New species of prunoid radiolarians from the Antarctic Neogene

Abstract

Abstract. Radiolarians with ‘prunoid’ morphologies (here defined as spumellarians with distinct external, generally ellipsoidal shells, usually bearing a pylome and having a lithelid, pylonid or spongy internal structure) are very common in polar Neogene sediments. Use of these taxa would improve resolution in Antarctic Neogene biostratigraphic and palaeoceanographic studies significantly, but the taxonomy of prunoids is poorly known. This paper reviews the existing literature of generic names commonly used for prunoids, mostly dating from the nineteenth century. With the exception of Larcopyle Dreyer 1889, these names are either assigned to other, non-prunoid groups or are considered to be nomina dubia. Fourteen species, subspecies or varieties – most of them new – of Larcopyle from Antarctic Neogene sediments are described, illustrated with full plates and stratigraphic range data are provided: L. augusti n. sp., L. buetschlii Dreyer, 1889, L. eccentricum n. sp., L. hayesi Chen, 1975 hayesi n. variety, L. h. irregularis n. variety, L. labryinthusa n. sp., L. nebulum n. sp., L. peregrinator n. sp., L. polyacantha (Campbell & Clark 1944) n. comb. polyacantha n. subsp., L. p. titan n. subsp., L. p. amplissima n. subsp., L. titan (Campbell & Clark, 1944) n. comb., L. pylomaticus (Riedel, 1958) n. comb. and L. weddellium n. sp.

New northwest Pacific radiolarian data as a tool to estimate past sea surface and intermediate water temperatures

“…Because L . weddellium was described from Weddell Sea materials, suggesting that this species is a cold‐water form [ Lazarus et al , ], our data are in agreement with previous studies.…”

Taxonomy and species diversity of Holocene pylonioid radiolarians from surface sediments of the northeastern Indian Ocean

“…This new species differs from "Prunopyle" longiseta (Dreyer, 1890) in that the latter has a more spherical outermost coverage shell and a larger bore pylome. This new species is different from Larcopyle peregrinator Lazarus, Faust, and Popova-Goll, 2005, in that the latter has a more robust outermost coverage shell with deeply depressed pores and numerous spinules around the mouth of the bore pylome. Dimensions.…”

“…Larcopyle eccentricanoides n. sp. is similar to Larcopyle eccentrica Lazarus, Faust and Popova-Goll, 2005, with a rectangular 2nd pseudoconcentric shell and a slender bore pylome. The former is distinguishable from the latter in that the latter has more pores in former's thick-walled outermost coverage shell, as well as sufficient space between the outermost coverage shell and the preceding pseudo-concentric shell.…”

“…However, these methods are not realistic for application in paleoceanographic studies in which thousands to millions of radiolarian specimens must be identified under transmitted light microscopy. This difficulty has further led to anguished application of superficially similar generic classifications such as Lithelius (Lithelioidea) and Larcopyle (Pylonioidea) for elliptical specimens with spirally concentric internal structures (Lazarus et al, 2005;Suzuki et al, 2009c). This difficulty has forced many studies to apply species complex names such as "Tetrapyle octacantha Müller group" (Itaki, 2009;Matsuzaki et al, 2015a;Motoyama et al, 2016) or "pyloniids" (Gupta, 2002(Gupta, , 2003.…”

New species of Neogene radiolarians from the Southern Ocean – part III

“…Although a more recent, inferred ontogeny-based taxonomical framework has been proposed (De Wever et al, 2001), some authors are in disagreement with it (e.g. Lazarus et al, 2005;Suzuki & Aita, 2011). Molecular-based classifications of radiolarians, which can perhaps better resolve higher-level relationships, are still in their infancy.…”