Primorella nitida 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 : 314-315

publication ID

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

persistent identifier

https://treatment.plazi.org/id/03D3EC2D-1F39-FFE3-324A-F957D805D93D

treatment provided by

Felipe

scientific name

Primorella nitida Morozova and Weis
status

sp. nov.

Primorella nitida Morozova and Weis , sp. nov.

Fig. 6D–G View Fig .

Holotype: PIN 4873 View Materials /11, Fig. 6D–F View Fig .

Type locality: Holy Cross Mts (Central Poland), Górno, Józefka Hill (set A of Racki 1993), Laskowa Góra Beds; Middle Devonian, upper Givetian (?Middle Po. varcus to K. disparilis zones).

Derivation of the name: From Latin nitidus, elegant, fine.

Material.—Five colonies, 15 thin sections, PIN 4873/11– 4873/15.

Diagnosis.—This species is similar to stratigraphically younger Primorella indigena sp. nov. in most characters, but distinctly differs in the smaller diameter of colony (0.9–1 mm instead 1.7–2 mm instead of in P. indigena ) and in thinner zooecial walls in the exozone. Autozooecial apertures of P. nitida are largely oval (instead of subcircular in P. indigena ), whilst stellatopores are more numerous (7–12 around the apertures, instead of 6–9).

Description.—Colony thin, ramose. Diameter of branches 0.9–1 mm; thickness of exozone 0.26–0.35 mm, width of endozone about 0.40–0.45 mm. The spirally budding autozooecia gently bend outward from the central axis. The autozooecial chambers are long and tubular, with 2–4 diaphragms in each autozooecium. Diaphragms complete, straight or concave. Zooecial walls in the endozone 0.007– 0.01 mm thick, the thickness of zooecial walls in the exozone 0.11–0.13 mm. Apertures arranged in regular longitudinal series and cross diagonal rows. Aperture outlines oval, averaging 0.17–0.20 mm in length, and 0.08–0.10 mm in width. In 2 mm there are 6–6.5 apertures along the colony and 8 diagonally across the colony. Distance between neighbouring apertural centers along colony 0.35–0.45 mm, diagonally 0.20–0.24 mm. Numerous stellatopores (actinotostyles of the American authors [ Blake 1983]) and small pores surround the apertures and pierce all walls in the exozone. Diameter of stellatopores 0.01–0.03 mm. Seven to twelve stellatopores developed as a chain around each autozooecial aperture. Diameter of capillaries 0.003 –0.004 mm.

Occurrence.—Only the type locality.

Primorella indigena Morozova and Weis , sp. nov. Fig. 6H–J View Fig .

Holotype: PIN 4873 View Materials /16, Fig. 6H–J 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 indigenus, local.

Material.—Three colonies, 8 thin sections, PIN 4873/16– 4873/18.

Diagnosis.—This Frasnian species differs from P. nitida sp. nov. in its larger measurements, namely in the diameter of colony (1.7–2 mm in P. indigena , 0.9–1 mm in P. nitida ), and also in thicker zooecial walls in the exozone. Most of autozooecial apertures of P. indigena are subcircular (oval in P. nitida ) and arranged in irregular longitudinal series. The stellatopores are not so abundant (6–9 around the apertures, instead of 7–12).

Description.—Colony thin, ramose. Diameter of branches 1.70–2 mm, thickness of exozone 0.50–0.52 mm, width of endozone 0.65–0.70 mm. Autozooecial tubes curve gently from mesotheca outward at an angle of about 45°. Autozooecial chambers are with 3–5 diaphragms in the exozone. Diaphragms complete, sometimes concave. Zooecial walls are thin in endozone (0.01 mm) becoming rapidly thickened in exozone (0.20–0.25 mm). Aperture outline subcircular, rarely oval. Diameter of circular apertures 0.10–0.12 mm. The length of oval apertures 0.13–0.14 mm, the width— 0.10–0.11 mm. In 2 mm there are 5 apertures along colony and 8 diagonally. Distance between neighbouring apertural centers along colony 0.4–0.5 mm, diagonally 0.25–0.3 mm. Six to nine stellatopores with a diameter of about 0.01–0.03 mm are present around each autozooecial aperture. Numerous capillaries surround the stellatopores and pierce all walls in exozone. Diameter of capillaries 0.005 mm.

Occurrence.—Only the type locality.

Rhombopora cf. dispersa Bigey, 1988 .—Poorly−preserved ramose zoaria, very close to the French species from middle Frasnian Ferques Formation ( Bigey 1988a, b), occur in the uppermost Givetian at Chęciny (Zamkowa Góra, lower Chęciny Beds), as well as in middle Frasnian strata at Górno (Wietrznia Beds).

Saffordotaxis sp. —Representatives of this rhabdomesid genus are found exclusively in the upper Givetian bryozoan association from Górno (Laskowa Góra Beds).

Acanthoclema cf. distilum Bigey, 1988 .—Zoaria resembling A. distilum from the Blacourt Formation at Ferques

( Bigey 1988a) occur in the upper Givetian strata at Górno (Laskowa Góra Beds).

Orthopora sp. —This rhabdomesid genus is rarely represented in diverse upper Givetian bryozoan association from Górno (Laskowa Góra Beds).

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