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Dictyophimus killmari
(Renz, 1974)
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Description - Add description
Benson, 1966, p. 414-416; pl. 28, fig. 7:
Pterocorys cf. columba Haeckel
?Pterocorys columba Haeckel, 1887, Challenger Rept., Zool., vol. 18, p.1317, Pl. 71, fig. 2.
Cepha1is cap-shaped, smooth, separated from a short, smooth campanulate thorax by a change in contour, not by a distinct stricture. Abdomen smooth, cylindrical, slightly inflated, or truncate conical, separated from thorax generally by a constriction occupied by an internal septal ring but in a few specimens by a change in contour only; basal margin of abdomen incomplete. Pores of all three joints similar in shape and arrangement--subcircular to subpolygonal, arranged subhexagonally in longitudinal rows; pores of cephalis smaller than those of the thorax and abdomen, those of the thorax slightly larger than those of the abdomen. A thin, conical to three-bladed, straight or gently curved, nearly vertical apical horn originates eccentrically from the top of the cephalis and extends from the apical bar which is a rib occupying a dorsal sagittal furrow in the cephalis. Vertical spine, when present, is generally short. Four collar pores at the base of the cephalis. Dorsal and primary lateral bars extend as indistinct ribs in the thoracic wall. Each of the three long, slender, equal, conical feet extends from a thoracic rib and originates from the broadest part of the thorax above its base; the feet in a few specimens are latticed proximally; in all specimens they are broad and have strong, convex outward curvature proximally; distal portions of feet with slight convex outward curvature, in some specimens their terminal portions subparallel or curved inward.
Measurements; based on 13 specimens from stations 56, 60, 64, 81, and 115: length of cephalis 16-21 µm, of thorax 27-37 µm, of abdomen 15-41 µm; breadth of cephalis 20-26 µm, of thorax 49-55 µm, of abdomen 46-53 µm; length of apical horn 9-26 µm, of vertical spine 0-31 µm (generally 2-8 µm), of feet 27-108 µm.
Remarks. The presence of long, convex outward feet originating from the broadest part of the thorax and the presence of an abdomen are characters that are similar to those of Pterocorys ? sp. as well as to Pterocorys aquila Haeckel and P. hirundo Haeckel. The only illustrated species that resembles the Gulf species is P. columba Haeckel (1887, p. 1317, Pl. 71, fig. 2) from the surface of the North Pacific "Challenger" station 237. This species has shorter and stouter but conical feet and horn and a thorax that is less campanulate, more inflated. The feet diverge downward with little outward convexity, thus are different from the long, slender, convex outward feet of the Gulf species. Whether or not P. columba is an incompletely developed form or an individual variant of the Gulf species cannot be determined until Haeckel's type material is examined. For this reason a new name is not proposed for this taxon.
Distribution. This species is cosmopolitan in the Gulf but is rare at all stations where it occurs. It is absent at stations 27, 46, 90, 95, 99, 130, 184, 194, and all those to the north. It is present in slightly greater numbers in the southern half of the Gulf, particularly at stations 60, 64, and 81, but its general occurrence throughout most of the Gulf indicates nearly equal affinity for Gulf waters and Pacific waters. Its absence at most marginal localities indicates its preference for offshore, more nearly oceanic waters. It does not appear to respond to upwelling in the Gulf.
| | Benson 1966 | Benson, 1983, p. 507:
Pterocorys killmari (Renz)
Remarks. Because its test is “more cylindrical, very different from other hat-shaped Coracalyptra” (Renz, 1976, p. 118), I have placed this species in the genus Pterocorys (cephalis, thorax, abdomen with three solid thoracic wings; without terminal feet, Campbell, 1954, p. 130).
| | Benson 1983 |
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