New species of Neogene radiolarians from the Southern Ocean - part II

Antarctic Neogene radiolarians are well preserved and offer great potential for biostratigraphical, palaeooceanographical and evolutionary studies. Most of the species, however, have not yet been fully documented. In this paper, the second of a planned series, we describe 21 new species of Antarctic Neogene radiolarians: six spumellarians (Actinomma eldredgei, Actinomma cocles, Anomalacantha? jeapica, Lonchosphaera? suzukii, Pentactinosphaera codonia and Sethodiscus? pravus) and fifteen nassellarians (Antarctissa evanida, Botryopera chippewa, Botryopera? daleki, Clathrocorys? sugiyamai, Clathromitra lemi, Clathromitra? fulgureanubes, Enneaphormis? sp., Lamprocyrtis? datureacornis, Lophocyrtis pallantae, Lithomelissa? kozoi, Phormospyris loliguncula, Platybursa harpoi, Saccospyris victoria, Protoscenium pantarhei and Trisulcus halipleumon). Most of these species are fairly rare but some can be locally common, and most have restricted stratigraphical ranges within the Miocene or Early Pliocene.

The radiolarian biozonation follows Lazarus (1992) and Abelmann (1992). The age estimates used for the range chart ( Fig. 2) are inferred linearly from an age model based on Gersonde et al. (1990) for Leg 113, Barron et al. (1991) for Leg 119, Harwood et al. (1992) for Leg 120 and Bohaty et al. (2003) for Leg 183, with all ages adjusted to the Berggren et al. (1995) time-scale. The relative abundances given in the range chart are drawn from counts made on 45 µm strewn slides for 84 of the c. 300 samples. Measurements were made on specimen pictures using ImageJ (Abramoff et al., 2004): the range of variation and the mean (between brackets) are both given in microns (µm) in the 'Dimensions' section for each species. Higher-level classification largely follows that of Riedel (1967), with a few subsequent emendations as individually noted below.
The terminology used here follows mostly Jørgensen (1905) and Petrushevskaya (1965; for nassellarian internal structure ( Fig. 3), Goll (1968) for features specific to the family Trissocyclidae and Boltovskoy (1998) for general external characters. The notation for connecting arches in nassellarians follows generally De Wever et al. (1979), Dumitrica (1991) and Funakawa (1995), in which they are named using a combination of the initials of the spines they originate from (i.e. arch aV would be an arch connecting spine a and spine V, see Fig. 3a), or, when necessary, follows Petrushevskaya (1965;, in which they are named after the apophyses they are joining (i.e. arch mj joins apophyses m on spine a and j on spine V, see Fig. 3b).
All holotypes are deposited in the micropaleontology collection of the Museum für Naturkunde, Berlin. ECO-xxx are the MfN accession numbers. Specimens are identified by a circle on the slide.

Fig. 2.
Range-chart of the 21 new species described herein. Antarctic radiolarian zonation follows Lazarus (1992) and Abelmann (1992). Numerical age of zonal boundary after Spencer-Cervato (1999), age scale is from Berggren et al. (1995). Width of bars corresponds to a rough estimate of the species abundance: dashed line is 'sporadic', plain line 'rare' (<0.5% of the assemblages) and bold line 'common' (>0.5%). A. challengerae, Amphymenium challengerae; u, upper; m, Middle; l, lower; Pleisto., Pleistocene; H., Holocene. the latter, being irregularly disposed, and the cortical shell, in the latter, being smaller, thicker and irregularly-shaped. diagnosis. Small three-shelled test with a small, eccentric innermost shell and a thin, spherical outermost shell close to the middle shell and linked to it by numerous thin radial bars.
Material. 126 specimens were observed from ODP Sites 689, 693, 748, 751 and 1138. description. The innermost shell is polyhedral to spherical, with polygonal pores (3 to 4 on a half-equator). The middle shell is spherical to globular (even ovoid in some rare specimens). Those two shells are connected to one another by the means of several thin beams that arise at the nodes of the innermost shell. The latter can be seen to be eccentrically placed in the middle shell cavity in most specimens. Pores on the middle shell are round to polygonal (7-9 on a half-equator). The outermost shell is a delicate meshwork of anastomosed bars branching from the numerous, thin beams that project from the middle shell. In most specimens that meshwork is poorly developed. The resulting shell outline generally mimics the middle shell outline. The two latter shells are close to one another, while the innermost shell is less than half the size of the middle shell. The two sets of connecting beams seem unrelated to one another.
dimensions. Based on 6 specimens. Diameter of medullary shell: 12-16 (15); diameter of inner cortical shell: 36-42 (38); diameter of outer cortical shell: 51-71 (58). occurrence. Rare from the Stylosphaera radiosa to the Cycladophora golli regipileus zone (Late Oligocene to Early Miocene) and from the Siphonosphaera vesuvius to the Tau zone (Late Miocene to Early Pliocene); sporadic from the Eucyrtidium punctatum to the Siphonosphaera vesuvius zone (Early to Late Miocene) and from the Tau to the Psi zone (Early Pliocene to Late Pleistocene). Haeckel, 1887, Helisoma dispar Blueford, 1982 and Drymyomma elegans Jørgensen, 1900 in having three shells, in its thin, delicate outermost shell and in its eccentric innermost shell. Excentrosphaerella sphaeroconcha Dumitrica, 1978 and Excentrodiscus japonicus (Nakaseko & Nishimura, 1974) also possess an eccentric innermost shell: however, the shell ratio and the thickness of the shell in these two species make them clearly distinguishable from this new species. Furthermore, although eccentric, the innermost shell in A. cocles is not fused to the next shell wall as in the two latter species (compare Pl. 1, fig. 3A with Nakaseko & Nishimura, 1974, pl. 3, fig. 7B, or with Kamikuri, 2010.
