Stellatoides muellertchensis, Ernst & Taylor & Bohatý, 2014

Ernst, Andrej, Taylor, Paul D. & Bohatý, Jan, 2014, A new Middle Devonian cystoporate bryozoan from Germany containing a new symbiont bioclaustration, Acta Palaeontologica Polonica 59 (1), pp. 173-183 : 176-177

Stellatoides muellertchensis gen. et sp. nov.

Figs. 3–5 .

Etymology: Named after the type locality Müllertchen Quarry.

Type material: Holotype: SMF 21.108 ( Fig. 4A ), 4 thin sections . Paratypes: SMF 21.109 - SMF 21.116 (19 thin sections from 4 colonies and 5 unprepared colonies).

Type locality: Üxheim-Ahütte , abandoned Müllertchen Quarry , Hillersheim syncline, Eifel, western Rhenish Massif (geological map sheet 5606 Üxheim; 50°21’, 6°46’) .

Type horizon: Set 2 “Wurmweide”, Olifant Member , Müllert Subformation ( Ahbach Formation , lowermost Lower Givetian, Middle Devonian; Polygnathus hemiansatus Conodont Biozone ) .

Other material.—Eight cleaned colonies in the private collection of Robert Leunissen (Nideggen-Wollersheim, Germany).

Diagnosis.—As for monotypic genus.

Description.—Colonies lamellar, often with multiple overgrowths ( Fig. 4B ), freely growing or encrusting ephemeral substrates and producing hollow ramose, goblet-shaped colonies ( Fig. 3A ). Encrusting sheets 0.5–2.2 mm in thickness, multilayered colonies reaching up to 4.3 mm thick. Maculae elongate ( Fig. 3B ), 2.8–12.0 mm long by 1.0– 2.9 mm wide, spaced 6.4–13.8 mm from centre to centre, stellate, with depressed centres comprising vesicular tissue ( Fig. 4A 2 ); shorter and wider at the base of ramose colonies, becoming longer and narrower in distal parts of goblet-shaped colonies.

Autozooecia cylindrical ( Fig. 4A 1 ), growing from thin epitheca, bending sharply towards colony surface at their bases. Apertures circular to oval. Lunaria triangular, consisting of hyaline material, directed towards the nearest macula. Basal diaphragms rare, thin, horizontal or inclined. Vesicles medium to large in size ( Fig. 4A 3 ), separating autozooecia in 1–2 rows, 5–9 surrounding each autozooecial aperture, polygonal in tangential section, box-like to hemispherical, with plane or concave roofs, consisting of granular skeleton. Single acanthostyle occurring at centre of each vesicle roof ( Fig. 4A 5 ), with narrow laminated sheath and distinct hyaline core, 0.020 –0.035 mm in diameter. Autozooecial walls granular, 0.010 –0.020 mm thick.

Stratigraphic and geographic range.—As for genus.

Figures

Fig. 3. Fistuliporid bryozoan Stellatoides muellertchensis gen. et sp. nov., Middle Devonian (Lower Givetian, Ahbach Formation) of the abandoned “Müllertchen Quarry” (Hillesheim Syncline, Eifel, Rhenish Massif, northwestern Rhineland-Palatinate, Germany). A. Paratype SMF 21.115, goblet-shaped colony, side view. B. Paratype SMF 21.110, fragment of goblet-shaped colony showing maculae.

Fig. 4. Fistuliporid bryozoan Stellatoides muellertchensis gen. et sp. nov., Middle Devonian (Lower Givetian) of the Rhenish Massif, north-western Rhineland-Palatinate, Germany. A. Holotype SMF 21.108, transverse section showing autozooecial chambers and vesicular skeleton (A), tangential sec1 tions showing autozooecial apertures with lunaria and vesicles (A 2 –A 5). B. Paratype SMF 21.113, longitudinal section showing multilayered secondary overgrowths.

Fig. 5. Cylindrical embedment trace (bioclaustration) Chaetosalpinx tapanilai ichnosp. nov., Middle Devonian (Lower Givetian) of the Rhenish Massif, north-western Rhineland-Palatinate, Germany. A. Paratype SMF 21.115, colony surface of fistuliporid bryozoan Stellatoides muellertchensis gen. et sp. nov. showing tubes of C. tapanilai. B. Paratype SMF 21.122, tangential section of tubes of C. tapanilai. C. Holotype SMF 21.118, longitudinal section of a tube.

Fig. 2. Lowermost Lower Givetian stratigraphy of the “Type Eifelian Profile” sensu Struve (1982); light grey: biostratigraphic distribution of fistuliporid bryozoan Stellatoides muellertchensis gen. et sp. nov.; dark grey: maximum distribution.

Fig. 1. Map showing location of the abandoned Müllertchen Quarry within the Hillesheim Syncline. Geological overview of the Rhenish Massif (A), showing the studied area (taken from Bohatý et al. 2012; modified from Korn 2008 after Walter 1995) and detailed view of the Eifel Synclines (B) with the fossil locality 1 (modified after Struve 1996c).