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Botryostrobus hollisi O'Connor, 1997

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Shell of five segments, hyaline, pupoid. Last segment cylindrical to truncate-ovoid. Cephalis ovoid, smooth-surfaced, thick-walled, lower 1/3 to 1/2 sunk into upper thorax. Pores irregularly distributed, circular to subcircular, relatively large. Tiny, conical apical horn ma) be present, anteriorly offset on cephalis (see below). Well developed, short (approx. 6-7pm long) vertical tube, generally circular in cross-section (approx. 7μm diameter), projects upward at 18-25 angle, tapers dislally. Lateral lobes externally delineated by furrows (see below). Vertical spine short (maximum length 1/3 that of vertical tube), projects freely into vertical tube (see below). Collar stricture externally indistinct. Thorax truncate-spheroidal, thick-walled, smooth-surfaced, bears three to lour transverse pore rows. Pores circular to subcircular, generally larger than those on cephalis; those of distalmost row larger, downwardly-directed giving them arched appearance. Lumbar stricture externally distinct as smooth, rounded constriction. Abdomen truncate-spheroidal to inflated truncate-conical, wider and thinner-walled than thorax, bears two transverse pore rows. Pores circular to subcircular. smaller than those on thorax. Stricture between abdomen and fourth segment of same form as lumbar stricture. Fourth segment same as abdomen but wider and generally longer, bears three to four transverse rows of circular to subcircular pores. Stricture between fourth and fifth segments same as above. Fifth segment cylindrical to truncate-ovoid, thinner walled than thorax, wider proximally than dislally. widest part is widest part of shell, bears four to six transverse pore rows of circular to subcircular pores. Smooth, porcless peristome terminates smoothly in constricted aperture. Entire post-thoracic shell, except for peristome, covered in longitudinal, wavy ridges. Internal skeleton consists of bars M, D, V, A, Ll, Lr, ll, lr, Vbl, Vbr, Vbd, spines Ax, Vs and arches A-Vbl. A-Vbr, Vhl-Vbd, Vbr-Vbd, Ll-Vbl, Lr-Vhr, ll-Ll, lr-Lr. D-ll and D-lr (text- fig.3; pl.5. fig.4). A extends freely upward from M, may project outside as tiny apical horn (see above): small antecephalic lobe anterior to A. V extends upward at an angle from M, branches to form Vbl, Vbr and Vbd. Vbl and Vbr extend laterally from V to join cephalic wall at either side of base of vertical tube. Vbd thin, extends downward at an angle from V to join cephalic wall at lower base of vertical tube. Rest of bats extend to cephalic wall and do no penetrate. Vs thin, continues from V extending short way into vertical tube (see above). Ax short, extends straight downward. Arches A-Vbl and A-Vbr mostly incorporated in cephalic wall so internally indistinct: begin where A joins cephalic wall, curve initially upward to highest point of cephalis then downward to join Vbl and Vbr at cephalic wall: define lateral lobes (see above). Arches Vbl-Vbd and Vbr-Vbd form partial ring al lower part of base of vertical tube and together with rest of arches form ring at base of cephalis.

Holotype (range of 20 specimens): length of cephalis: 20μm (18-20); maximum width ol cephalis: 25μm (25-30): length of thorax: 25μm (22-25): maximum width of thorax: 47μm (44-52): length of abdomen: 25μm (20-28); maximum width of abdomen: 60μm (48-60): length of fourth segment: 30μm (25-53): maximum width of fourth segment: 72μm (57-731: length of fifth segment: 70μm (60-90); maximum width of fifth segment: 81μm (63-81).

This species is named in honour of Dr Chris Hollis of the Institute of Geological and Nuclear Sciences, who has provided me with much help, advice and encouragement over the past few years.

Holotype: R261 (Plate I. figures 9. 10).

Type Locality: Te Kopua Point. Q08/254532

Abundance and Range: Botryostrobus hollisi is rare in both samples Q08/f569 and Q08/F570 and has been observed in the upper Stichocorys delmontensis Zone / lower Stichocorys wolfii Zone (early Miocene (mid-Otaian)).

O'Connor 1997











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