Material. 15 specimens were observed from ODP Site 748. description. Medullary shell is a small sphere composed of narrow, thick, crested bars surrounding a few (usually three on a half-equator) large, circular to elliptical pores. Seven to ten strong tribladed beams arise from the medullary shell, join the cortical shell and protrudes as spines (almost always found broken). Near the junction between the beams and the cortical shell, they broaden and, in some cases, branch and, therefore, join the shell at several points (see Pl. 1, fig. 9A).
The cortical shell is subspherical and two and a half to three times larger than the medullary shell. Bars are somewhat thinner than the ones on the medullary shell, but still crested. Pores are circular or elliptical and irregular in size (yet rather large), in shape and in distribution. The cortical shell is slightly deformed near the spines. Some of the bar nodes bear small thorns.
occurrence. Rare in the Stylosphaera radiosa zone (Late Oligocene to Early Miocene).

remarks.
Anomalacantha? jeapica has a medullary shell similar to that of A. dentata or Cladococcus pinetum Haeckel, 1887 but it differs from this species in having a latticed cortical shell. A.? jeapica also differs from Haeckeliella macrodoras (Haeckel, 1887) in Hollande & Enjumet (1960) in the smaller shell ratio, in the medullary shell being smaller, less spherical with crested bars. No complete specimen of A.? jeapica has been found so far, thus it is not possible to determine the distal shape of the spines. One specimen (Pl. 1, figs 11A, B) that we assigned tentatively to A.? jeapica, however, possesses spines that are serrated along their length, just as in A. dentata. This specimen differs from other specimens of our new species in its thinner medullary shell and in having numerous, well-developed thorns on its cortical shell.
Genus Lonchosphaera Popofsky, 1908 type species. Lonchosphaera spicata Popofsky, 1908. description. The medullary shell is a simple, delicate polyhedron from which arise seven (eight?) beams that join the cortical shell and protrude as fairly long, conical spines. In some specimens, the beams seem to be connected to each other, somewhere between the medullary and the cortical shell, by arches. The cortical shell is a rather thick sphere, with numerous small, subcircular, irregularly-distributed pores. The surface of the shell is crested and bears numerous conical by-spines often as long as the main spines and numerous small needle-like thorns. The main spines can, in some specimens, be tribladed at their base.
remarks. It differs from Lonchosphaera spicata in its cortical shell being a spherical, latticed shell with small pores instead of an irregular, thin meshwork of anastomosed bars. It also differs from it in the presence of numerous conical by-spines and numerous thorns. It differs from Actinomma delicatulum (Dogiel in Dogiel & Reshetnyak, 1952) in their respective medullary shells, in the latter having a thicker wall and fewer, bigger pores and in the main spines being, in Lonchosphaera? suzukii, similar in shape and size to the by-spines. It also differs from the specimen illustrated as Heliosoma sp. in Takahashi (1991, pl. 9, fig. 8) in that the spines, in the latter, are all connected to the medullary shell and in the bars between the pores being narrower. It finally differs from Actinosphaera acanthophora (Popofsky, 1912) in the radial beams being less numerous (c. 20 in the latter vs. c. 7 in L.? suzukii), the number of faces of the polyhedral medullary shell, the size of the pores and the size of the spines.
Regarding the specimens of the genus Lonchosphaera illustrated in Petrushevskaya (1975): the specimen identified as Lonchosphaera sp. B (pl. 17, figs 9-10) shares some external similarities with L.? suzukii but, because of the peculiar shape of the medullary shell in the latter, it is doubtful that they are conspecific; the specimen identified as Lonchosphaera sp. A (pl. 17, fig. 3) and two of the specimens identified as L. spicata (pl. 17, figs 4-5) differ from our new species in lacking additional by-spines and in their shell ratio, but they also differ from L. spicata in their thick latticed shell with small pores and large bars between them; the final specimen identified as L. spicata (pl. 17, figs 7-8) differs from L.? suzukii in its thin cortical shell with large pores and in lacking additional byspines as well. This specimen is closer to Popofsky's specimens but differs from them in its more regular cortical and medullary shell.
The cortical shell of L.? suzukii differs greatly from that described in Popofsky's (1908) diagnosis of the genus; however, because of the similarities in their medullary shell and their spines, we feel that L.? suzukii and L. spicata are closely related, hence the tentative generic assignment. Petrushevskaya's (1975) diagnosis for this genus varies from that of Popofsky (1908): our new species seems to fit better with her generic concept.
Genus Pentactinosphaera Nagata & Nishimura in Nakaseko et al. (1983)  description. Relatively small cortical shell of various thickness (though, most specimens have a rather thick wall) with large, circular to subcircular pores, separated by narrow, crested bars. The pores are arranged in a rather irregular hexagonal pattern. Some additional smaller pores sometimes disturb this pattern.
The medullary shell is similar to that of Pentactinosphaera hokurikuensis: it consists of an ellipsoidal to pyriform meshwork with a few large, elliptical to subpolygonal pores separated by thin bars; on one end of this shell (the apical end) is a beam joining the apex perpendicularly, and four lateral beams (Pl. 2, fig.  3A; Fig. 4); on the other end (the antapical end) is a sixth beam joining the shell at an acute angle with its elongation axis. Some specimens exhibit additional beams either on the apical side or on the antapical side (see Pl. 2, fig. 2B). The beams connect the medullary and the cortical shells and, in some rare specimens, can protrude as short conical spines (see Pl. 2, fig. 1B).
occurrence. Common in the Acrosphaera australis and the lower part of the Siphonosphaera vesuvius zone (Late Miocene) and then rare until the lower upsilon zone (Early Pliocene). Two specimens were also seen in the lower Cycladophora spongothorax zone (Middle Miocene).
