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Clathrocircus stapedius Haeckel, 1887

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Benson, 1966, p. 307-310; pl. 21, figs. 11-13; pl. 22, figs. 1-2

Clathrocircus stapedius Haeckel

Clathrocircus stapedius Haeckel, 1887, Challenger Rept., Zool., vol. 18, p. 962, Pl. 92, fig. 8.

Majority of tests not fully developed, consisting of the sagittal ring, a collar ring with cardinal and cervical pores, a lattice partially developed from the upper part of the superior bar of the sagittal ring and consisting of two pores on each side of this bar, and an elliptical meridional (frontal) ring, not three-bladed, lying in a plane perpendicular to the sagittal plane and containing the apical bar of the sagittal ring. In most specimens a dorsally extending spine, generally parallel to the sagittal plane, arises from each of four points on the meridional ring, at the upper and lower lateral points of each half of the ring; these spines are branched distally, in one specimen the branches from the upper spine of each half-ring are joined to form an elliptical ring lying in the horizontal plane, resembling a dorsal "handle" (Pl. 21, fig. 13). A few tests were observed, particularly at stations located within the diatomite facies in the Gulf, with bilocular cephalis completely latticed except for the dorsal face; pores of lattice unequal, irregular, relatively large (Pl. 22, figs. 1-2). Sagittal ring approximately D-shaped, with thin bars three-bladed except for a short, horizontal, cylindrical median bar and a thin, cylindrical, ventrally ascending vertical bar. Cardinal pores subtrapezoidal, larger than the subtriangular cervical pores; jugular pores represented by a pair of small circular pores which pierce the broad, planar, proximal portion of the thin, conical dorsal spine and are divided by the dorsal bar that extends as this spine; jugular pores, therefore, technically not a part of the collar ring. Primary lateral bars thin, conical, extend beyond collar ring as spines with sub-distal ascending branches which form a complete or incomplete ring, similar to the frontal ring: the ring joins with the lattice on either side of the superior bar and has secondary spines arising from it and representing an incomplete lattice; this ring generally not distinguishable as a distinct rib in completely latticed tests. A thin, conical vertical spine of variable length extends from and is collinear with vertical bar. Apical spine thin, conical, of variable length, extending from and collinear with the straight, vertical apical bar; a pair of laterally ascending spines arises from its base, their proximal portions representing intervening bars in the upper lattice. Surface of lattice in completely developed tests with a few scattered, thin, conical by-spines.

Measurements; based on 41 specimens from stations 27, 34, 60, 81, 92, 106, and 133: height of sagittal ring 31-46 Ám, breadth 30-38 :m; breadth of meridional ring (lateral axis) 68-102 Ám; breadth of latticed cephalis (1 specimen) 81 Ám; length of apical spine 7-26 Ám, of vertical spine 7-16 Ám, of dorsal spine (portion beyond jugular pores) 9-33 Ám.

Remarks. Haeckel's illustration of C1athrocircus stapedius Haeckel (1887, Pl. 92, fig. 8) does not differ from specimens present in the Gulf. The meridional ring is incomplete, and the vertical spine is not shown, but the four collar pores and the jugular pores are the same as in the Gulf specimens. The presence of the meridional or frontal ring is characteristic of the Superfamily Acanthodesmiacea, but the few tests with a completely latticed bilocular test are similar to the Triospyridicae, another example of the close relationship between these two superfamilies.

Distribution. The frequency of this species increases northward in the Gulf. It is very rare at all of the southern Gulf stations except 93 where it is common; it is absent at stations 64 and 90. Its average frequency in the northern half of the Gulf is rare but greater than in the south, and it is common at two stations, 136 and 192, both located within the diatomite facies; it is absent at stations 130, 194, 203, 206 and 214. Its northward increase may be explained by its response to upwelling. This is indicated by its greater abundance at stations located within the diatomite facies. It apparently does not respond to upwelling in the southern half of the Gulf. Its absence or near absence from marginal stations indicates its preference for a more nearly oceanic habitat.
Haeckel (1887, p. 962) reported this species from the central Pacific at "Challenger" station 271. It has not been reported from high latitudes.
Benson 1966
Benson,1983, p. 501; pl. 7, figs. 5-7

Clathrocircus stapedius

Remarks. Nigriniĺs (1967, pl. 5, fig. 5) illustration of Triceraspyris damaecornis resembles Bensonĺs (1966, pl. 21, fig. 11) Clathrocircus stapedius more closely than it does Dendrospyris damaecornis (Benson, 1966, pl. 22, fig. 2)
Benson 1983
Benson, 1983, p. 502

Dendrospyris damaecornis

Remarks. Benson (1966, p. 308) observed a few tests identified as Clathrocircus stapedius that have a bilocular cephalis completely latticed except for the dorsal face. One of the illustrated specimens (Benson, 1966, pl. 22, fig. 2) resembles the closely related species (Goll, 1968, 1972) Dendrospyris damaecornis as illustrated by Goll (1972, pl. 51, figs. 1-2). The other specimen (Benson, 1966, pl. 22, fig. 1) may belong to either species.
Benson 1983


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