Pelagomanes ibburi, 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 : 80-81

Pelagomanes ibburi n. sp.

Plate 41, Figs. 1A – 6B .

urn:lsid:zoobank.org:act:3F89A23A-6C54-4E59-8FA0-71B62A21F316

Lithomelissa kozoi cf sp 1, Trubovitz et al. 2020, supplementary data 7.

Diagnosis. Pelagomanes with a cephalis that ranges from having few, small pores to being entirely hyaline, has a relatively weak hooklike apical horn, and an elongated thorax with very strong shoulders at the top and three feet in addition to small teeth at the base.

Description. The cephalis of this species has small pores and is often hyaline (i.e., figs. 1 and 2). The apical horn extends from the dorsal side of the cephalis before reaching the apex, and is slightly curved at its base. The thorax is approximately twice the length of the cephalis, and slightly wider than it. Pores on the thorax get larger toward the base, and have the tendency to become more elongated in shape. Prominent shoulders exhibit at the top of the thorax, and the furrows between them extend downwards as ribs along the thorax and finally as bladed feet at the base of the skeleton. The base of the thorax may be enclosed in some specimens (i.e., fig. 3), and fully-preserved individuals show small teeth at the base of the thorax between the three feet.

Remarks. This species differs from Pelagomanes kozoi Renaudie and Lazarus, 2013a (Pl. 39, Figs. 1–6 ) in that the shoulders are usually stronger, and the teeth at the base of the thorax are shorter and have more contrast with the three feet. In addition, the thorax of this species tends to be longer than in P. kozoi , and the cephalis is often more hyaline. This species differs from Pseudodictyophimus gracilipes in that the thorax is narrower and more elongated. The apical and ventral horns show variable development, but are never as strong as those of P. thaumasia (Pl. 39, Figs. 10A –11), P. morawanensis (Pl. 40, Figs. 4A – 6 , 9 , 11–12), or P. tekopua (Pl. 40, Fig. 13 ).

Material examined. 78 specimens observed from samples 321-1337A-35X-1, 106–108cm (Middle Miocene), 321-1337A-31X-6, 4–6cm (Middle Miocene), 321-1337D-30H-3, 103–104cm (Middle Miocene), 321-1337D-26H- 3, 142–144cm (Late Miocene), 321-1337D-23H- 6, 134–137cm (Late Miocene), 321-1337A-18H-6, 77–80cm (Late Miocene), 321-1337A-16H- 6, 121–124cm (Late Miocene), 321-1337A-14H-7, 39–42cm (Late Miocene), 321-1337A-12H-5, 23–26cm (Late Miocene), 321-1337A-10H-2, 91–94cm (Early Pliocene), 321-1337A-7H- 6, 104–107cm (Early Pliocene), 321-1337A-6H-3, 29–32cm (Late Pliocene), 321-1337A-4H- 6, 115–118cm (Early Pleistocene), 321-1337A-4H-2, 16–19cm (Middle Pleistocene), 321-1337A-3H- 2, 103–106cm (Middle Pleistocene), 321-1337A-2H-3, 76–79cm (Late Pleistocene), and 321-1337D-1H-1, 0–3cm (Recent).

Holotype. Pl. 41, Figs. 2A–B ; sample 321-1337A-16H- 6, 121– 124cm ; ECO-141; Z12-4.

Paratypes. (1) Pl. 41, figs. 1A–B; sample 321-1337A-16H- 6, 121–124cm ; ECO-143; K12-3. (2) Pl. 41, figs. 4A–B; sample 321-1337D-23H- 6, 134–137cm ; ECO-145; N15-1. (3) Pl. 41, figs. 3A–B; sample 321-1337D-23H- 6, 134–137cm ; ECO-145; G17-2. (4) Pl. 41, figs. 6A–B; sample 321-1337A-14H-7 , 39–42cm; ECO-138; V9-2. (5) Pl. 41, figs. 5A–B; sample 321-1337A-16H- 6, 121–124cm ; ECO-143; J18-2 .

Measurements. Cephalis height 30–37 (34)μm, cephalis width 26–31 (29)μm, thorax length (not including feet) 45–59 (49)μm, width at shoulders 38–47 (42)μm. Based on 8 specimens.

Etymology. Named for ibbur in Jewish folklore, a type of benevolent spirit possession intended to help people succeed.

Range. Middle Miocene—Recent, 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 4. Examples of specimen measurements discussed in the Systematic Paleontology section of this study.

FIGURE 5. Internal skeletal structure of Amphiplecta acrostoma Haeckel, 1887.

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

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).