remarks. Pentactinosphaera codonia differs from P. hokurikuensis in the latter having a typical very thick, double-layered outer shell. P. codonia is also noticeably smaller than P. hokurikuensis. It also differs from Thecosphaera akitaensis Nakaseko, 1972 in the shape and structure of the inner medullary shell and in lacking an outer medullary shell. P. codonia and P. hokurikuensis clearly share the same medullary shell structure, yet the cortical shell of the latter is so peculiar that it can render the assignment of our new species to genus Pentactinosphaera questionable. P. hokurukuensis was described previously (Kozur & Möstler, 1982;Nakaseko et al., 1982;1983) as belonging to the family Palaeoscenidiidae Riedel, 1967; however, as can be seen on Figure 4 and in Nakaseko et al. (1983, text- fig. 1), the four beams extending laterally from the medullary shell are not connected directly with the apical beam and are, therefore, not homologous with the Palaeoscenidiidae basal spines (see Dumitrica, 1978;Furutani, 1982;Goodbody, 1986 for Palaeoscenidiidae morphology). Without this homology, the resemblance between the medullary shell of P. hokurukuensis or P. codonia and the shell of the members of the Palaeoscenidiidae seem to be, in our opinion, only superficial.
De Wever et al. (2001) and Dumitrica (1985) relate the genus Pentactinosphaera to the family Hexalonchidae Haeckel, 1881 on the basis of the medullary shell structure described herein (referred to as a tetrapetaloid structure in De Wever et al., 2001). The only element of the structure they are describing that has not been recognized here is the element they referred to as being a 'median bar', by analogy (or homology) with the Nassellarian spicular element (Fig. 3), but it is possible that this element is either here reduced to a point, or simply that we were not able to see it due to the orientation of the specimens.
The specimen illustrated in De Wever et al. (2001, pl. 133, fig. 8) as Hexalonche sp. is very likely to be conspecific with our new species; however, since neither Haeckel's (1887, pls 22, 25) fig. 8). One or several thick beams on each side of the medullary shell and one or two at one of the apexes projects to join the cortical shell. Several other shorter beams also seem to project from the upper and the lower side (i.e. in the direction of the shell flattening; see Pl. 2, figs 7A, 10A, B) of the medullary shell and also connect to the cortical shell. The junction of these beams with the cortical shell creates, in most cases, a depression on the latter, thus deforming its outline from subcircular to clovershaped (see Pl. 2, figs 7A-8). In some specimens, the depth of the depression is irregular, in which case the outline can be reniform occurrence. Rare to common in the Stylosphaera radiosa zone (Late Oligocene to Early Miocene).
remarks. This species has been tentatively assigned to the genus Sethodiscus because of the flattening of the shell and the several short radial beams joining the medullary and the cortical shells. However, there are many differences between this species, S. macrococcus Haeckel, 1887 andS. lenticularis Haeckel, 1887 which includes a deformed cortical shell, pyriform medullary shell and radial beams in the equatorial plane as well as in the direction of the shell flattening. As was shown in Suzuki et al. (2009), the type species of the genus, Sethodiscus radiatum, is in fact a sponge spicule and not a radiolarian, which renders the genus improper for these forms. Pending a full revision of this group, however, we use Sethodiscus.
No specimen was seen in profile view, so the extent of the shell flattening cannot be assessed with certainty; however, under the microscope, the distance between the focal plane of the outer shell wall and that of the medullary shell wall seems very short (probably c. 5 µm).
Order nassellaria Ehrenberg, 1876 Family theoperidae Haeckel, 1881, emend. Riedel, 1967 Genus Lophocyrtis  description. Three-segmented shell with a small, subspherical, thick, crested cephalis, a short, campanulate thorax and a long, subcylindrical abdomen. Some rare, small, round pores can be seen on the cephalis. The thorax bears three to four transverse rows of hexagonally-framed, regularly shaped and sized, round pores while the pores on the abdomen, also arranged in transversal rows, are larger and somewhat irregular in shape, generally elliptical but ranging from round to subpolygonal. The upper abdominal pores of some highlysilicified specimens are infilled with a thin, cobweb-shaped feltwork (see Pl. 4, fig. 3B). The collar stricture is marked by rather deep furrows in the upper thorax. Near the collar, spine d protrudes as a short, hyaline, conical wing, directed perpendicularly to the shell main axis. A few specimens also bear two additional, shorter wings originating from spines ll and lr but in most specimens those were not seen. Spine a is attached to the cephalic wall by one or two apophyses and protrudes subapically as a rather thick, blade-like horn with, in some specimens, a somewhat tribladed base. Two arches al can be clearly seen on the inner side of the cephalic wall in most specimens. Spine V joins the cephalic wall above the collar stricture but does not protrude outside.
The lumbar stricture is marked by a constriction but there is only a slight change in contour. The abdomen flares distally and has a ragged termination.
occurrence. Common in the Stylosphaera radiosa zone (Late Oligocene to Early Miocene). Its last occurrence (LO) seems to be in the earlier Cycladophora antiqua zone (Early Miocene).
remarks. The cephalic structure of Lophocyrtis pallantae is similar to that described and illustrated for the genus in Sanfilippo & Caulet (1998), hence the generic assignment; however, it differs from the other lophocyrtids and from the specimens illustrated as Pterocyrtidium barbadiense (Ehrenberg) in Petrushevskaya & Kozlova (1972) mainly in its short thorax and the transversal alignment of the abdominal pores. It also differs in its d spine protruding as a short wing. The specimens illustrated as Nassellarian gen. et sp. #8 in Lazarus & Pallant (1989) appear conspecific with Pterocodon apis Ehrenberg, 1874 (see Ogane et al. (2009, pl. 5, figs 8a-d): they differ from our species in the presence of long, thin, dorsal and lateral wings, in the shape of the thorax, in the depth and width of the lumbar stricture, in the width ratio of the three segments and in the size and shape of the apical horn.
Ehrenberg's unpublished species 'Pterocanium graecum' (Ogane et al., 2009, pl. 25, figs 4a-d) differs from our species in having more numerous, smaller thoracic and abdominal pores, more numerous rows of thoracic pores and a deeper lumbar stricture.
