Lophophaena leshii, 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 : 62

Lophophaena leshii n. sp.

Plate 24, Figs. 3A – 9 .

urn:lsid:zoobank.org:pub:A9179C79-EE43-44E4-8723-919505500049

Acanthocorys variabilis Popofsky, 1913 , text-fig. 81, non figs. 71–80.

? Acanthocorys cf. variabilis Popofsky, Takahashi, 1991 , pl. 25, fig. 1.

Lophophaena cf. buetschlii sp. 2, Trubovitz et al., 2020, supplementary data 7.

Diagnosis. Lophophaena with a very elongated cephalis that thins or is left open at the top, and a thorax only slightly wider than the cephalis with three long, conical appendages extending from the dorsal and lateral spines.

Description. This species has a very long and narrow cephalis, that becomes more thinly-silicified and increasingly hyaline, with fewer and smaller pores, towards the top. The apical spine runs along the wall of the cephalis, and extends upward from the inflection point where the cephalis begins to round toward the apex. The apical horn is conical and relatively thin. A short, needle-like ventral spine is present in the neck area, which is relatively compressed for a cephalis of this height. The thorax is slightly wider than the cephalis and has pores similar in size to those at the base of the cephalis. Near the top of the thorax, the lateral spines protrude as long, prominent appendages that are subhorizontal. The dorsal spine extends at a more acute downward angle, but matches the lateral spines in thickness and length.

Remarks. This species appears to be related to L. buetschlii (Haeckel) Petrushevskaya, 1971 (Pl. 24, Figs. 1A – 2B ) because both species have similar segment proportions, and an elongated cephalis that may be left open at the top. However, Lophophaena leshii n. sp. differs in that it has strong, conical thoracic appendages, usually with pointed tips, that are at least as long as the apical spine, and usually better-developed. These spines usually extend cleanly from the thorax, or with a small amount of buttressing, without the tendency to form “wings” of skeletal lattice as they often do in L. buetschlii . The cephalis of this species also has less variation in length than L. buetschlii . This species appears to have been first illustrated by Popofsky (1913) as Acanthocorys variabilis (text-fig. 81, non text-figs. 71–80). However, Petrushevskaya (1971) did not consider this to be part of her emended species concept of Lophophaena variabilis , and did not reassign Popofsky’s specimen in text-fig. 81 to a different name. It also appears that Takahashi (1991) may have illustrated this species under the name Acanthocorys cf. variabilis (Popofsky) , but the image quality in that publication is too poor for us to be certain.

Material examined. 24 specimens observed from sample 321-1337D-23H- 6, 134–137cm (Late Miocene).

Holotype. Pl. 24, Fig. 4 ; sample 321-1337D-23H- 6, 134– 137cm ; ECO-147; D9-2.

Paratypes. (1) Pl. 24, figs. 3A–C; sample 321-1337D-23H- 6, 134–137cm; ECO-145; H34-2. (2) Pl. 24, figs. 5A–B; sample 321-1337D-23H- 6, 134–137cm; ECO-147; K27-2. (3) Pl. 24, figs. 7A-B; sample 321-1337D-23H- 6, 134–137cm; ECO-145; H5-4. (4) Pl. 24, fig. 8; sample 321-1337D-23H- 6, 134–137cm; ECO-145; L7-3. (5) Pl. 24, fig. 9; sample 321-1337D-23H- 6, 134–137cm; ECO-145; P15-2. (6) Pl. 24, figs. 6A–B; sample 321-1337D-23H- 6, 134–137cm; ECO-145; O14-4. (7) [not figured] sample 321-1337D-23H- 6, 134–137cm; ECO-146; Q37-1. (8) [not figured] sample 321-1337D-23H- 6, 134–137cm; ECO-146; J9-3.

Measurements. Cephalis height 47–56 (51)μm; cephalis width at its center 22–27 (25)μm; width at shoulder area at top of thorax 30–40 (33)μm; length that lateral/dorsal spines protrude from the thorax 23–41 (32)μm. Based on 13 specimens.

Etymology. Named for the forest spirit of Slavic folklore, the Leshi.

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

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