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Salpingoporella scopuliformis n. sp. (Dasycladales, Green Algae) from the Middle Triassic of Croatia

The new Dasycladalen species Salpingoporella scopuliformis n. sp. was indentified in the Pelsonian (Anisian, Middle Triassic) limestones from Belski dol quarry (Ivanščica Mt., NW Croatia). The new alga is characterised by a cylindrical thallus with a very narrow central cavity. The thallus is often disintegrated into fragments. The branches swell above the thin basal part, and have slightly increasing (in some cases uniform) diameter along the most of their length. At the distal part they slightly expand (phloiophorous type), and probably touch each other forming an irregular cortex. Branches are arranged into close whorls and placed obliquely to the longitudinal axis. The euspondyl arrangement is well visible in the proximal part of the branches, but in the distal part the arrangement is more or less irregular and resembles a broom (lat. scopulae = small broom ; forma = form, shape). The euspondyl arrangement of the phloiophorous branches give rise to assigning the new alga to the genus Salpingoporella. The authors are aware that this genus includes a very wide range of forms. Other Salpingoporella species are easily distinguishable from the new species in having a relatively wider central cavity. The majority of them have more pronounced distal swelling of the branches. Regarding Triassic species of theis genus, Carnian S. humulis (BYSTRICKY) is smaller and has convex and thinner branches, while Ladinian-Norian S. spectabilis (BYSTRICKY), Carnian S. sturi (BYSTRICKY), and Carnian S. ?tibetica FLEL & MU have branches perpendicular to the longitudinal axis. The new species resemble Euteutloporella peniculiformis (OTT), which also has a very narrow central cavity and often disintegrates into fragments, but has very thin and mostly curved trichophorous branches. Macroporella alpina PIA has somewhat similar external morphology and distally expanded branches, but with the wider central cavity, and the aspondyl to mesospondyl arrangement of the branches. At the type-locality Salpingoporella scopuliformis n. sp. was found together with other dasycladaleans: Oligoporella cornuta (= O. pilosa var. varicans), Oligoporella pilosa, O. varicans (= Ph. varicans), Physoporella pauciforata var. pauciforata, Ph. pauciforata var. sulcata, Euteutloporella peniculiformis, and foraminifera Meandrospira dinarica. This assemblage clearly determines the Pelsonian age. The palaeoenvironment can be interpreted as a back-reef. Besides the type-locality, the new species has been found at several localities in the Croatian Outer Dinarides together with dasycladaleans typical for the Pelsonian-Lower Illyrian range: Oligoporella- Physoporella species, Diplopora proba, Teutloporella tabulata, Macroporella alpina and Euteutloporella peniculiformis.

Dasycladales ; green algae ; Triassic ; Croatia

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