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Tholospyris baconiana baconiana Goll, 1972

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Benson, 1966, p. 336-338; pl. 23, figs. 10-12:

Tricolospyris kantiana Haeckel

Tricolospyris kantiana Haeckel, 1887, Challenger Rept., Zool.,vol. 18, p. 1098, Pl. 88, fig. 10.

Fully developed tests with three smooth joints--a middle joint with sagittal constriction representing the bilocular cephalis, and an apical and basal cupola. Two to three, large, circular to subcircular or polygonal pairs of pores separated by the sagittal ring on both the dorsal and ventral faces of the cephalis; remaining pores of cephalis smaller, unequal, circular to polygonal, slightly larger or about the same size as those of the cupolas. Shape of cephalis variable from nearly ellipsoidal or nut-shaped to one with irregular lateral lobes. Shape of cupolas variable from dome-shaped to nearly cylindrical. Most tests incompletely developed, consisting of portions of all three joints. In a few specimens the cupolas are not separated by constrictions from the cephalis, and the test is discoidal, nearly circular to elliptical in outline. Sagittal ring three-bladed with one blade extending inward in the sagittal plane and two extending laterally outward; ring asymmetrical, with a short, cylindrical median bar at its base. Four collar pores present, the cardinal and cervical pores, with shape and size similar to those of most of the other triospyrid species. The apical spine extends from the vertical, straight apical bar of the sagittal ring; in fully developed forms it bifurcates distally to form a part of the lattice of the apical cupola. A short, blade-like vertical spine is present. Basal cupola consists of a lattice developed from short, downward divergent spines originating from the collar ring; these include the dorsal spine, in most specimens spines originating from the distal ends of the primary lateral bars, a pair of spines each originating from the ventro-lateral corners of the collar ring, in a few specimens spines originating from the distal terminations of the secondary lateral bars, and in most specimens a few spines located between the above; the spines do not form ribs in the wall of the basal cupola but instead branch distally to form a portion of its lattice. The primary and secondary lateral bars extend as and are collinear with short horizontal spines in a few specimens.

Measurements; based on 30 specimens from stations 71, 92, 93, 106, 115, and 133: sagittal height of cephalis 46-63 µm, maximum breadth 76-168 µm; maximum height of shell (both cupolas) 84-169 µm.

Remarks. The presence of well-developed collar pores and the generally bilocular nature of the middle joint places this species within the Superfamily Triospyridicae. The three joints are not easily distinguishable in several specimens; in most specimens the cephalis and apical and basal cupolas are incompletely developed. A few specimens, however are identical with Haeckel's illustration (1887, Pl. 88, fig. 10) of Trico1ospyris kantiana.
This species differs from the Gulf species of the Superfamily Acanthodesmiacea in the lack of apical, zygomatic, or frontal rings, the presence of well-developed collar pores,. and a bilocular cephalis generally with a sagittal constriction. Incompletely developed forms are recognized by the 2-3 pairs of large pores on either side of the sagittal ring on both the dorsal and ventral faces of the cephalis.

Distribution. This species is very rare in the Gulf but is cosmopolitan in that it occurs as far north as station 192. It is absent at stations 27, 64, 81, 91, 92, 130, 151, 191, 194, and all those to the north. Its absence at marginal stations indicates its preference for offshore or more nearly oceanic waters. It does not appear to be associated with areas of upwelling.
Haeckel (1887, p. 1098) reported this species from the western tropical Pacific at “Challenger” station 225. It is apparently a tropical species because it has not been reported from high latitudes.
Benson 1966











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