radiolaria - rads_cenozoic - Lamprocyrtis nigriniae

Citation: Lamprocyrtis nigriniae (Caulet) Kling 1973

Basionym: Conarachnium nigriniae

Synonyms:
1966 Conarachnium sp. - Benson p. 479-482; pl. 33, figs. 2-3
1968 Conarachnium ? sp. A - Nigrini p. 56; pl. 1, figs. 5a-5b
1971 Conarachnium nigriniae - Caulet p. 3; pl. 3, figs. 1-4; pl. 4, figs. 1-4
1973 Lamprocyrtis haysi - Kling p. 639; pl. 5, figs. 15-16; pl. 15, figs. 1-3
1974 Lamprocyrtis haysi - Renz p. 793; pl. 19, fig. 26
1977 Lamprocyrtis nigriniae [= L. haysi Kling, 1973] - Kling p. 217; pl. 1, fig. 17
1977 Lamprocyrtis haysi - Molina-Cruz p. 337; pl. 6, fig. 9
1979 Lamprocyrtis nigriniae - Nigrini and Moore p. N81-N82; pl. 25, fig. 7
1980 Lamprocyrtis nigriniae - Johnson and Nigrini p. 129; pl. 3, fig. 24
1982 Lamprocyrtis nigriniae - Molina-Cruz p. 996; pl. 4, fig. 4
1983 Lamprocyrtis nigriniae - Benson p. 504
1984 Lamprocyrtis nigriniae - Nishimura and Yamauchi p. 51; pl. 36, figs. 10a-10b
1991 Lamprocyrtis nigriniae - Takahashi p. 127; pl. 43, figs. 17-19
1992 Lamprocyrtis nigriniae - Nigrini and Caulet p. 146, 148; pl. 2, figs. 11-12
1995 Lamprocyclas nigriniae - van de Paverd p. 248-250; pl. 75, fig. 6
1998 Lamprocyrtis nigriniae - Boltovskoy fig. 15.157

From Suzuki Paleotax db:

1971 Conarachnium nigriniae n. sp. Caulet p. 3-4, pl. 3, figs. 1-4, pl. 4, figs. 1-4
1974 Anthocyrtidium nigriniae (Caulet) Caulet p. 239-240, pl. 10, figs. 5-6
1977 Lamprocyrtis nigriniae (Caulet) Kling p. 217, pl. 1, fig. 17
1979 Lamprocyrtis nigriniae (Caulet) Kling p. 309, pl. 2, fig. 26
1979 Lamprocyrtis nigriniae (Caulet) Nigrini & Moore N81-82, pl. 25, fig. 7
1980 Conarachnium nigriniae Caulet Goll p. 436, pl. 3, fig. 10
1980 Lamprocyrtis nigriniae (Caulet) Johnson & Nigrini p. 129, text-fig. 13a, pl. 3, fig. 24
1981 Lamprocyrtis nigriniae (Caulet) Wolfart p. 498, pl. 2, figs. 1, 2
1982 Lamprocyrtis nigriniae (Caulet) Molinap. 996, pl. 4, fig. 4
1984 Lamprocyrtis nigriniae (Caulet) Nishimura & Yamauchi p. 51, pl. 36, fig. 10
1985 Lamprocyrtis nigriniae (Caulet) Boltovskoy & Jankilevich pl. 5, fig. 3
1985 Lamprocyrtis nigriniae (Caulet) Morley p. 411, pl. 6, fig. 1
1985 Lamprocyrtis nigriniae (Caulet) Sanfilippo et al. p. 694-695, figs. 29.1a, 29.1b, 29.1c
1985 Lamprocyrtis sp. cf. nigriniae (Caulet) Sanfilippo et al. fig. 29.7
1988 Lamprocyrtis nigriniae (Caulet) Anderson et al. pl. 1, figs. 4, 5, pl. 3, figs. 2-4
1989 Lamprocyrtis nigriniae (Caulet) Alexandrovich pl. 2, fig. 8
1991 Lamprocyrtis nigriniae (Caulet) Takahashi p. 127, pl. 43, figs. 17-19
1992 Lamprocyrtis nigriniae (Caulet) Nigrini & Caulet pl. 146, 148, pl. 2, figs. 11, 12
1992 Lamprocyrtis nigriniae (Caulet) Sanfilippo & Riedel pl. 4, fig. 9
1995 Lamprocyrtis nigriniae (Caulet) Morley & Nigrini pl. 7, fig. 9
1996 Lamprocyrtis nigriniae (Caulet) Chen & Tan p. 223, pl. 32, ifg. 18, pl. 53, figs. 7, 8
2003 Lamprocyrtis nigriniae (Caulet) Tan & Su p. 199-200, pl. 2, fg. 13; pl. 8, fig. 3; pl. 20, figs. 7, 8

