Lophophaena casperi, 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 : 54

Lophophaena casperi n. sp.

Plate 28, Figs. 1A – 9B .

urn:lsid:zoobank.org:act:F96F8032-1408-4E90-B84F-CC30D80A16D0

? Tripodocorys sp. A ., Sugiyama, 1994, pl. 5, figs. 3a–d.

unknown plagonid group C sp 28, Trubovitz et al., 2020, supplementary data 7.

Diagnosis. Lophophaena with an hourglass shape in outline, exhibiting many thin spines around the cephalis and the shoulders of the thorax.

Description. This species has a high, balloon- shaped cephalis that reaches its widest point about ⅔ of the way up. From the circumference of this wide point, many thin spines extend upward from the cephalis. Pores on the cephalis are small and round. The neck area is proportionally narrow, and includes several short, thin spines in addition to the horizontally-orientated ventral spine. The thorax flares widely at the shoulders, contributing to the skeleton’s overall hourglass shape. When well-preserved, many thin spines extend down and outward from the widest point of the shoulders. Below the shoulders, the thorax wall tends to become thinner and have smaller, more irregular pores. The base of the thorax is smooth, lacking teeth at the termination.

Remarks. This species shows a relatively high amount of size variation, but the shell shape and proportions are consistent. It differs from Lophophaena rusalkae n. sp. (Pl. 29, Figs. 1A – 6 ) in its larger overall size, and more pronounced hourglass shape, with a long and narrow neck, and high, inflated cephalis. Figure 12 illustrates how the cephalis dimensions are different between these two species, which can appear similar at first glance.

Material examined. 85 specimens observed from Late Miocene samples 321-1337A-21H-1, 33–35cm, 321- 1337A-18H-6, 77–80cm, 321-1337A-16H- 6, 121–124cm, and 321-1337A-14H-7, 39–42cm.

Holotype. Pl. 28, figs. 1A–B; sample 321-1337A-21H-1 , 33–35cm; ECO-144; G3-1 .

Paratypes. (1) Pl. 28, figs. 4A–B; sample 321-1337A-21H-1, 33–35cm; ECO-144; S16-2. (2) Pl. 28, fig. 2; sample 321-1337A-14H-7, 39–42cm; ECO-139; W39-4. (3) Pl. 28, figs. 8A–B; sample 321-1337A-14H-7, 39– 42cm; ECO-138; Q30-1. (4) Pl. 28, figs. 7A–B; sample 321-1337A-16H- 6, 121–124cm; ECO-141; W22-1. (5) Pl. 28, figs. 5A–B; sample 321-1337A-16H- 6, 121–124cm; ECO-142; M17-1. (6) Pl. 28, fig. 3; sample 321-1337A-16H- 6, 121–124cm; ECO-141; J15-4. (7) Pl. 28, figs. 6A–B; sample 321-1337A-16H- 6, 121–124cm; ECO-141; H39-4. (8) [not figured] sample 321-1337A-16H- 6, 121–124cm; ECO-141; C2-2.

Measurements. Height of cephalis 44–58 (52)μm; width of cephalis 30–41 (38)μm; width at neck 23–33 (29)μm; width at shoulders 42–52 (48)μm. Based on 16 specimens.

Etymology. Named for Casper the friendly ghost, a mid-century American cartoon character.

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

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

FIGURE 12. Chart illustrating the different cephalis dimensions of Lophophaena casperi n. sp. (blue squares) and L. rusalkae n. sp. (red triangles). L. rusalkae has a cephalis height ranging from 34-40 microns, and an average cephalis width:neck ratio of 1. By contrast, L. casperi has a higher cephalis, ranging from 44- 58 microns, and a cephalis width:neck ratio averaging 1.3. The specimen with a cephalis width:neck ratio of 1.7, which is visually the outlier on this chart, has a particularly narrow neck (23 microns), but a cephalis of typical width for this species (40 microns).