(Pl. 4, figs 11A-12, 15A-C) derivation of name. Named after its apical horn that looks like a Datura flower: datureacornis is composed of datura with the suffix -eus denoting a resemblance and cornis, horn.
diagnosis. Hood-shaped cephalis with an open apex surrounded by a cluster of thorns; lateral lobes; flaring thorax with longitudinally-aligned pores.
Material. 11 specimens were observed from ODP Sites 748 and 751.
description. Two-segmented shell with a cephalis that is elongated apically on the dorsal side and a thorax that is, first, truncated-conical, then cylindrical and, finally, truncated-conical again.
The cephalis has a large eucephalic chamber and two lateral chambers (i.e. chambers situated laterally below the arches al; Pl. 4, figs 11A and 15B). The collar stricture is marked by a furrow following arches al and Vl. Spine a is free in the eucephalic cavity and continues as a complex horn disposed around an apical opening (Pl. 4, fig. 15B). This horn has several vertices (at least three): each pair of adjacent vertices is joined by a hyaline plate (sometimes perforated at its base; Pl. 4, fig. 12) whose upper boundary traces an elliptical arc between the two vertices.
At its widest, the cephalis often bears additional small thorns which do not seem to be connected to inner spines.
Pores on the cephalis are round, relatively large, closely packed and arranged according to a more or less regular hexagonal pattern. Pores on the thorax are larger; they are round, elliptical or subpolygonal and are aligned longitudinally. The thorax flares distally and seems to bear a few laterally projecting, spinelike teeth at its termination (Pl. 4, figs 12, 15B). remarks. Lamprocyrtis? datureacornis was assigned to the family Pterocorythidae on the basis of the presence of lateral lobes. However, the shape of its thorax, in particular, is very uncommon in this family. Because of its open-ended apex, this species was assigned tentatively to the genus Lamprocyrtis but there are dissimilarities with the other members of the genus: the two principal being a hood-shaped instead of a cylindrical cephalis and externally-expressed lateral lobes. The open-ended apex and the elongated cephalis are also a character found in some lophophaenids, such as Amphiplecta acrostoma Haeckel, 1887, or Lophophaena buetschlii (Haeckel, 1887; so an alternative hypothesis would be that L.? datureacornis is indeed a lophophaenid.
Lamprocyrtis? datureacornis differs from Lampromitra sinuosa Popofsky, 1913, in its elongated cephalis, its apical opening, its lateral lobes and the shape of its upper thorax. diagnosis. Dicyrtid with flaring thorax; double apically-located horn unrelated to spine a or spine V; three wings and numerous small 'feet'; internal skeletal structure similar to that of the genotype.
description. Two-segmented shell with a subspherical to slightly ovoid cephalis and a flaring thorax.
Cephalic inner structure is made of robust spines. Spines a and V join the cephalic wall at the collar stricture and, generally, do not continue outside: some rare specimens, though, exhibit a very small, triangular horn as continuation of both spines (Pl. 5, fig. 4B). Spine d is directed downward and reaches the thoracic wall near its middle. An apophyse c branches from spine d to join the upper thorax wall (Pl. 5, fig.  5B) and so is an apophyse a on spine a (Pl. 5, fig. 4B; Pl. 8, fig. 3). The axobate branches from the median bar close to the junction of spines a and d. It is fairly long, rod-shaped and ends with a cluster of thin branches (Pl. 5, fig. 8B). Spines ll and lr are fairly similar to spine d in shape and direction. Those three spines (ll, lr and d) protrude outside the thoracic wall as long, conical wings. In some specimens, bars connect these wings with the lower thorax (Pl. 5, fig. 5B).
The cephalis bears additional horns unconnected to inner spines: in particular, a strong, double (or even triple in some rare specimens; Pl. 5, fig. 2) horn is situated at the apex. Each branch of this horn is conical to blade-shaped and somewhat tribladed near the base. The other additional horns are small, needle-like and irregularly disposed. The cephalic wall is rough and bears several large, circular to subcircular pores, more or less regular in size and disposition, separated by crested bars.
The thoracic wall is rough and bears somewhat larger pores that are more irregularly sized, shaped and distributed than the ones on the cephalis. Some ribs are present on the lower half of the thorax: they continue as feet at the thorax end. Most specimens (such as the one in Pl. 5, figs 1A, B and 2) also bear on the lower half of the thorax, an extra ring of 'feet' made of thorns projecting from the bar nodes. In some specimens (Pl. 5, fig. 1A, B), furrows follow spines d, ll and lr, thus making the thorax trilobate in apical view.
occurrence. Common in the Tau and the lower upsilon zone (Early Pliocene); two specimens were encountered in the Siphonosphaera vesuvius zone (Late Miocene).
remarks. Antarctissa evanida differs from Antarctissa strelkovi Petrushevskaya, 1967 andHelotholus praevema Weaver, 1983 in its flaring thorax and in the presence of numerous 'feet' at its termination; from Lithomelissa? kozoi n. sp., Ceratocyrtis morawanensis Funakawa, 1995 and Ceratocyrtis cantharoides Sugiyama & Furutani, 1992 in the apical and ventral horn being, in these species, well developed; from Lophophaena simplex Funakawa, 1994 in its flaring thorax, its wings and its typical Antarctissa inner structure; from Lampromitra huxleyi (Haeckel, 1879) and from L. sinuosa Popofsky, 1913 in the shape and size of the cephalis, in the presence of wings and in the thoracic pores, in the latter, being polygonal. description. Two-segmented shell with a subspherical cephalis with two approximately equal cephalic horns projecting verticallylaterally and a cylindrical thorax of approximately the same size as the cephalis, separated by a collar stricture marked by shoulders along arches al and Vl. In most specimens the stricture is more pronounced ventrally than dorsally. Spine a is free in the cephalic cavity and protrudes outside subapically as a strong, smooth, blade-like horn, sometimes tribladed at its base. Spine V extends outside the wall as a short, triangular horn at the collar stricture. Spines d, ll and lr often continue as short blade-like wings/feet. An apophyse on spine d joins the thoracic wall. Some specimens have a long, slim axobate.
