Ceratocyrtis, Butschli, 1882

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 : 31-32

Ceratocyrtis ? chimii n. sp.

Plate 11, Figs. 1A – 9 .

urn:lsid:zoobank.org:act:3C24AD7B-0B4E-480E-8681-9B1EDAE03FCA unknown plagonid group E sp 15, Trubovitz et al., 2020, supplementary data 7.

Diagnosis. Ceratocyrtis with a single large conical spine on the cephalis that is not an extension of the apical spine. Thorax is usually asymmetrical in outline, and has distinctive shoulders, which tend to be hyaline or have a reduced number of small pores.

Description. This species has a relatively large and well-developed cephalis compared to many other Ceratocyrtis species, but it is small compared to lophophaenids in general. The apical and ventral spines are similarly thin and short, sometimes barely protruding from the cephalis. The cephalis also exhibits a conical horn and the apex, the height and thickness of which varies considerably between specimens, but is always the most robust spine on the skeleton. There are sometimes delicate and thin, needle-like spines preserved throughout the surface of the cephalis and thorax as well. The thorax is asymmetrical in shape, with a more pronounced, sometimes nearly lobed shoulder on the dorsal side of the skeleton that varies in development between specimens. Pores are small throughout the shell, but tend to become smaller or have more hyaline spaces on the shoulders and on the cephalis. A set of large pores are present where the lateral spines intersect with the wall of the thorax, near the base of the cephalis. When adequately preserved, the thorax ends in a jagged termination that resembles short teeth. An axobate was observed in several specimens, however it often appears to be small or broken off.

Remarks. The overall skeletal proportions of this species best fit Ceratocyrtis out of all the other lophophaenid genera we observed, but the poorly-developed axobate and relatively large cephalis are uncharacteristic of this genus, so we only make a tentative genus assignment.

Material examined. 29 specimens from the Late Miocene samples 321-1337D-26H-3W, 142–144cm, 321- 1337D-23H- 6, 134–137cm, 321-1337A-21H-1, 33–35cm.

Holotype. Pl. 11, Figs. 5A–C ; sample 321-1337A-21H-1, 33–35cm; ECO-144; X28-2.

Paratypes. (1) Pl. 11, fig. 8; sample 321-1337A-21H-1, 33–35cm; ECO-144; W7-1. (2) Pl. 11, fig. 4; sample 321-1337A-21H-1, 33–35cm; ECO-144; D34-1. (3) Pl. 11, figs. 6A–B; sample 321-1337D-23H- 6, 134–137cm; ECO-145; G31-4. (4) Pl. 11, fig. 9; sample 321-1337D-23H- 6, 134–137cm; ECO-145; K6-1. (5) Pl. 11, fig. 7; sample 321-1337D-23H- 6, 134–137cm; ECO-145; O27-2. (6) Pl. 11, figs. 1A–C; sample 321-1337D-23H- 6, 134– 137cm; ECO-146; V40-3 . (7) Pl. 11, figs. 2A–C; sample 321-1337D-23H- 6, 134–137cm; ECO-146; O31-2. (8) Pl. 11, fig. 3; sample 321-1337D-23H- 6, 134–137cm; ECO-146; K30-1 .

Measurements. Height of cephalis 25–31 (28)μm; maximum width of thorax 67–83 (77)μm; length of thorax 48–66 (56)μm; height of horn on cephalis 13–43 (28)μm. Based on 15 specimens.

Etymology. Named for the mischievous mountain wilderness spirits in Japanese folklore, chimi.

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

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