Amphiplecta kikimorae, 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 : 14-15

Amphiplecta kikimorae n. sp.

Plate 2, Figs. 1A – 5B .

urn:lsid:zoobank.org:act:EAE8E650-339C-4F65-9EC1-FE177F10735C

Diagnosis. Broad, elongated, inverted-conical cephalis that is widest and fully-enclosed at the top; thorax flares widely, has three ribs, and a distinct constriction or termination at the base.

Description. Amphiplecta with a broad, conical cephalis that is enclosed and flat on the top, is surrounded by a crown of short spines, and reaches its widest point at the top. The apical horn is strong and three-bladed. The AL arches and the AD arch are well defined, as in other Amphiplecta species. The thorax flares widely, and has a distinct termination or constriction where the dorsal and lateral ribs penetrate the thorax. Some specimens show additional skeletal development below the constriction (i.e., figs 1 and 3), while others appear to terminate the shell at this point (i.e., fig. 2).

Remarks. This species differs from Lampromitra schultzei (Haeckel) Takahashi, 1991 in that its cephalis is significantly larger and more angular. It differs from Amphiplecta acrostoma Haeckel (pl. 1, figs. 1A–2) in that its cephalis is wider and fully enclosed. It differs from Amphiplecta cylindrocephala Dumitrica, 1973 in that it has a broader and enclosed cephalis, but has a similar crown of short thorns around the top. The thorax is relatively short compared to other Amphiplecta species. The relatively broad, enclosed nature of the cephalis and constricted thorax produce some uncertainty as to the genus designation. However, the structure of the internal skeleton, the continuity of the cephalis and thorax without a clear neck region, as well as the external shape of the shell resemble other species assigned to Amphiplecta more than any other genera we are aware of.

Material examined. 7 specimens from sample 321-1337A-7H- 6, 104–107cm (Early Pliocene).

Holotype. Pl. 2, figs. 1A–C; sample 321-1337A-7H- 6, 104– 107cm ; ECO-134; L4-1.

Paratypes. (1) Pl. 2, figs. 2A–B; sample 321-1337A-7H- 6, 104– 107cm ; ECO-134; S32-2. (2) Pl. 2, figs. 3A–B; sample 321-1337A-7H- 6, 104– 107cm ; ECO-135; K5-1. (3) Pl. 2, fig. 4; sample 321-1337A-7H- 6, 104– 107cm ; ECO-135; R6-2. (4) Pl. 2, figs. 5A–B; sample 321-1337A-7H- 6, 104– 107cm ; ECO-134-Q17-1. (5) [not figured] sample 321-1337A-7H- 6, 104– 107cm ; ECO-135; U31-4 .

Measurements. Height of cephalis 37–43 (40)μm; maximum width of cephalis 39–48 (44)μm; maximum width of thorax 59–68 (64)μm; length of thorax 26–36 (32)μm. Based on 6 specimens.

Etymology. Named for the female house spirit in Slavic folklore, Kikimora.

Range. Early Pliocene in the EEP, as far as known ( 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.