The median bar is generally situated below the upper third of the thorax.
The crested, thick cephalis wall bears few, rounded pores while the thoracic pores are increasingly numerous and big as they reach the thorax closure, which consists of a thinner meshwork with numerous small, irregular pores separated by thin bars.
occurrence. Sporadic from the Cycladophora golli regipileus to the Tau zone (Early Miocene to Early Pliocene). Petrushevskaya, 1975 and Botryopera oceanica (Ehrenberg, 1872) primarily in the strong spine a which protrudes subapically as a robust horn. It also differs from B. braevispicula (Popofsky, 1908) in having less numerous pores, in the clearer demarcation of the two segments and the stronger horns; from Dimelissa apis (Haeckel, 1887) (as illustrated in Petrushevskaya, 1971, pp. 134-135;pl. 69, figs I-Iv) in its longer thorax, its less numerous and smaller pores, its stronger horns and in the relative position of the median bar and the collar stricture; from Lithomelissa macroptera Ehrenberg, 1874 (see Ogane et al., 2009) in the latter having stronger, tribladed lateral and dorsal wings and in the relative position of the median bar and the collar stricture. The specimens illustrated in Chen (1975) as L. mitra? seem to be conspecific with Botryopera chippewa: they differ, however, from our specimens in being narrower and in having a less marked collar stricture. description. Two-segmented shell with a spherical cephalis and a truncate conical thorax, loosely connected to the lower third of the cephalis.

remarks. It differs from Antarctissa robusta
The inner cephalic structure is quite complex. It is composed of a proximal ring from which arise, on its upper side, four similar and regularly-spaced spines: a, V' and two spines l''. On the lower side of the proximal ring, spine d and the median bar are connected at the junction with spine a. The median bar bears an axobate (Pl. 6, figs 5A, B; Pl. 8, fig. 1) and bifurcates, on the ventral side, into spines ll and lr. These two spines are furthermore connected to the proximal ring by two vertical apophyses (called l-r in Sugiyama, 1993). Finally, two spines l' extend laterally from the proximal ring, close to the junction with spine a (see Fig. 5; Pl. 8, fig. 2A).
The eucephalic chamber is entirely supported by the arches connecting the four spines a, V' and l'' (i.e. what is referred to in Sugiyama (1993) as the distal ring, dr). The thorax is connected to the cephalis on those arches as well. Above this collar stricture, the cephalic wall is rather thick, crested, bears numerous thorns and numerous circular to elliptical small pores: there is an increasing pore size gradient from the apex to the collar stricture.
The upper part of the thorax (i.e. between the collar stricture and the junction of spines l', ll and lr with the thoracic wall) is cylindrical in outline whereas the lower part (i.e. below the level at which spines l', l1 and lr penetrate the shell wall) is truncated-conical. The thoracic wall is thin and bears numerous circular to subpolygonal relatively large pores, irregularly-disposed and separated by thin bars. The thorax termination is ragged.
Furrows at the junctions with spines l', ll, lr and d and the thoracic wall are often seen (Pl. 6, fig. 6A). occurrence. Rare in the Cycladophora golli regipileus zone (Early Miocene); sporadic from the Eucyrtidium punctatum to the Siphonosphaera vesuvius zone (Middle to Late Miocene). Petrushevskaya, 1975 in the shape, thickness and porosity of the thorax and the way it is attached to the cephalis; from Steganocubus subtilis Sugiyama, 1993, S. lipus Sugiyama, 1993, S. incrassatus Funakawa, 1995and Antarctissa? whitei Bjørklund, 1976a primarily in the clear external differentiation between the two segments; from Botryopera? leptostraca Sugiyama, 1993 in the loose attachment of the thorax to the cephalis and the width of the thorax.

remarks. Botryopera? daleki differs from Antarctissa cylindrica
This new species has been assigned tentatively to genus Botryopera because of the shape and size of the eucephalic chamber and the fact that the collar is situated in its lower third. However, the length and width of the thorax relative to that of its cephalis is uncommon for the genus. Internally, this species shares common characteristics with species of the genus Steganocubus Sugiyama, 1993 (such as the presence of a relatively narrow proximal ring with connecting spines l''); however, externally, they are very dissimilar. description. Two-segmented shell with a tetrahedral outline. The globular cephalis is four to five times shorter than the flaring thorax. Spine a is free in the cephalic cavity and extends subapically outside the wall as a tribladed horn that can be as long as the cephalis and that is commonly bearing panel-like projections at its base between the cephalic wall and the horn. Spine V protrudes as a shorter horn. The angle between spine a and spine V is approximately 70°. Spines d, ll and lr are directed downward, join the wall at the collar stricture and extend below as ribs on the thoracic wall. The median bar is short, subhorizontal and has not been observed to bear an axobate. None of the spines mentioned above seem to bear any additional apophyses. Pores on the generally crested cephalic wall are few, randomly distributed, uneven in size and globular.
The upper part of the thorax bears subelliptical, relatively small, sparse pores, whereas the lower part bears large, polygonal pores separated by thin bars and somewhat longitudinally aligned in some specimens. The three ribs extend below the ragged thorax termination as short diverging feet. Most specimens bear some projections along the ribs, which, in some specimens, end up forming a poorly-developed panel, bearing up to three longitudinal rows of large subelliptical pores.
dimensions. Based on 5 specimens. Length of cephalis: 37-51 (46); length of feet (from collar to end): 152-286 (225); height of apical horn: 28-44 (37); maximum width of thorax: 186-288 (218). occurrence. Rare from the Eucyrtidium punctatum to the Omega zone (Early Miocene to Holocene). Goll, 1979 primarily in having a fully-developed thorax and from Callimitra solocicribrata Takahashi, 1991 in its overall shape and in the poorly-developed panel along the thoracic ribs. It also differs from Genetrix petrushevskayae Sugiyama, 1994 in its spine a lacking apophyses a, in the shape of the thorax and in the latter having a somewhat spongy upper thorax. It finally differs from the specimen illustrated as Clathrocorys (?) sp. in Funakawa, 1994 in lacking the external ribs on the cephalis along arches al.
description. Tetrahedral to hemispherical one-segmented shell. The shell wall is a random meshwork of irregularly disposed, sized and shaped pores. In hemispherical specimens, the wall is usually thicker and crested (Pl. 7, figs 3A, B, 5A, B).
