorter and more weakly developed and the abdomen short and broad, without distinct byspines, all characteristics which may be explained by supposing that P. amblycephalis is the younger stage of development. On individuals which it seemed more correct to refer to P. amblycephalis than to P. gamphonyxos, I have also occasionally seen short and broad byspines in conjunction with a better development of the abdomen. On the best developed specimens of A. gamphonycha, the abdomen is again narrowed below, the strongest set of spines being on that part which is broadest. The byspines are only slightly bent. Frequent, in Tranødybet 6/4-1899, 0-630 m., numerous, otherwise rather sparse and generally only in deep water.

Distribution: On the west coast of Norway, in deep water, rare. Off the coast of Finmark 5/3-1901, in a surface sample (S/S Michael Sars cfr. Gran, 1902, p. 154). Perhaps a temperate oceanic form.


Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source: Lazarus et al. 2015 - "R age group"
First occurrence (base): within Quaternary Period (0.00-2.59Ma, base in Gelasian stage). Data source: Lazarus et al. 2015 - "R age group"

Plot of occurrence data:

References:

Anderson, O. R., Hays, J. D. & Gross, M. (1988). An ontogenetic analysis of changes in morphology during phylogeny of some Lamprocyrtis spp. from deep sea sediments. Micropaleontology. 34(1): 41-51. gs

Bjørklund, K. R. (1976). Radiolaria from the Norwegian Sea, Leg 38 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project. 38: 1101-1168. gs

Hays, J. D. (1965). Radiolaria and late Tertiary and Quaternary history of AntarcticSeas. American Geophysical Union, Antarctic Research Series 5, Llano, G. A.. 125-184. gs

Jørgensen, E (1900). Protophyten und Protozoen im Plankton aus der norwegischen Westkuste. Bergens Museums Aarbog. 1899(6): 51-95. gs O

Jørgensen, E (1905). The protist plankton and diatoms in bottom samples: Radiolaria. In, Nordgaard (ed.) Hydrographical and biological investigation in Norwegian Fjord. 49-151. gs O

Nigrini, C. A. & Moore, T. C. Jr. (1979). A guide to modern Radiolaria. Cushman Foundation for Foraminiferal Research, Special Publication. 16: 1-260. gs O

Schröder, O (1914). Die nordischen Nassellarian. In, Brandt, K. & Apstein, C. (eds) Nordisches Plankton. Lipsius und Tischer, Kiel and Leipzig 67-146. gs O

Schröder-Ritzrau, A (1995). Aktuopalaontologische Untersuchung zu Verbreitung und VertikalfluB von Radiolarien sowie ihre raurnliche und zeitliche Entwicklung im Europaischen Nordmeer. Berichte Sondeiforschungsbereich Univ Kiel. 313(52): 1-99. gs

Missing or ambiguous references: Petrushevskaya 1971;


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Androcyclas gamphonycha compiled by the radiolaria@mikrotax project team viewed: 17-6-2024

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