Taxonomic discussion: (Caulet) 1971 p.3 pl.3 figs.1-4,pl.4 figs.1-4 as Conarachnium;Nigrini & Moore 19; Alexandrovich 1989 (ODP 111 SR) p.256 pl.2 fig.8 (synonymy)

Original description: Sethocyrtidae avec un thorax campanuliforme, multiperforé, lisse et largement ouvert. Céphalis cylindrique, trilobé, à pores plus petits, avec une grande corne apicale et une ou plusieurs petites cornes secondaires. Spicule initial polyactine à axobate simple. (Le terme axobate adopté ici est du à J. et M. Cachon, 1972, qui traduisent ainsi l'axial spine - ou axostyle sec. Petrushevskaja - des auteurs écrivant en anglais).
QTLa coque externe, de forme conique, se compose de deux segments. Ces deux segments sont largement perforés, présentent une surface lisse mais ne sont pas séparés par une constriction bien marquée. Le céphalis, cylindrique, est en moyenne cinq fois plus petit que le thorax. Il porte une forte corne apicale droite, aussi longue que lui-même et à trois côtes. Une ou plusieurs petites cornes secondaires peuvent orner son sommet qui est ouvert sur quelques spécimens. A sa surface, se disposent sans ordre apparent de nombreux petits pores arrondis de taille inégale. La crête dorsale et deux sillons très peu prononcés issus du milieu du côté dorsal du céphalis et dirigés ventralement vers le thorax, subdivisent ce dernier en trois lobes peu marqués. Le thorax se distingue du céphalis seulement par un élargissement très net de la coque externe qui reste lisse et très fragile. Son ouverture, très large, ne possède pas de péristome bien différencié, mais est précédée d'une très légère constriction de la coque. Les pores, très nombreux, sont de forme subcirculaire à polygonale. Beaucoup plus larges que les cloisons qui les séparent, ils sont alignés en alternance et leur dimension va en augmentant vers l'ouverture. On en compte en moyenne de S à 8 de l'avant vers l'arrière et de 4 à 6 transversalement. Le squelette interne est développé à partir d'un spicule initial polyactine. Depuis le bâtonnet basal (MB), légèrement incliné du côté ventral, se diversifient sept grandes actines et un petit axobate. Vers la partie ventrale, se dresse l'actine ventrale (V) qui se prolonge à l'extérieur de la paroi du céphalis par une très courte aiguille, puis s'abaissent les deux grandes actines latérales droite et gauche (L1 et L2) qui se poursuivent par un épaississement interne de la paroi du thorax sur au moins un tiers de sa longueur. Au point de jonction du bâtonnet basal et des actines ventro-latérales, prend naissance un petit axobate simple, en forme d'aiguille, souvent rompu près de la base. Du côté dorsal, se dresse vers l'avant, et très légèrement en oblique par rapport au bâtonnet basal, l'actine apicale (A), d'abord libre puis soudée à la paroi du céphalis, se terminant enfin par la puissante corne apicale. Egalement du côté dorsal, s'abaissent vers le thorax les deux petites actines latérales (l1 et l2) qui se prolongent à l'extérieur de la coque par de très fines aiguilles. L'actine dorsale (D) se poursuit, non pas par une aiguille externe, mais par un épaississement interne de la paroi du thorax aussi long que ceux des actines ventro-latérales. Les deux paires d'actines latérales sont reliées par deux épaississements subcirculaîres du thorax qui forment ce que M.G. Petrushevskaja (1968) appelle des \ arches \". Les arches reliant les actines latérales ne sont pas les seules visibles. Les constrictions du céphalis se traduisent aussi par des arches internes, plus prononcées que les précédentes et disposées plus antérieurement (voir fig.1, Pl.4). D'autre part, deux arches prennent naissance au point de jonction de l'actine ventrale et de la paroi du céphalis.