The inner spicule is rather thin and delicate and consists of spines a, d, ll and lr, plus an axobate formed by a cluster of small lumps on the median bar. Most of the apophyses drawn in text- fig. 3B are expressed here as rod-like spines that join the wall: on spine a, the three apophyses a are slightly directed upward (Pl. 7, fig. 5B), while the three short apophyses m are perpendicular to spine a (Pl. 7, fig. 2); on spine d, the two apophyses c can be seen (Pl. 7, figs 2, 3B, 6); on spines ll and lr, apophyses p can be quite long and robust (the upper one looks a lot like a spine V; Pl. 6, fig. 5B; Pl. 7, figs 3A, B, 5B) while apophyses d are short and perpendicular to spines ll and lr (Pl. 7, fig. 2). The wall tapers distally toward spines a, d, ll and lr. Spines a, d, ll and lr all continue as short, tribladed, sometimes serrated (Pl. 7, fig. 6) horn and feet (respectively). The feet are curved downwardly. occurrence. Rare from the Stylosphaera radiosa to the Cycladophora humerus zone (Early to Middle Miocene); sporadic from the Actinomma golownini to the Siphonosphaera vesuvius zone (Middle to Late Miocene). Haeckel, 1887 in its smaller size, short horn, feet, thinner inner spicule and in the overall tetrahedral shape of the shell. It is also distinguishable from C. pterophormis in the latter having a large axobate, robust, laterally-projected feet and a panelled apical horn. description. Shell consists of a single segment: a large angular cephalis covered by a tenuous meshwork of anastomosed bars and three divergent basal feet.

remarks. Clathromitra lemi differs from Archiscenium quadrispinum Haeckel, 1887 and from Clathromitra pentacantha
Spine a divides the cephalic chamber into two equal parts: in some specimens, though (Pl. 7, figs 7A, B), spine a is slightly closer to spine d. It is directed upward, perpendicularly to the median bar, and continues as a tribladed horn. Spines d, ll and lr are first directed laterally and then turn downward as long (for a distance approximately equal to the height of the cephalis), tribladed feet, serrated at their extremities. The axobate is a cluster of small lumps situated at the junction between spine a and the median bar. Large angular arches mc and mp form the two lobes of the cephalic chamber. Each lobe has a pentagonal outline.
The shell wall is thinner than the arches or the spines. The pores delimited by the anastomosed bars are irregularly disposed, irregularly shaped and sized. The shell wall is, in some specimens (Pl. 7, figs 8A, B), linked to apophyse g on spine a by several bars. occurrence. very sporadic from the Cycladophora golli regipileus to the lower Cycladophora spongothorax zone; rare from the Cycladophora spongothorax to the upsilon zone. remarks. Clathromitra? fulgureanubes differs from Clathromitra pterophormis, A. quadrispinum, C. pentacantha and C. lemi n. sp. primarily in its strongly marked arches. Similar arches are present in species of the genus Semantis, such as S. gracilis Popofsky, 1908, but C.? fulgureanubes differs from those species in its size and in the presence of a shell wall.
description. Large, flat (slightly convex) shell consisting of two segments. The cephalis is a third the diameter of the shell. A few specimens have been found with at least a small part of the cephalis remaining and none with a complete cephalis. It seems to be a very delicate 'velum' consisting of a feltwork of thin, anastomosed bars delimiting numerous polygonal pores. The cephalis encroaches on to the thorax and attaches to the rim of some of the large thoracic pores (Pl. 7, figs 10, 14). The inner spicule was not observed in any of the specimens; however, three ribs originating from the cephalic structure are clearly distinguishable on the thorax of most specimens (Pl. 7, figs 10, 12, 14) and most probably represent extensions of spines d, ll and lr.
The thorax consists of a network of large polygonal pores of various sizes and a very irregular 'honey-comb' disposition. The thorax ends with an irregular but not ragged, almost circular, rim. On most specimens (Pl. 7,figs 10,(13)(14), several small, circular pores can be seen adjacent to the rim: in some specimens they are aggregated in small clusters (Pl. 7, fig. 13).
occurrence. Rare to sporadic from the upsilon to the Chi zone (Late Pliocene to Early Pleistocene).
remarks. Since a specimen with a completely preserved cephalis is yet to be found, the generic assignment of this species is problematic: indeed, the cephalic 'velum', coupled with the three radial ribs, seems characteristic of the genus Enneaphormis; yet the porosity of the thorax and its rim are morphological features that seem more coherent with the genus Lampromitra Haeckel, 1881. This species differs from Sethophormis aurelia (Haeckel, 1879) in possessing three radial ribs instead of four, in the size and shape of its thoracic pores and in the thorax ending with a rim. It is distinguished from Lampromitra coronata Haeckel, 1887 in its velum-shaped cephalis, in the size of the thoracic pores, the flatness of the shell and the absence of spines on the rim. It finally differs from Velicucullus oddgurneri Bjørklund, 1976a in the size and shape of the thoracic pores and in the latter having its cephalis and thorax raised with regard to the lower thorax.
Because a complete specimen is yet to be found, we leave this species in open nomenclature.
Genus Lithomelissa Ehrenberg, 1847 sensu Petrushevskaya, 1971 type species. Lithomelissa microptera Ehrenberg, 1854a. description. The shell consists of two segments: a short cephalis and a flaring thorax. The collar stricture is marked by shoulders (that can be strongly expressed in some specimens) and furrows following arches al and Vl.
