radiolaria - rads_cat - Amphiplecta satoshii

CATALOG OF ORIGINAL DESCRIPTIONS: Amphiplecta satoshii Renaudie & Lazarus 2015

This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.

Higher levels: rads_cat -> A -> Amphiplecta -> Amphiplecta satoshii
Other pages this level: A. acrostoma, A. amphistoma, A. callistoma, A. cylindrocephala, A. satoshii, A. tripleura

Amphiplecta satoshii

Citation: Amphiplecta satoshii Renaudie & Lazarus 2015
Rank: species
Type specimens: Pl. 5, figs 10–12B, 14A–15; Pl. 8, fig. 11
Type age (chronostrat): Occurrence. Rare from the Actinomma golownini to the lower Cycladophora spongothorax zones (Middle Miocene)
Type locality: Thirty-five specimens observed in samples from ODP Sites 748 and 751.
Type repository: MfN
Repository city: Berlin
Family (traditional): Plagiacanthidae

Current identification/main database link: Amphiplecta satoshii Renaudie & Lazarus 2015

Original Description

Dicyrtid with a long, apically-elongated cephalis (some specimens have a somewhat flattened apex; Pl. 5, figs 10–11) and a short, largely flaring thorax. Shell wall is smooth with randomly arranged, well-spaced, small, circular to elliptical pores. A large number of small thorns connected to one another are present at the apex of the cephalis including one broader thorn connected to spine a (see Pl. 5, fig. 11). Spine V is short, and can protrude at the collar stricture as a very short triangular horn (Pl. 5, fig. 10). In some specimens (such as in Pl. 5, fig. 11 and Pl. 8, fig. 11), apophyses j are strongly expressed and bifurcate, one upward, the other downward just before spine V connects to the wall. Spine a is fused to the dorsal part of the cephalic wall. An arch ad is well developed, thus creating a small shoulder. Spine d seems to bear some dents (Pl. 8, fig. 11) in addition to apophyse c which is thin and connects to the arch near its middle. ax is sometimes seen as a small dent of Mb. Spines ll and lr join Mb close to spines a and d (Pl. 8, fig. 11) and project subhorizontally, almost perpendicularly to the sagittal plan (hence the flaring of the upper thorax). They do not form wings. Arch Vl can be seen in some rare specimens as a thin rod. Although the cephalis and the thorax are separated by arches al and Vl, there are no visible furrows along those arches. Arch al is not distinct but may be embedded in the wall.


(Based on 4 specimens.) Height of the cephalis: 97–116 (105)

Named after Satoshi Funakawa, for his con- tribution to radiolarian research and particularly to plagiacanthid taxonomy

Extra details from original publication

remarks. It differs from Amphiplecta tripleura Funakawa, 1995bin the width/length ratio of its cephalis, in having less numerous, smaller pores as well as a smoother shell wall and in the dorsal shoulder being less developed but covered by the shell wall; fromA. cylindrocephala Dumitrica, 1973 in the thickness of its wall, the shape of its cephalis and in having less numerous, smaller pores. Contrary to what is seen in A. tripleura and A. acrostoma Haeckel, 1887 (Petrushevskaya, 1971; Funakawa, 1994, 1995b), arch dl(or d-al according to Funakawa 1995b) is not recognizable in our species, and arch al is not distinguishable from the rest of the wall. This renders the genus assignment questionable; however, the fact that arch ad is clearly expressed as a bump external to the rest of the cephalis and the overall shape of the cephalis seems to indicate a close relationship of A.? satoshii with those two species.

Amphiplecta? satoshii also differs from Lophophaena galeataehrenberg, 1874 (see also Ogane et al., 2009, pl. 79, fig. 1a–c) and L. capito ehrenberg, 1874 (see also Ogane et al., 2009, pl. 79, fig. 2a–c) in its elongated cephalis with a flattened top, the presence of a cluster of apical spines instead of just a unique spine and, more importantly, in its inner cephalic structure: L. galeata seems, based on the Ogane et al. (2009) pictures, to have well-expressed arches ap reminiscent of the ones in Lithomelissa ehrenbergi Bütschli, 1882 (see more in the Description and Remarks section of Lithomelissa celsagula n. sp.).

Editors' Notes


Renaudie, J. & Lazarus, D. (2015). New species of Neogene radiolarians from the Southern Ocean - Part III. Journal of Micropalaeontology. 34: 181-209. gs


Amphiplecta satoshii compiled by the radiolaria@mikrotax project team viewed: 15-8-2022

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