Lithoporella minus Johnson, 1964
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publication ID |
https://doi.org/ 10.4202/app.00579.2018 |
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persistent identifier |
https://treatment.plazi.org/id/03B7C03D-FF85-FFC0-FC9E-FF1FFD7FF914 |
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treatment provided by |
Felipe |
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scientific name |
Lithoporella minus Johnson, 1964 |
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Lithoporella minus Johnson, 1964
Fig. 6A, B View Fig , Table 7, SOM: figs S2, S3.
Material.—Bi/tetrasporophytes ( Fig. 6A View Fig ) and gametophytes ( Fig. 6B View Fig ), NHM B1850/1 and NHM B1850/2 (thin section 5099), early Serravallian, Rohožník, Slovakia (Vienna Basin). Other examined specimens ( Table 7): NHM B1853 (thin section 381213162), late Serravallian, Wolfsthal, Austria (Vienna Basin); NHM B1851/1 (thin section 5111), early Serravallian, Rohožník, Slovakia (Vienna Basin); NHM B1848 (thin section ZTK3a) and NHM B1852 (thin section 711416), both early Serravallian, Devínska Kobyla, Slovakia (Vienna Basin); NHM B1854 (thin section 37913161), late Serravallian, Veľký Pesek, Slovakia (Danube Basin); NHM B1839/2 (thin section 184911151); early Langhian, Lopadea Veche, Romania (Transylvania Basin) and NHM B1833/4 (thin section 21510253), NHM B1834/2 (thin section 21510153), both early Serravallian, Maksymivka, Ukraine (Carpathian Foredeep).
Bi/tetrasporophytes from newly collected samples: thin sections VEGA 1849115651, VEGA 1849115551 from early Langhian, Lopadea Veche, Romania (Transylvania Basin); thin sections VEGA DKe, VEGA K3b, VEGA K3d, early Serravallian, Devínska Kobyla, Slovakia (Vienna Basin); thin section VEGA 371011452, early Serravallian, Vývrat, Slovakia (Vienna Basin); thin section VEGA 29711453, early Serravallian, Rohožník, Slovakia (Vienna Basin); thin sections VEGA 381213262, VEGA 381213362, VEGA 381213562, VEGA 381213662, VEGA 381213762, VEGA 381213862, all late Serravallian, Wolfsthal, Austria (Vienna Basin); thin section VEGA 7114261, late Serravallian, Devínska Kobyla, Slovakia (Vienna Basin); thin sections VEGA 37913261, VEGA 37913361, VEGA 37913661, all late Serravallian, Veľký Pesek, Slovakia (Danube Basin). Bi/ tetrasporangial plants from Schaleková’s collection (1973) including L. minus are: thin sections VEGA 5102, VEGA 2105, VEGA 5107, and VEGA 5223, early Serravallian, Rohožník, Slovakia (Vienna Basin).
Description.—Species was observed in samples from shallow water bioconstructions in Wolfsthal formed by L. minus , Titanoderma pustulatum , melobesioid alga and nubecularid foraminifers. Fragments of thalli are found in micrite sediment, together with ooids and benthic foraminifers. These fragments continue in growth and develop small and irregular rhodoliths less than 1 mm in D. Species from Rohožník grow on coral–coralline-algal–bryozoan reef, or
→ Fig. 5. Coralline alga Hydrolithon sp. 1 from early Serravallian, Maksymivka, Ukraine, Carpathian Foredeep. A. Bi/tetrasporophyte, NHM B1834/1 (thin section 21510153). A 1. Encrusting growth form with single slightly projecting bi/tetrasporangial conceptacle (arrow). A 2. Dimerous construction with flattened to square cells in primigenous filament (arrow); note the cells dimensions and shape that change from small cells in lower portion and much larger in upper portion of the single thallus. A 3. Cell fusions in adjacent cells of postigenous filaments (arrow). A 4. Arrow point to single layer of epithallial cells developed above meristematic cells that are elongated or of the same dimensions as cells immediately below them. A 5. Enlarged conceptacle from A 1. Bi/tetrasporangial conceptacle with roof filaments perpendicular to the chamber (arrow point to the pore canal and pore lining cells oriented perpendicular to the chamber as well). B. Male gametophyte, NHM B1833/2 (thin section 21510253); spermatangial conceptacle slightly projecting above the thallus surface. Note patches of enlarged cells (white arrows) and solitary trichocytes (black arrows). C. Carpogonial-carposporangial plant, NHM B1833/3 (thin section 21510253). C 1. Carpogonial conceptacle with large pore canal. Cells are projecting inside the pore canal (arrow). C 2. Carpogonial conceptacle (top) and carposporangial conceptacle (bottom). Arrow point to the portion of the conceptacle roof with preserved parallel orientation of the roof filaments with the chamber.
