Trieres mobiliensis (Bailey) Ashworth and E.C. Theriot

Sims, Pat A., Williams, David M. & Ashworth, Matt, 2018, Examination of type specimens for the genera Odontella and Zygoceros (Bacillariophyceae) with evidence for the new family Odontellaceae and a description of three new genera, Phytotaxa 382 (1), pp. 1-56 : 6

Trieres mobiliensis (Bailey) Ashworth and E.C. Theriot ( Figs 1–7 )

Basionym:— Odontella mobiliensis Bailey (1851: 6) = ?? Zygoceros mobiliensis Bailey (1851: 40 , pl. 2, figs 34, 35)

Synonyms:— Denticella mobiliensis (Bailey) Ehrenberg (1853: 256) Zygoceros mobiliensis (Bailey) Ralfs in Pritchard (1861: 850, pl. 6, fig. 11) Biddulphia mobiliensis (Bailey) Grunow in Van Heurck (1882: pl. 101, figs 4–6) Odontella mobiliensis (Bailey) Grunow (1884: 58) , invalid

Type:— “… Mobile Bay…”, “Savannah, GA [Georgia]”. In the text, Bailey (1851: 4, footnote) writes that those species marked with a star are new and will be described later. Odontella mobilensis Bailey (1851: 6) is so marked but is described later under the name ‘ Zygozeros [sic] ( Denticella ?) ’ mobilensis instead of Odontella ( Bailey 1851: 40) . In the description of ‘ Zygozeros [sic] ( Denticella ?) ’ mobilensis Bailey writes “…from Mobile Bay, and subsequently I have found it at Savannah, Ga, and St. Augustine, Florida ” ( Bailey 1851: 41). It thus seems reasonable to assume that the name ‘ Zygozeros [sic] ( Denticella ?) ’ mobilensis refers to the earlier Odontella mobilensis . The online catalogue refers to “ Zygoceros spp. Outside Mobile Bay, inside of Mobile Point, Alabama; 8 fathoms; J. W. Bailey Coll. 883”, which may be syntype material (http://www2.huh.harvard.edu/diatom/baileycat.htm).

Frustules in girdle view rectangular with narrow tubular elevations at apices and two long, hollow spines lying between. Apical axis 45–200μm, areolae 14–16 in 10 μm ( Hendey 1964, Hasle & Syvertsen 1996). Valve face lanceolate, sinuous, bordered by crenulated marginal ridge separating valve face from expanded mantle; mantle with produced apices ( Figs 1, 2, 6 ). Areolae loculate with internal foramina, on mantle and valve face in bi- and tri-seriate rows of fine pores between hyaline rows, interrupted by small spines, those on valve face in transapical rows bordering central annulus ( Figs 3–4 ). Annulus with hyaline margin, interior with numerous poroids surrounding hyaline circular areas ( Fig. 5 ). Rimoportulae 2, opening externally through long tubular spine, with hyaline surround ( Fig. 3 ), positioned diagonally and sub-marginally within valve face ( Figs 1, 2, 6 ).

Observations:— Lavigne et al. (2016) provide images of the living cell having ‘many, small discoid chloroplasts and a central nucleus’ ( Lavigne et al. 2016: figs 66–71). For further details see Ashworth et al. (2013: fig. 4a, d) and Lavigne et al. 2016: 318–320).

The description above is based on material from “Wunderluss” (locality unknown, ex Brigger colln, BM).

Figures

FIGURES 1–7. Trieres mobiliensis (J.W. Bailey)Ashworth & E.C. Theriot (“Wunderluss”, locality unknown ex Brigger colln, BM). Fig. 1. Valve tilted showing sinuous valve face bordered by crenulated marginal ridge extending between narrow elevation; annulus (sternum) indicated by arrows; scale bar = 38 μm. Fig. 2. Mantle view: deep mantle with produced apices, narrow outwardly directed elevations and two very long tubular spines (40–45μm) with forked apices, which are the openings from each rimoportula;; scale bar = 38 μm Fig. 3. Exterior, valve face with triseriate transapical rows of poroids, crenulated marginal ridge and opening of (fractured) spine; scale bar = 6 μm. Fig. 4. Flattened summit of elevation with ocellus on distal face; scale bar = 5 μm. Fig. 5. Annulus (sternum) with hyaline border, internal scattered poroids with circular hyaline areas; scale bar = 4.3 μm Fig 6. Flat exterior, narrow annulus (sternum) extending just beyond base of hollow spines (arrows); scale bar = 38 μm. Fig. 7. Reproduction of illustrations for “Zygoceros (Denticella?) mobiliensis