Description

Benson 1966 - Conarachnium nigriniae

Cephalis cylindrical, generally open at the top but closed in a few specimens, with a corona of 1-8 or more spines surrounding the opening, with a straight dorsal face and a pair of dorso-lateral lobes. Apical bar straight, free within the cephalis proximally, a straight dorsal rib in the cephalis distally, extends as and is collinear with a three-bladed apical spine or horn, the two lateral blades of which merge with the dorsal face of the cephalis. Vertical bar extends as a short, thin, conical, vertical spine originating at the base of the ventral face of the cephalis. Cephalis separated from a broad, slightly inflated, conical thorax with irregular outline by a change in contour but not by a distinct stricture. Terminal margin of thorax incomplete, but in one specimen the mouth slightly constricted but its margin incompletely developed. Surface of both joints smooth in a few specimens but generally with a few scattered thorns or short spines. Pores of the cephalis circular, subequal, subregularly arranged, slightly wider than the intervening bars. Pores of the thorax subcircular to polygonal, increase in size distally (from about 4-9 m proximally to 18-20 µm distally), with subregular hexagonal arrangement in longitudinal rows, 7-9 on half the thoracic circumference. Four collar pores present, but in a few specimens a pair of jugular pores are present and are covered by the dorso-lateral lobes. Secondary lateral bars do not extend as spines. Dorsal and primary lateral bars extend as ribs in the thoracic wall for a distance of 2 to 4 thoracic pores; ribs occupy slight furrows in the thorax and generally terminate in short, inconspicuous spines.

Measurements: based on 30 specimens from stations 27, 34, 46, 56, and 106: length of cephalis 25-46 µm, of thorax 76-172 µm; breadth of cephalis 25-32 µm, of thorax 86-138 µm; length of apical born 18-37 µm, of vertical spine 2-6 µm, of coronal spines surrounding the open top of the cephalis 5-12 µm, of dorsal and primary lateral spines 5-12 µm.

Remarks: This species is distinguished by the opening in the upper face of the cephalis, by the broad thorax with irregular outline and incomplete terminal margin, and the absence of terminal or subterminal spines. The basic structure of the cephalis and apical horn, including the dorso-lateral lobes is the same as that of Anthocyrtium oxycephalis , Anthocyrtidium cineraria , and Lamprocyclas maritalis. No reference to this species was found in the literature. The only illustrated species having a cephalis with a straight dorsal face and with its top open and lacking an abdomen is Sethoconus conicus Popofsky (1909, p. 287, Pl. 33, figs. 10, 11).This species differs from the Gulf species in the presence of a latticed apical horn, the lack of a corona of spines surrounding the opening of the cephalis, and in having a smooth surface with small pores separated by wide intervening bars. Campbell (1954, p. D128) indicates that Sethoconus Haeckel (1882, p. 430) is an objective synonym of Conarachnium Haeckel (1882, p. 430) [= Ceratocyrtis Bütschli, 1882a, p. 536].The Gulf species conforms to the definition of Conarachnium Haeckel, but because no specimens were observed with the terminal margin of the thorax completely developed, the complete range of variation of this species could not be determined. For this reason a new name is not proposed for this taxon.

