Pelagomanes tekopua ( O’Connor, 1997 ) 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 : 83

Pelagomanes tekopua ( O’Connor, 1997) n. comb.

Plate 40, Fig. 13 .

Pseudodictyophimus sp. B, O’Connor, 1993 , pl. 6, figs. 14–15.

Lophophaena tekopua n. sp., O’Connor, 1997, pl. 2, figs. 11–14, pl. 7, figs. 7–10.

Lophophaena tekopua O’Connor, Kamikuri, 2019 , pl. 14, fig. 14 (non fig. 13).

Remarks. This species is very similar to Pelagomanes cantharoides (Pl. 40, Figs. 1–3 , 7–8 , 10 , 14 ) and P. morawanensis (Pl. 40, Figs. 4A – 6 , 9 , 11–12), and O’Connor (1997) provided no differential diagnosis between any of these species. The type material of this species appears to indicate a relatively larger cephalis:thorax ratio than either Pelagomanes cantharoides or P. morawanensis . However, the range of variability is not clear and we are not certain that this is indeed a separate species. Renaudie 2014 considered Lophophaena tekopua O’Connor along with Pseudodictyophimus sp. B O’Connor to be conspecific with P. morawanensis (Funakawa) . Kamikuri (2019) identified two specimens as Lophophaena tekopua O’Connor ; one of these is almost identical to the type material illustrated by O’Connor, and the other appears to more closely match the original illustrations of P. morawanensis . It is not evident to us whether these are two endpoints on a morphological continuum, or two distinct morphotypes that should be considered separate species. The group of taxa including P. cantharoides , P. morawanensis , and P. tekopua will require further work to determine the consistent differences between species, if there are any. For the purposes of this manuscript, we are tentatively retaining the three separate species concepts until more material can be examined.

Range. Middle Miocene, EEP ( Table 1 ). Range poorly constrained.

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 4. Examples of specimen measurements discussed in the Systematic Paleontology section of this study.

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

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

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

FIGURE 9. Internal skeletal structure of Ceratocyrtis sp. C.

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

FIGURE 13. Chart illustrating the differences between Lophophaena gozui n. sp. (orange diamonds) and L. ushionii n. sp. (green squares), in terms of cephalis height and the ratio between thorax and cephalis width. L. gozui has a shorter average cephalis height (40 microns) compared to L. ushionii (average cephalis height = 54 microns). In addition, the thorax is proportionally wider compared to the cephalis in L. gozui (average ratio of thorax:cephalis width = 2.5). L. ushionii has a proportionally narrower thorax (average ratio of thorax: cephalis width = 1.5).

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.