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Liriospyris mutuaria
Goll, 1968
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Description - Add description
Liriospyris mutuaria
Diagnosis.—A species of Liriospyris characterized by a lattice bar that is joined to the sagittal ring at the proximal end of the vertical spine, a lattice shell that does not surround the sagittal ring in the sagittal or horizontal planes, and the absence of basal spines.
Etymology of name.—The trivial name is derived from the Latin word mutuarius, meaning mutual, and refers to the common point of connection with the sagittal ring of one of the lattice bars and the vertical spine.
Description.—Sagittal ring subcircular; 55 to 68µ high; 53 to 68µ thick; joined directly to front, apex, and back of lattice shell. Vertical spine very short, projecting from approximate midpoint of sagittal ring; no frontal or axial spines. Most specimens lack an apical spine; other skeletons have very short apical spine. Some specimens have primary-lateral spines and no connector bars, whereas other forms have primary-lateral bars joined to basal ring. Basal ring subpolygonal; 56 to 78µ wide; 37 to 56µ thick; joined directly to front and back of sagittal ring; encloses two or four basal pores. No lattice or basal spines. Lattice shell 68 to 130pt wide; not constricted sagittally; does not extend below basal ring. In most specimens, lattice shell smooth; a few skeletons have small tubercles on lattice bars. Lattice bars massive, polygonal in cross section, and frame subcircular lattice pores 3 to 37[x in diameter; number of lattice bars joined to basal ring variable. Four lattice bars joined to sagittal ring; one junction at proximal end of vertical spine. In some specimens, borders of lattice pores serrate. Five pairs of sagittal-lattice pores; no vertical, frontal, or sternal pores. Remarks.—Representatives of Liriospyris mutuaria n. sp. differ from those of L. elevata n. sp. in having four lattice bars that are joined to the sagittal ring; from specimens of L. globosa n. sp. in having a sagittal ring that is joined directly to the front and back of the lattice shell; and from skeletons of Tholospyris anthophora (Haeckel) in having a lattice bar that is joined to the sagittal ring at the proximal end of the vertical spine. Unlike specimens of L. mutuaria, those of the type-species of Liriospyris, L. Clathrata, have five lattice bars that are joined to the sagittal ring; a sternal bar, a sternal pore, and a tertiary-lateral bars.
Occurrence.—Liriospyris mutuaria is represented in all the samples between JYN V 20P, 450-452 cm. (lower lower Miocene) and MSN 132P, 350-352 cm. (middle Miocene), and in six of the 18 younger samples.
Holotype.—USNM 650373, from core sample AMPH 109P, 435-440 cm. (upper lower Miocene). | | Goll 1968 |
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