Spine a is fused to the dorsal side of the cephalis and protrudes subapically as a slightly ventrally-curved horn (approximately as long as the cephalis), the base of which is weakly tribladed while the rest of the horn is conical. Spine V protrudes at the collar stricture or a little below as a short triangular horn (Pl. 8, fig. 5). The axobate can sometimes be seen as a small knob near the junction between spine V and the median bar. Spines ll and lr reach the thoracic wall and continue as (primary) ribs to the thorax termination where they go on as short, thin, conical tooth-like feet while spine d reaches the thoracic wall very close to its end so that it extends effectively as a foot. Both spines l' follows the same pattern as spines ll and lr: they continue as secondary ribs and terminate as small feet comparable to the previous ones. A short apophyse on each spine l' sometimes protrudes at the point where the spines join the thoracic wall, as very short and thin wings (Pl. 5, figs 11, 13A). An apophyse on spine d, comparable to that typical of genus Antarctissa, can also be seen, joining spine d and the thoracic wall halfway down (Pl. 5, fig. 10A; Pl. 8, fig. 5).
Pores on the cephalic wall are elliptical, closely packed and rather large. Pores on the thorax are somewhat larger but less densely packed and are randomly sized, shaped and arranged. Pores near the thorax termination are downwardly-elongated so that the bars between them appear in some specimens as additional small teeth. occurrence. Rare from the Tau to the Chi zone (Early Pliocene to Early Pleistocene). One specimen was also seen in the Omega zone (Holocene) of ODP Site 747 and two specimens in the Acrosphaera australis zone (Late Miocene) of ODP Site 747 were also tentatively assigned to this species (Pl. 5, fig. 15). This species was reported in Takahashi (1987), Itaki et al. (2008) and Itaki (2009) in the Holocene of the Japan Sea and the North Pacific.
remarks. This species, together with others such as Lithomelissa stigi Bjørklund, 1976a, Ceratocyrtis morawanensis Funakawa, 1995(=Lophophaena tekopua O'Connor, 1997, C. cantharoides Sugiyama & Furutani, 1992, Lophophaena? thaumasia Caulet, 1991, Lophophaena leberu Renaudie & Lazarus, 2012, or even Pseudodictyophimus tanythorax Funakawa, 1994, despite being scattered in several genera, all share some common morphological features, such as the separation of the two segments by shoulders along arches al and Vl, a well-developed apical horn protruding subapically and a vertical horn protruding at the collar. The taxonomy of this group needs to be resolved, but in the meantime, we are tentatively assigning this new species to the genus Lithomelissa. L.? kozoi differs from L. stigi, L. thaumasia, L. leberu and Trisulcus nanus Popofsky, 1913 in its flaring thorax and its ribs/feet; from C. morawanensis and C. cantharoides in lacking the longitudinal pore alignment and in having only five ribs/ feet: three primary derived from spines d, ll and lr and two secondary derived from the two spines l'. It finally differs from Pseudodictyophimus hexaptesimus  in that the ribs in the latter protrude as tribladed feet and wings originating from the three primary spines and the three secondary spines, respectively. Genus Protoscenium Jørgensen, 1905 type species. Plectacanium simplex Cleve, 1900. description. Skeleton consists almost entirely of the initial spicule, comprising spines a, d, ll and lr. Spines d, ll and lr are identical in shape and size; they are also more or less in the same plane. In apical view (Pl. 6, figs 8A, B), they are separated from each other by a 120° angle. Apophyses c and p bifurcate from spines d, ll and lr in their distal half; they are also situated more or less in the basal plane. The median bar is extremely reduced but is more than just a point since spine a joins the  fig. 9a, b. Clathromitra lemi n. sp., sample 120-748B-6H-5, 45-47 cm -(A) focus on wall, (B) focus on inner spicule. fig.  10a, b. Platybursa harpoi n. sp., sample 120-747A-2H-3, 45-47 cm, specimen with an apical horn, seen in ventral view. Scale bars are 50 µm except for figs 6 and 8 where it is 100 µm. Magnification is ×384 except for figs 6 and 8 (×192). spicule 1 or 2 µm away from the junction of spines ll and lr. The axobate, when present, is a short cluster of lumps (Pl. 6, fig.  8B). Spine a is almost perpendicular to the basal plane. Three apophyses m bifurcate from it in its distal third and are upwardly directed. Arches mc and mp are usually present and can be strongly expressed in some specimens (Pl. 6, figs 14A, B). Some specimens also exhibit arches mg (Pl. 6, fig. 12B).
The shell wall rests on the arches and is connected to the distal end of all spines and apophyses, with the exception of spine a which protrudes apically. The wall consists of randomly distributed anatomising thin bars, branching from a multitude of small, needle-like thorns arising from the arches (Pl. 6, fig. 12B). When complete, the shell wall has a somewhat hemispherical outline. In some specimens (Pl. 6,figs 12A,B and 14A,B), the wall extends slightly below the basal plane.
occurrence. Sporadic from the Cycladophora golli regipileus to the Eucyrtidium punctatum zone (Early to Middle Miocene); rare to common from the Cycladophora humerus to the Acrosphaera? labrata zone (Middle to Late Miocene); sporadic again from the Acrosphaera? labrata to the Tau zone (Late Miocene to Early Pliocene) and then rare again in the upsilon zone (Early to Late Pliocene).
remarks. Protoscenium pantarhei and P. simplex exhibit more or less the same skeletal pattern; however, the presence of a wall, the size of the specimen and the thickness of the spines differentiate P. pantarhei from the latter.
Material. 39 specimens were observed from ODP Site 748.
description. Small dicyrtid with a relatively small cephalis subhemispherical externally and a cupola-shaped thorax. The two segments are separated by shoulders and furrows that can be more or less pronounced. There is a small change in contour between the two segments, which tend to disappear in some specimens.
