| Home> Cenozoic> Holocene (Recent)> Gulf of California>
 

List species

Eucyrtidium anomalum Haeckel, 1861

Description - Add description

Benson, 1966, p. 496-498; pl. 34, figs. 4-5:

Eucyrtidium anomalum Haeckel

Lithocampe anomala Haeckel, 1861b, Akad. Berlin, Monatsb. (1860), p.839.
Eucyrtidium anomalum Haeckel, 1862, Die Radiolarien, pp. 323-324, Pl. 7, figs. 11-13.

Cephalis spherical, with rough surface and very small circular pores, in many specimens infilled with silica; cephalis slightly depressed within the thorax and separated from this joint by a distinct change in contour and generally by an indistinct constriction. Thorax long, broad distally, truncate-conical to slightly campanulate, with smooth surface and small, equal, hexagonal to subcircular pores, hexagonally arranged in longitudinal rows which are generally continuous with similar rows on the abdominal joints. Abdominal joints smooth, about one-half to one-third the length of the thorax, approximately of equal length, generally three in number, with pores the same as those of the thorax; joints separated from one another by regular, continuous, circular, internal septal rings but not by distinct annular constrictions; distal septal ring or rings irregular, discontinuous in a few specimens. First abdominal joint separated from thorax by a septal ring but generally not by a distinct annular stricture. Broadest joint of the test generally the first abdominal joint; distal joints with sides tapering inward slightly, the last joint nearly cylindrical but with its distal portion curved inward; no hyaline peristorne, terminal or subterminal spines, or latticed tubular mouth observed. Apical bar an internal columella in the dorsal portion of the cephalic cavity, prolonged as a straight, vertical, three-bladed, eccentric apical spine or horn. Vertical spine short, thin, inconspicuous. Collar ring distinct, heavy, circular, with four small, circular collar pores separated by heavy vertical, median and primary lateral bars. Thoracic ribs corresponding to the dorsal and primary lateral bars terminate in the wall of the thorax above its base; they vary from indistinct ribs coincident with slight furrows in the thoracic wall to raised ribs coincident with angular shoulder-like swellings of the thoracic wall that resemble latticed wings; in other tests the ribs are raised only slightly above the thoracic surface and are more like the wing-like ribs of Eusyringium siphonostoma.

Measurements; based on 10 specimens from stations 27, 34, and 46: maximum length of test 129-160 Ám, maximum breadth 81-96 Ám; length of cephalis 18-25 Ám, of thorax 53-65 Ám, of abdominal joints 22-39 Ám; breadth of cephalis 22-25 Ám, of thorax 77-92 Ám; length of apical spine or horn 2-27 Ám, of vertical spine 2-5 Ám.

Remarks. This species differs from incompletely developed specimens of Eusyringium siphonostoma in its greater breadth relative to length, the presence of a longer thorax and generally only three abdominal joints, in the pronounced shoulder-like thoracic swellings in many tests, and in a nearly hyaline cephalis with a distinct separation from the thorax. This species agrees in all details with Eucyrtidium anomalum Haeckel from the Mediterranean Sea.

Distribution. This species is very rare but nearly cosmopolitan in the Gulf. It is present as far north as station 184 but is absent north of this station as well as at stations 90, 91, 95, and 130. Its low relative frequency is about the same throughout the Gulf; therefore, analysis of its control by upwelling cannot be determined. Its presence in the northern Gulf indicates some degree of tolerance for waters of higher than average temperature and salinity, but its absence at most of the marginal stations and all of the northernmost shelf localities indicates its preference for offshore, more nearly oceanic waters. It is apparently a tropical species. Its only other known occurrence is in the Mediterranean Sea.
Benson 1966
Benson, 1983, p. 503:

Eucyrtidium(?) anomalum

Remarks. This species is placed provisionally in the genus Eucyrtidium, although I observed no vertical tube on the cephalis. This feature is characteristic of Eucyrtidium infundibulum, E. hexagonatum, and E.(?) hexastichum (Benson, 1966, p. 505, text-fig. 26). Further study of Eucyrtidium and Eucyrtidium-like species seems warranted because of Dumitricaĺs (1972, p. 838) rationale for placing E.(?) anomalum in the genus Stichopterygium. See also the renmarks under E.(?) hexastichum.
Benson 1983


Description

 

Images

 

Synonyms

 

References

 

Distribution

 

Discussion / Comments

 

Web links