Added below are some preliminary notes on mid-Cretaceous to Cenozoic ophiuroids that have been assigned to the genus Ophiura, either routinely, indiscriminately or with a query, listed according to stratigraphic age. Full revisions of these taxa are deferred to another occasion. Currently, no comparative basis exists that would allow the identification of dissociated ophiuroid remains to the species level. Possible exceptions may be certain types of vertebrae (i.e., the ‘keeled’ type) found exclusively in the families Ophiothrichidae Ljungman, 1867 and Ophionereididae Ljungman, 1867, as well as the genus Ophiopholis Müller & Troschel, 1842 (but not in the confamilial Ophiactis Lütken, 1856), as demonstrated by LeClair (1996) or the peculiar branching vertebrae that are found only in members of the families Gorgonocephalidae Ljungman, 1867 and Euryalidae Gray, 1840, or the ventrally closed vertebrae of the latter family. Those ossicles are, however, only useful at the family level. Martynov (2010) has recently suggested that ophiuroid families might be identifiable by arm spine articulation type, but more data are needed to validate this hypothesis. The majority of extant ophiuroid species cannot be identified solely on either the ventral or dorsal side, so that in the majority of cases, also in fossils, both sides need to be present. Often the ventral side is more informative, though, because the oral skeleton is critical for the classification of modern brittle stars.
At a disc diameter of 5–6 mm, Ophiura straini Cornell, LeMone & Norland, 1991 (p. 1010, figs. 2.1–2.4; holotype is SWBI 90-01), from the Smeltertown Formation (Albian) of New Mexico (USA) and referred by the authors to Ophiura with a query (aff.), has more numerous disc scales than O. paucilepis sp. nov. and the arm structure is different as well, with triangular dorsal arm plates. The overall habit of this species certainly is ophiurid, but details of the ventral disc surface and arm structure are needed to substantiate such an assignment. This same holds true for other mid-Cretaceous taxa from North America, such as Ophioglypha texana W.B. Clark, 1893 (p. 30, pl. 4, fig. 1a–c) from the Weno Member (upper Albian) of Texas (see also Berry 1941, p. 61, pl. 9, fig. 11; pl. 10, figs. 9, 11) and Ophioglypha graysonensis Alexander, 1931 (p. 152, pl. 20, figs. 19, 20) from the Grayson Member (lower Cenomanian) of Texas (see also Berry, 1941, p. 62, pl. 9, figs. 1, 10; pl. 10, figs. 1, 6–7, 10; pl. 11, figs. 8, 10, as Ophiura).
Later, Clark (1959) referred specimens from the Austin Chalk (Campanian) of Texas to O. graysonensis, but this assignment appears doubtful and a revision of this material is called for.
Arm fragments and dissociated arm ossicles from the Santonian to Maastrichtian of northwest Europe from the basis for the record of Ophiura serrata Roemer, 1840 by Wienberg Rasmussen (1950, p. 111, pl. 16, figs. 1–8), which is now assigned to the ophiodermatid genus Ophiotitanos Spencer, 1907 (see Jagt 2000). A new species from the lower Maastrichtian of southeast England, assigned with a query to Ophiura is Wienberg Rasmussen’s (1950, p. 114, pl. 17, figs. 1–5) O?. hagenowi, which Kutscher & Jagt (in Jagt, 2000, p. 69, pl. 24, figs. 1–6; pl. 33, fig. 1) provisionally transferred to the ophiurid genus Stegophiura Matsumoto 1915. A third species, Ophiura?
substriata Wienberg Rasmussen, 1950 (p. 116, pl. 18, figs. 1–9), from the Santonian to Maastrichtian of northwest Europe appears to be an ophiodermatid, which Jagt (2000, p. 28) listed as Ophioderma? substriatum.
On the basis of dissociated ossicles from the Kemp Clay (Upper Cretaceous, Maastrichtian) of Texas, Berry (1941, p. 64, text-fig. 1; pl. 9, figs. 2–9, 12–14; pl. 10, figs. 2–5, 8; pl. 11, figs. 1, 3–4, 7, 11–15) erected Ophiura travisana. His reconstruction suggests this form to differ clearly from O. paucilepis sp. nov. on the basis of adoral and oral shields.
Again with only dissociated ossicles at hand, Berry (1938, p. 66, pl. 14, figs. 1–10, 13–25) introduced Ophiura kunradeca. However, as noted by Jagt (1991, 2000) this ‘taxon’ comprises ossicle types of more than one species. In particular, the lateral arm plates and radial shields have been shown to belong to Felderophiura vanderhami Jagt, 1991, of which numerous discs with arms preserved are available for study. Felderophiura, originally considered to be an ophiurid, is an ophiolepidid.
Ophiura achatae Wienberg Rasmussen 1972 (p. 61, pl. 6, fig. 3; holotype is MGUH 12799), from the Sonja Sandstone Member (Agatdal Formation, upper Danian) of Nûgssuaq, West Greenland, is based on a single arm fragment. Compared to O. paucilepis sp. nov. this has longer arm spines (three in number), which are also in a different position, and contiguous ventral arm plates.
