Eridotrypella exserta Morozova and Weis, 2002

Morozova, Iraida P., B. Weis, Olga & Racki, Grzegorz, 2002, Emergence and extinction of the Givetian to Frasnian bryozoan faunas in the Kostomłoty facies zone, Holy Cross Mountains, Poland, Acta Palaeontologica Polonica 47 (2), pp. 307-317 : 312-313

publication ID

https://doi.org/ 10.5281/zenodo.13304717

persistent identifier

https://treatment.plazi.org/id/03D3EC2D-1F3B-FFED-324A-F8BDD8B6DAAF

treatment provided by

Felipe

scientific name

Eridotrypella exserta Morozova and Weis
status

sp. nov.

Eridotrypella exserta Morozova and Weis , sp. nov.

Fig. 5D–H View Fig .

Holotype: PIN 4873 View Materials /20, Fig. 5D–H View Fig .

Type locality: Holy Cross Mts (Central Poland), Górno, Józefka Hill (set C of Racki 1993), middle Wietrznia Beds; Upper Devonian, middle Frasnian (? Pa. punctata Zone ).

Derivation of the name: From Latin exsertus, prominent.

Material.—Two colonies, 6 thin sections, PIN 4873/20, 4873/21.

Diagnosis.— E. exserta sp. nov. differs from the closest E. granulosa Morozova, 1955 in having largest autozooecial apertures (0.18–0.22 mm in diameter instead of 0.10–0.20 mm in E. granulosa ) and 5 apertures per 2 mm along colony and 6–6.5 diagonally instead of 8–9 apertures along colony and 10–11 diagonally in E. granulosa . Besides, the new species differs in having different size and form in the tangential section of the exilazooecial apertures forming small accumulations in maculae, and in having smaller capillaries (0.001 – 0.002 mm in diameter instead of 0.004 –0.005 mm in E. granulosa ).

Description.—Colony thin, ramose. Branches circular or slightly oval in transverse section, 1.7–2.4 mm in diameter. Exozone thickness 0.7–0.8 mm. Endozone very narrow, generally constituting one quarter or less of the colony diameter. Walls of the autozooecia in the endozone crenulated and gradually thickenning from beginning of endozone to outward. Thickness of the endozone walls 0.015 mm, that of the zooecial walls in exozone varies between 0.03 mm to 0.06 mm. Autozooecial chambers are with complete straight or curve diaphragms developed in the endozone (1–2 diaphragms) and exozone (4–6). Autozooecial apertures arranged in oblique rows. Their shape is slightly oval or irregularly circular. The length of the oval apertures ranges from 0.18 to 0.22 mm, and the width from 0.17 to 0.18 mm. Diameter of almost circular apertures is 0.20–0.22 mm. Distance between neighbouring apertural centers along colony 0.27–0.30 mm, diagonally 0.26–0.28 mm. There are about 5 apertures per 2 mm along colony and 6–6.5 diagonally. Exilazooecial apertures are irregularly distributed forming small accumulations in maculae ( Fig. 5E View Fig ), sometimes 1–2 exilazooecia meet near autozooecia. Outline of the exilazooecium apertures subcircular or oval near the colony surface, in deep tangential sections they become subangular. Diameters of the subcircular exilazooecial apertures 0.02–0.06 mm; the oval apertures are 0.02–0.03 mm long and 0.15 mm wide. Around each autozooecial and exilazooecial apertures stellatopores 5–6 are developed being about 0.02–0.03 mm in diameter. Numerous capillaries surround the stellatopores. Diameter of the capillaries 0.005 mm.

Remarks.— Eridotrypella exserta sp. nov. is similar only to Russian Eridotrypella spinulosa ( Morozova,1955) , described from the upper Frasnian of Kuzbass ( Morozova 1955: 784–785, fig. 1). Both species have delicate colonies with thick exozone and very narrow endozone and numerous diaphragms in autozooecia.

Occurrence.—Only the type locality.

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