Amphipentas juncta (A. Schmidt) De Toni (1894: 912)

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 : 27

Amphipentas juncta (A. Schmidt) De Toni (1894: 912) ( Figs 91–94 )

Basionym: Triceratium junctum A. Schmidt (1886 : pl.98, figs 1–2)

Synonym: Biddulphia juncta (Schmidt) Mann (1925: 42)

Type:— “[Figs] 1, 3. Ngucy, Ostküste v. Madagascar, 2 Seychelles I (Weissfl)” ( Schmidt 1886: pl. 98, figure legend)

Observations:— A quadrangular form that differs from A. pentacrinus and A. boryana in having short, stout costae linking the base of the squat elevations to the valve centre ( Fig. 91 ) and in having areolae with external primary and secondary anastomosing costae forming an irregular pattern ( Fig. 92 ) within which one specialized pore mostly lies ( Fig. 93 , arrow).

The notes above are based on material from Port Shepstone, Natal, South Africa.

Figures

FIGURES 91–94. Amphipentas juncta (A. Schmidt) De Toni (Port Shepstone, Natal, South Africa). Fig. 91. Valve exterior tilted with four slightly raised triangular elevations separated from valve face by short costae; valve covered in anastomosing costae, a row of costae linking valve mantle to expanded valve margin; scale bar = 60 μm. Fig. 92. Ocellus with hyaline rim, anastomosing costae enclosing groups of poroid areolae; scale bar = 15 μm. Fig. 93. Anastomosing costae enclosing poroid areolae occluded by cribra and occasional specialised pore (arrow), note openings from three rimoportulae; scale bar = 10 μm. Fig. 94. Interior with openings from two rimoportulae; scale bar = 5 μm.