Ophiura bognoriensis Wienberg Rasmussen, 1972 (p. 66, pl. 8, figs. 1–10; pl. 14, fig. 1; holotype is NHM E 13761), from the lower Eocene London Clay of Bognor Regis, Sussex (UK), has more numerous disc scales (at 12 mm dd), larger-sized radial shields and the arm combs have more papillae. Moreover, ventral arm plates appear to have been smaller than in O. paucilepis sp. nov., even in proximal arm portions.
Ophiura furiae Wienberg Rasmussen, 1972 (p. 62, pl. 6, figs. 4–5; pl. 13, fig. 1; holotype is MGUH 12800), from the lower Eocene Mo Clay Formation of Fur, Denmark, is easily distinguished from O. paucilepis sp. nov. on details of ventral and dorsal arm plating, adoral and oral shields and dorsal disc scalation.
In Ophiura wetherelli Forbes, 1852 (p. 32, pl. 4, fig. 7; see also Wienberg Rasmussen, 1972, p. 64, pl. 7, figs. 1–5; pl. 13, figs. 2–3, with additional synonymy; lectotype is no. 99786, Institute of Geological Sciences, London), from the lower Eocene London Clay of London, disc scales (between 3.5 and 9 mm dd) are much more numerous, ventral arm plates do not abut, dorsal arm plates are narrower and triangular in distal direction, thus precluding confusion with O. paucilepis sp. nov.
Ophiura bartonensis Wienberg Rasmussen, 1972 (p. 68, pl. 9, figs. 1–9; pl. 14, figs. 2–4; holotype is NHM E 52158), from the upper Eocene at Barton, Hamsphire (UK), has triangular dorsal arm plates, non-contiguous ventral arm plates, an arm comb with more papillae, a large marginal disc plate and more numerous and smaller disc scales arranged in clear radial and interradial series, unlike O. paucilepis sp. nov.
Ophiura carpelloides Wienberg Rasmussen, 1972 (p. 71, pl. 10, figs. 1–9; holotype is NHM E 53658), from the upper Eocene of Barton, Hampshire, is based on dissociated ossicles only, and the structure of the oral shield and lateral arm plate suffice to distinguish that taxon easily from O. paucilepis sp. nov.
Ophiura costata Wienberg Rasmussen, 1972 (p. 70, pl. 6, figs. 8–9; holotype is NHM E 53637), from the upper Eocene of Barton, Hampshire, is based on dissociated lateral arm plates only. However, their structure suggests them to be asteroid oral ossicles rather than ophiuroid. In addition, the species name is preoccupied by Ophioglypha (=Ophiura) costata Lyman 1878.
Ophiura davisi Wienberg Rasmussen, 1972 (p. 75, pl. 10, figs. 10–15; holotype is NHM E 53668), from the upper Eocene at Barton, Hampshire, is based on dissociated lateral arm plates, which are easily differentiated from those of O. paucilepis sp. nov. by their denticulate external and internal articular surfaces.
Arm spine number (4) and length, shape of dorsal and ventral arm plates and the peculiar voids between the radial shields and arm combs serve to distinguish O. hendleri Blake & Aronson, 1998 (p. 348, figs. 5.1–5.8, 6.1–6.4, 7.1–7.4, 7.6), from the upper Eocene of Seymour Island, Antarctica.
Ophiura? sp. of Kutscher (1985, p. 8, pl. 3, fig. 1), from the middle Oligocene at Magdeburg, Germany, is based on a single lateral arm plate which appears to be much thinner than those of O. paucilepis sp. nov. and finely striate.
Ophiura?sternbergica Kutscher, 1980 (p. 226, pl. 2, figs. 4–7; pl. 3, figs. 4–5; pl. 4, figs. 1–7; holotype is SGWG 64), from the upper Oligocene ‘Sternberger Gestein’ of northeast Germany, is based mainly on dissociated ossicles, although an arm fragment is also known. Arm spines are three in number, but their position differs from that of spines in O. paucilepis sp. nov., and proximal lateral arm plates appear narrower while oral shields are medially constricted.
Ophiura?parviformis Küpper, 1954 (p. 161, pl. 15, figs. 4–14), from the ?lower ‘Badenian’ (=Langhian, mid-Miocene) of Austria, is an indeterminate species, based on isolated lateral arm plates only (see also Kroh, 2007, Table 4). It is certainly not an ophiurid, but compares much more favourably with some Late Cretaceous species assigned either to amphiurids or ophiothrichids (see e.g., Kutscher and Jagt, in Jagt 2000, pl. 29).
Ophiura?vindobonensis Küpper, 1954 (p. 162, pl. 14, figs. 9–17), from the ‘Badenian’ (=Langhian; see also Kroh, 2007, Fig. 4, Table 4) is either an ophiolepidid, close to some Late Cretaceous forms such as Ophiolepis? linea Kutscher & Jagt, in Jagt, 2000 (p. 86, pl. 26, figs. 3–6) or an ophiodermatid comparable to Ophiotitanosserrata, as based on spine base structure and peg-like articulation bosses.
Ophiura marylandica Berry, 1934 (see Berry, 1939, p. 87, text-fig. 1; pl. 1, figs. 1–3), from the upper Miocene of Maryland, has differently shaped oral and adoral shields and ventral arm plates and arm combs have more numerous papillae than in O. paucilepis sp. nov., at comparable diameters.