radiolaria - rads_cenozoic - Siphocampe grantmackiei radiolaria - rads_cenozoic - Siphocampe grantmackiei

Siphocampe grantmackiei

Classification: rads_cenozoic -> Artostrobiidae -> Siphocampe -> Siphocampe grantmackiei
Sister taxa: S. acephala, S. altamontensis, S. arachnea, S. bassilis, S. daseia, S. elizabethae, S. grantmackiei, S. imbricata, S. lineata, S. minuta, S. modeloensis, S. nodosaria, S. pachyderma, S. quadrata, S. septata, S. stathmeporoides, S. sp.


Citation: Siphocampe grantmackiei O'Connor 1997
taxonomic rank: species
Basionym: Siphocampe grantmackiei
1997 Siphocampe grantmackiei - O_Connor p. 106, pl.1, fig. 5-8; pl. 4, fig. 7-12
Taxonomic discussion: O'Connor, 1997

Catalog entries: Siphocampe grantmackiei

Original description: Description: Shell of three segments, hyaline, pupoid, abdomen divided into sub-segments. Cephalis ovoid, smooth-surfaced, lower 1/3 sunk into upper thorax. Pores few, circular to subcircular, irregularly distributed. Well developed vertical tube (approx. 8-10μm long) projects upward at 24-34° angle, generally circular in cross-section (approx. 8µm diameter), tapers distally, may have slight distal flare. Lateral lobes externally delineated by furrows (see below). Vertical spine well developed (1/3 to 1/2 length of vertical tube), protrudes freely into vertical tube (see below). Small, conical to bladed apical horn anteriorly offset on cephalis (see below). Collar stricture externally indistinct. Thorax inflated truncate-conical, bears three to four transverse rows of circular to subcircular pores. Occasionally small wings present: one corresponding to D (see below) protrudes anteriorly from upper thorax (pl.l, fig.6, pi.4, fig.9); another corresponding to Vbd (see below) protrudes posteriorly from upper thorax just below vertical tube (pl.l, figs.7, 8, pl.4, figs.9, 10). Lumbar stricture externally distinct as smooth, rounded constriction, seen internally as ledge or ring. Abdomen pupoid, divided into series of six sub-segments by smooth, shallow, rounded, external constrictions (not defined by ledge or ring internally): two transverse rows of circular to subcircular pores on first sub-segment, two to three rows on second and one row on each of following four. Maximum width of shell attained by third or fourth sub-segment. Aperture slightly constricted, termination ragged as though broken along a transverse pore row. On some specimens an incipient peristome present, smooth-surfaced, with slightly ragged termination. Surface of thorax and abdomen covered in wavy longitudinal ridges that gradually become less pronounced distally and disappear before termination so last sub-segment of abdomen smooth-surfaced. Internal skeleton consists of bars M, D, V, A, LI, Lr, 11, Ir, Vbl, Vbr, Vbd, spines Vs. seven Ax and arches A-Vbl, A-Vbr, Vbl-Vbd. Vbr-Vbd, LI-Vbl, Lr-Vbr, 11-L1, Ir-Lr, D-Il and D-lr (text-fig.4; pl.4, fig.l 1, 12). A extends freely upward from M to top of cephalis protruding as tiny apical horn (see above); small antecephalic lobe anterior to A. D extends downward at an angle to collar stricture, may protrude outside as small dorsal wing (see above). V extends upward at an angle, branches to form Vbl, Vbr and Vbd. Vbl and Vbr extend laterally to join cephalic wall at either side of base of vertical tube. Vbd extends downward at an angle to join cephalic wall at lower base of vertical tube, may protrude outside as small wing (see above). Rest of bars extend to cephalic wall and do not penetrate. Vs continues from V extending freely into vertical tube. Seven Ax extend straight downward - one from junction of V and M, shorter than others; two each from bars M, LI and Lr near their junction with each other. Ax may be hollow. Arches A-Vbl and A-Vbr mostly incorporated in cephalic wall so internally indistinct, curve downward from point where A joins cephalic wall to join Vbl and Vbr at cephalic wall; define lateral lobes (see above). Arches Vbl-Vbd and Vbr-Vbd form partial ring at lower part of base of vertical tube and together with rest of arches form ring at base of cephalis.  


Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within Neogene Period (2.59-23.03Ma, top in Piacenzian stage). Data source: Lazarus et al. 2015 - "N age group"
First occurrence (base): within Neogene Period (2.59-23.03Ma, base in Aquitanian stage). Data source: Lazarus et al. 2015 - "N age group"

Plot of occurrence data:


O'Connor, B. (1997a). Lower Miocene Radiolaria from Te Kopua Point, Kaipara Harbour, New Zealand. Micropaleontology. 43(2): 101-128. gs


Siphocampe grantmackiei compiled by the radiolaria@mikrotax project team viewed: 25-7-2024

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