Spine a is fused to the dorsal side of the cephalic wall and protrudes subapically as a small, barely noticeable, triangular horn. Spine V is short and joins the wall at the collar: it protrudes outside in some specimens as a small triangular horn similar to the apical one (Pl. 5, fig. 9B). Spines d, ll, lr and the two l' reach the thoracic wall at its widest point and become strong ribs that continue as medium-length, tribladed, downwarddirected feet at the termination of the thorax. Two apophyses can be seen joining spine d and the thoracic wall in the upper thorax. Arches al can be clearly seen in some specimens on the inner side of the shoulders (Pl. 5, fig. 6B). The axobate appears in some specimens as a stubby, triangular spine. The median bar and the other inner spines are all relatively thick compared to the size of the total shell.
Cephalic pores are rather small, irregular in size and pattern and generally rounded. The cephalic wall between the pores is crested. Thoracic pores are larger, also irregular in size and pattern and elliptical. There is somewhat of a size gradient toward the thorax ragged end.
Some rare specimens exhibit supplementary ribs in their lower part.
occurrence. Rare to common in the Stylosphaera radiosa zone (Late Oligocene to Early Miocene). Popofsky, 1913 andT. pinguiculus Renaudie &Lazarus, 2012 in its five tribladed feet and in the relative width of the thorax compared to the cephalis. It also differs from Lithomelissa? kozoi n. sp. in its porosity, the size and degree of immersion of the cephalis in the thorax and the shape of the thorax itself.

remarks. It differs from Trisulcus triacanthus
Family trissocyclidae Haeckel, 1881emend. Goll, 1968Genus Platybursa Haeckel, 1881emend. Petrushevskaya, 1971 type species. Cantharospyris platybursa Haeckel, 1887. Platybursa harpoi n. sp. (Pl. 2, figs 11A-16B;Pl. 3, figs 10A, B) ?1975 Platybursa sp. Petrushevskaya: pl. 8, fig. 5. derivation of name. Named in honour of 'Harpo' Marx (1888-1964 of the Marx Brothers, who popularized harp music; suggested by the resemblance of the sagittal ring in this species to a musical harp. diagnosis. Trissocyclid with a thick, apically-elongated sagittal ring; numerous apophyses link spine V and the latticed shell. description. D-shaped, thick, apically-elongated sagittal ring with a shorter, conical, downward-directed spine d. Spines l' are similar in size and shape to spine d but project laterally. Spines ll and lr also project laterally and terminate in several short bifurcations (Pl. 2, fig. 16B). A short, triangular axobate can also be seen below the junction of the median bar and spines ll and lr.
The latticed shell is connected to spine a, spines ll and lr, spines l'. It is also connected to spine V by numerous small apophyses (Pl. 2, figs 14, 16A).
The latticed shell has no sagittal constriction and bears numerous circular, elliptical or sometimes polygonal, irregularly-disposed generally small pores of various sizes. The width of the bars between the pores varies widely between the specimens or even on one single specimen (Pl. 2, fig. 13A). Typically, the shell outline is semi-ellipsoidal with a rounded apex but it can be more irregularly-shaped in some rare specimens (Pl. 2, figs 11A, B, 13A, B). Some specimens exhibit a small, conical apical horn (Pl. 3, figs 10A, B).
occurrence. Common in the Chi zone (Early Pleistocene); four specimens have also been found in the lower upsilon zone (Early Pliocene).
occurrence. Rare from the Siphonosphaera vesuvius to the Tau zone (Late Miocene to Early Pliocene).

remarks. Phormospyris loliguncula differs from
Triceraspyris antarctica (Haecker, 1907), T. pacifica Clark, 1942 andT. coronata Weaver, 1976 in its large dorsal sagittal-lattice pores and having five or more feet. It also differs from Ceratospyris laventaensis Clark & Campbell, 1942 in its other pores being small and round, in the overall shape of the cephalis, in the latticed thorax and in the absence of spines on the cephalis.
Saccospyris victoria n. sp. (Pl. 4, figs 9A-10B, 13-14B, 16, 17) derivation of name. Named after the 'Winged victory of Samothrace', for the resemblance between the holotype and the shape of this statue; the Latin word victoria being a generic name for statues of the goddess victory.
Material. 122 specimens observed from ODP Sites 689, 693, 748, 751 and 1138. description. Two-segmented shell. The cephalis is separated into the antecephalic and eucephalic chambers (some specimens show a small, reduced postcephalic chamber: Pl. 4, figs 14A, B). These two chambers are equal in size and shape (hemispherical). Spine a separates the two chambers and protrudes outside as a thin, short apical horn (some specimens have a stronger apical horn; Pl. 4, figs 16, 17). The collar shows a more or less marked stricture.
The thorax is fairly long and truncated-conical. Pores on the thorax are small, numerous, usually round, but vary in size and shape. They are randomly disposed. Pores on the cephalis are similar to that of the thorax, yet somewhat smaller. Cephalis and upper thoracic wall bear numerous small, thin thorns that, in some specimens (Pl. 4, figs 13-14B, 16), connect distally to form a thin peripheral feltwork.
occurrence. Rare from the Actinomma golownini to the Siphonosphaera vesuvius zone (Middle to Late Miocene). Sporadic from the Siphonosphaera vesuvius to the lower Tau zone (Late Miocene).
remarks. Saccospyris victoria differs from Saccospyris antarctica and S. praeantarctica Petrushevskaya, 1975 in its long, flaring thorax, which is wider than the two cephalic chambers, in the presence of a peripheral spongiose meshwork on the upper thorax of some specimens and in the numerous small pores covering the entire test.
Saccospyris victoria shares with Lophophaena apiculata Ehrenberg, 1874 (see Ogane et al., 2009, pl. 19, figs 3A-d) the presence of a bilobed cephalis separated by a free spine a and a skirt-looking thorax but differs in the apical constriction being stronger, the smaller size of the cephalis compared to the thorax and the lack of longitudinal lineation in the thoracic pores.