Pelagomanes cantharoides ( Sugiyama and Furutani, 1992 ) Trubovitz, Sarah, Renaudie, Johan, Lazarus, David & Noble, Paula, 2022

Trubovitz, Sarah, Renaudie, Johan, Lazarus, David & Noble, Paula, 2022, Late Neogene Lophophaenidae (Nassellaria, Radiolaria) from the eastern equatorial Pacific, Zootaxa 5160 (1), pp. 1-158 : 80

Pelagomanes cantharoides ( Sugiyama and Furutani, 1992) n. comb.

Plate 40, Figs. 1–3 , 7–8 , 10 , 14 .

Ceratocyrtis? cantharoides n. sp., Sugiyama and Furutani, 1992, pl. 13, figs. 1–2; pl. 20, figs. 1–2b.

Ceratocyrtis sp. aff. C. cucullaris (Ehrenberg) , Tsoy and Shastina, 1999, pl. 35, fig. 6.

Ceratocyrtis? cantharoides Sugiyama and Furutani, Renaudie, 2014 , pl. 22, fig. 3.

Ceratocyrtis cantharoides Sugiyama and Furutani, Trubovitz et al., 2020 , supplementary data 7.

Remarks. Sugiyama and Furutani (1992) only tentatively placed this species in Ceratocyrtis because it lacks the well-developed, dendritic axobate that is typical of Ceratocyrtis species. The authors state that the apical horn has 1–2 branches on the dorsal side. It is this forked apical horn that separates P. cantharoides from similar taxa (i.e., P. morawanensis and P. tekopua ). However, it is unclear whether this character alone should justify the separation of this species from P. morawanensis (Funakawa) . Plate 40 demonstrates that specimens sharing the character of a forked apical horn often have as many differences between one another as with specimens without a forked horn. This suggests that a forked horn may not be a reliable distinguishing character, and these two species concepts may require revision. Here we provisionally accept these two concepts as separate species, but acknowledge that further study may show they are the same.

Range. Middle Miocene in the EEP, though the range in our material is not well constrained ( Table 1 ). Sugiyama and Furutani (1992) described this species from the Middle Miocene of Japan. Renaudie (2014) reported it from the Early–Middle Miocene of the Southern Ocean.

Figures

FIGURE 1. Diagram illustrating the general skeletal morphology of Lophophaenidae, and terminology used in this manuscript. Dashed lines indicate spines that are not visible from the angle shown, as they extend into the skeleton. An example specimen of Lophophaena casperi n. sp. is included for comparison to the diagrams.

FIGURE 2. Relative abundance of specimens and taxa belonging to Plagiacanthoidea and Lophophaenidae per sample, from IODP Site U1337 in the EEP over the last ~10 Ma. The relative percentages of total taxa are represented by the blue lines and the red lines represent the percentages of total specimens (triangles = Plagiacanthoidea; circles = Lophophaenidae). The Plagiacanthoidea was among the most abundant and speciose of radiolarian groups encountered in Trubovitz et al. (2020), with at least 10% of the specimens and 20% of the taxonomic richness in every sample. Within the Plagiacanthoidea, lophophaenids consistently made up the majority of specimens (~67%) and taxa (~61%). Data are from Trubovitz et al. (2020).

FIGURE 3. Locality map of IODP Site U1337, where all samples for this study were collected. Map from Google EarthTM.

FIGURE 7. Internal skeletal structure of Arachnocorys umbellifera (Haeckel, 1862) Petrushevskaya, 1971.

FIGURE 8. Internal skeletal structure of Botryopera amabie n. sp.

FIGURE 10. Internal skeletal structure of Lithomelissa alkonost n. sp.

FIGURE 14. Chart illustrating the different cephalis sizes in Lophophaena shishigae n. sp. and Arachnocorys jorogumoae n. sp. The yellow circles indicate L. shishigae, with a small cephalis, and the purple triangles represent A. jorogumoae, with a significantly larger and proportionally higher cephalis.