Ceratocyrtis sp. I

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 : 37

Ceratocyrtis sp. I group

Plate. 14, Figs. 3A – 6B .

Ceratocyrtis sp 7 cf, Trubovitz et al., 2020, supplementary data 7.

Remarks. This species group is unique for its relatively heavily silicified cephalis, and long, thin thorax with semiirregular pores that remain similar in size throughout the length of the thorax. It differs from C. cucullaris (Pl. 10, Fig. 1 ) in that the thorax does not flare as widely outward, and it has a relatively thin thorax wall. It differs from C. histricosus (Pl. 10, Figs. 2–3 ) in that it generally grows a much longer thorax, and the pores on the thorax do not substantially increase in size toward the bottom. We list this as a species group rather than a single species because the simple morphology and lack of constraint in morphological variability make it difficult to determine whether this is one species or multiple.

Material examined. 10 specimens observed from Late Miocene samples 321-1337D-23H- 6, 134–137cm, 321- 1337A-18H-6, 77–80cm, and 321-1337A-16H- 6, 121–124cm.

Range. Late Miocene in the EEP ( Table 1 ).

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 6. Internal skeletal structure of Arachnocorallium calvata (Haeckel, 1887) Petrushevskaya, 1971.