encrust other algae in soft bottom infra- to circalittoral settings ( Seneš and Ondrejčíková 1991). Lithoporella minus develops thin thallus with distinct conceptacles projecting above the thallus surface. Growth form is encrusting with applanate branches. Thallus is pseudoparenchymatous with dorsiventral internal organisation and dimerous construction. Specimen is entirely bistratose ( Fig. 6A View Fig 1 View Fig ). Multicellular postigenous filaments are situated near conceptacles only and on the places where thallus applanately branch. Cells of primigenous filaments are palisade in patches, rounded, square, flattened to rectangular ( Fig. 6A View Fig 2). Cells are 7–27 μm H (mean ± SD: 15 ± 5.8 μm) and 7–18 μm L (mean ± SD: 12 ± 3 μm) (n = 30). H/L ratio is 0.5–2.8. Postigenous filaments around conceptacles are of the same dimensions. Epithallial cells are flattened 2–6 μm L (mean ± SD: 3 ± 1.3 μm) and 4–12 μm D (mean ± SD: 6 ± 2.9 μm) ( Fig. 6A View Fig 3) n = 8). Trichocytes were not observed on bi/tetrasporophyte but occur solitary in gametangial–carposporangial plant.
Gametangial–carposporangial plant possesses uniporate conceptacles projecting above the thallus surface 109 μm with external diameter 224 μm ( Fig. 6B View Fig 1 View Fig ). Conceptacles are of peripheral to fertile area cells and cells of the pore canal projecting inside the canal ( Fig. 6B View Fig 1 View Fig ). Chamber is 122 μm D and 58 μm H. Pore measures 39 μm L and 21 μm W at the base. Dimensions of the conceptacle suggest carposporangial conceptacle. Solitary trichocytes are present in the thallus ( Fig. 6B View Fig ).
Bi/tetrasporangial conceptacle protrudes up to 109 μm above thallus surface and has 181 μm external diameter ( Fig. 6A View Fig 4). Chamber is 118 μm D and 58 μm H. Pore canal is cone shaped 34 μm L and 21 μm W. Single elongated cell lines the pore canal. Cells at the both sides of the cut are elongated and narrower than roof cells (SOM: figs S2, S3). Other specimen could have 1 pore canal cell in the roof formed by two celled filaments next to the pore canal (SOM: fig. S3). The roof filaments can consist of 1–3 cells.
Remarks.— Lithoporella minus has been found in the Langhian and Serravallian (middle Miocene). There is no example that such thallus was published till now from the middle Miocene of Slovakia or Czech Republic. But species known as Melobesia from the Paleocene and Eocene successions, figured in Schaleková´s (1962) correspond with Lithoporella minus ( Schaleková 1962: pl. 12: 23). Thus, Melobesia sp. from Sandberg and Rohožník with no figure or reference to thin sections ( Schaleková 1969: 100; Schaleková 1973: 218) would most likely represent observed species. Multiporate bi/tetrasporic conceptacles were not proved in any specimen. Species is known from early Langhian Carpathian Foredeep in Poland ( Studencki 1988b) and late Serravallian Transylvania Basin ( Bucur and Nicorici 1992). However, occurrences from Poland are sterile plants and identifications are based solely on palisade cells presence in entirely bistratose thalli. In contrary, fertile plant from Transylvania Basin known under the name Lithoporella aff. minus fits with characters of the observed specimens ( Table 7), but do not match with the type of L. minus ( Bucur and Nicorici 1992; Johnson 1964). Johnson (1964) mentioned, in conceptacles chambers description, only mean diameter. This value corresponds with the largest diameter measured in specimens from Central Parathethys. However, it is not known whether all specimens match with the minimum or it is out of the diameter interval of L. minus . Importantly, description of pore canal cells was not provided by Johnson (1964). Presence of palisade cells in primigenous filaments, dimerous thallus construction, lateral cell fusions and the type of bi/tetrasporic conceptacle development correspond with the diagnosis of the genus Lithoporella ( Turner and Woelkerling 1982) .
Geographical and stratigraphical range.—Eocene to middle Miocene of the Pacific and central Paratethys.
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