radiolaria - rads_cat - Leptosphaera

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Leptosphaera

Citation: Leptosphaera Haeckel 1887

Type species: Leptosphaera hexagonalis Haeckel 1887 [designated by Campbell,1954, p.D62]

Astrosphaerida with two extracapsular cortical shells without by-spines, connected by long prismatic radial spines.

From the Greek leptosphaera = delicate sphere

The genus Leptosphaera, together with the three following genera, forms the very peculiar and typical small group of Sphaeroidea which we call the Diplosphaerida (with four genera and twenty-four species); their shell is composed of two concentric spheres as in the three foregoing genera; but whilst in these the inner shell is an intracapsular medullary shell and the outer an extracapsular cortical shell, in the
Diplosphaerida both shells are extracapsular or cortical shells, therefore the inner shell of the latter corresponds to the outer of the former. The inner spherical shell of all Diplosphaerida is composed of very delicate beams and large pores, which are either regular hexagonal or irregular polygonal (never roundish). From its surface arise a variable number (twenty to thirty) of stout long radial spines, which are invariabily longer than the shell diameter (often two to three times as 1ong or more), and of three-sided prismatic form, the three edges either smooth or serrate, often with three rows of lateral branches (commonly three to five branches in each row); the latter are invariably of the same form, concavely curved towards the spine, and decrease in size towards the distal end. From the three edges of each main spine in all Diplosphaerida, at equal distances from the centre, arise six very thin, thread-like lateral branches (a pair from each edge) and connect the spine in a tangential direction with all neighbouring spines. In this manner the polyhedral outer shell is formed, the meshes of which therefore are always very large and triangular. Sometimes each of these primary triangular meshes becomes filled up with a secondary network, either of regular quadrangular or of irregular polygonal secondary meshes. Besides the constant twenty to thirty large main spines, in the majority of Diplosphaerida bristle-shaped radial by-spines arise, either from the inner shell (Diplosphúra) or from the outer (Drymosphaera), or from both (Astrosphaera). They are absent only in Leptosphaera. Commonly the by-pines are simple, rarely forked or branched. The centra1 capsule in the Diplosphaerida is usually enclosed in the inner shell; often it completely fills up the latter, or drives out a caecal protuberance through each mesh; but these processes rarely unite outside. The average size of the Diplosphaerida, which are all pelagic organisms, is much larger than that of the other Haliommida.
[Description: The ""three foregoing genera"" refers to Haliomma, Heliosoma and Elatoma Haeckel, 1887a.
[Synonymized with Diplosphaera by Hollande and Enjumet, 1960, p.116]
Sub-genera described:

Leptosphaera (Leptosphaera) Haeckel 1887
Leptosphaera (Leptosphaerella) Haeckel 1887
Leptosphaera (Leptosphaeromma) Haeckel 1887

References:

Haeckel, E (1887). Report on the Radiolaria collected by H.M.S. Challenger during the years 1873-1876. Report on the Scientific Results of the Voyage of H.M.S. Challenger during the years 1873-1876. 18: 1-1803. gs O

				Leptosphaera arachnoides Jørgensen 1900
not figured				Leptosphaera ciliata Haeckel 1887
				Leptosphaera hexagonalis Haeckel 1887
				Leptosphaera minuta Popofsky 1912 = Leptosphaera minuta
not figured				Leptosphaera polygonalis Haeckel 1887
not figured				Leptosphaera reticulum Haeckel 1887
not figured				Leptosphaera serrata Haeckel 1887
not figured				Leptosphaera stellata Haeckel 1887

CATALOG OF ORIGINAL DESCRIPTIONS: Leptosphaera Haeckel 1887

Leptosphaera

References:

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