Distribution: This species is cosmopolitan in the Gulf, occurring as far north as stations 191 and 192.It is absent at the marginal stations 90 and 130 and the northern shelf localities including station 194 and those north of it; therefore, it prefers an offshore, more nearly oceanic habitat. It is common at stations 91 (2.4%), 99 (2.4%), 106 (3.2%), 115 (20%), and 151 (2.6%) and rare to nearly common at most of the other stations in the Gulf. Across the Gulf from stations 91 to 99, it has a greater frequency at stations 91 and 99 than at 92 and 93 (1.6%) and 95 (0.2%).It, therefore, responds to upwelling along both the coasts of Baja California (station 91) and the Mexican mainland (station 99) in this region of the Gulf. South of this area its frequency is lower but reaches 1.6% at stations 46 and 56, the latter located within a region of upwelling. It is very rare at station 64 which is in an area of upwelling off the Mexican mainland. Its average frequency in the northern half of the Gulf is much greater than that in the southern half. It is nearly common to common at all stations within the diatomite facies except 191 and 192 where it is very rare; therefore, its distribution in this region is controlled by upwelling. \ From: Benson, 1966, p. 479-482; pl. 33, figs. 2-3:Conarachnium sp.

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"

References:

Alexandrovich, J. M. (1989). Radiolarian biostratigraphy of ODP Leg 111, Site 677, eastern equatorial Pacific, late Miocene through Pleistocene. Proceedings of the Ocean Drilling Program, Scientific Results. 111: 245-262. gs

Benson, R. N. (1966). Recent Radiolaria from the Gulf of California. Thesis, Minnesota University. 1-577. gs

Benson, R. N. (1983). Quaternary radiolarians from the Mouth of the Gulf of California, Deep Sea Drilling Project Leg 65. Initial Reports of the Deep Sea Drilling Project. 65: 491-523. gs

Caulet, J. (1971). Contribution a l'etude de quelques Radiolaires Nassellaires des boues de la Mediterranee et du Pacifique. Cahiers de Micropaléontologie. 10(498): 1-10. gs

Johnson, D. A. & Nigrini, C. A. (1980). Radiolarian biogeography in surface of the western Indian Ocean. Marine Micropaleontology. 5(2): 111-152. gs

Kling, S. A. (1973). Radiolaria from the eastern North Pacific, Deep Sea Drilling Project, Leg 18. Initial Reports of the Deep Sea Drilling Project. 18: 617-671. gs

Kling, S. A. (1977). Local and regional imprints on radiolarian assemblages from California coastal basin sediments. Marine Micropaleontology. 2(2): 207-221. gs

Molina-Cruz, A. (1977). Radiolarian assemblages and their relationship to the oceanography of the subtropical southeastern Pacific. Marine Micropaleontology. 2(4): 315-352. gs

Molina-Cruz, A. (1982). Radiolarians in the Gulf of California: Deep Sea Drilling Project Leg 64. Initial Reports of the Deep Sea Drilling Project. 64: 983-1002. gs

Nigrini, C. A. & Caulet, J. (1992). Late Neogene radiolarian assemblages characteristic of Indo-Pacific areas of upwelling. Micropaleontology. 38(2): 139-164. gs

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

Nigrini, C. A. (1968). Radiolaria from eastern tropical Pacific sediments. Micropaleontology. 14(1): 51-63. gs

Nishimura, A. & Yamauchi, M. (1984). Radiolarians from the Nankai Trough in the northwest Pacific. News of Osaka Micropaleontologists, Special Volume. 6: 1-148. gs O

Renz, G. W. (1974). Radiolaria from Leg 27 of the DSDP. Initial Reports of the Deep Sea Drilling Project. 27: 769-841. gs O

Takahashi, K. (1991). Radiolaria: Flux, ecology, and Taxonomy in the Pacific and Atlantic. Ocean Biocoenosis Series. 3: 1-301. gs

van de Paverd, P. J. (1995). Recent Polycystine Radiolaria from the Snellius-II Expedition. Thesis, Free University Amsterdam. 1-351. gs

Lamprocyrtis nigriniae

Taxonomy

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

References:

Add Comment

Comments