Diommatetras grossa Komura (2001: 77

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 : 30-32

publication ID

https://doi.org/ 10.11646/phytotaxa.382.1.1

DOI

https://doi.org/10.5281/zenodo.13724250

persistent identifier

https://treatment.plazi.org/id/12590703-F401-FF88-22DC-F929FB4A26FD

treatment provided by

Felipe

scientific name

Diommatetras grossa Komura (2001: 77
status

 

Diommatetras grossa Komura (2001: 77 , figs 55–75, text-fig. 3) ( Figs 105–110 View FIGURES 105–110 )

Type:— Japan: Miocene Morito Formation, “Km-5912…Calcareous nodules…collected from one of the serial rocky shoals submerged beneath the upper tidal level along the sand beach at Morito in the west side of the Miura Peninsula (Lat. 35° 16’ 06”N, Long. 139° 34’ 24”E, Text-fig.1)” ( Komura 2001: 70), “Km-5912 (4) = 14.8 X 129.1 (Fm39901) (holotype)” = Komura (2001: fig. 14).

Valves quadrate with two opposing poles narrower and longer than the other two, margins concave ( Fig. 105, 109 View FIGURES 105–110 ), length 39μm, breadth 36.5μm ( Komura 2001: 77, gives 25.5–33μm long, 21.5–31.5μm breadth). At narrower poles short elevation with ocellus at its summit extends outwards ( Fig. 105 View FIGURES 105–110 ). Valve centre oval, distinctly convex ( Figs 105, 106, 110 View FIGURES 105–110 ), the longer axis lying towards shorter apices.A series of radially aligned costae link valve centre to apices and a regular row of short costae link the narrow mantle to expanded hyaline valve margin ( Figs 105, 109 View FIGURES 105–110 ). Central area depressed covered externally with anastomosing costae forming irregular reticulate pattern, spines at junctions. Poroid areolae lie within anastomosing costae, the majority occluded by raised cribrum ( Fig. 107 View FIGURES 105–110 ), occasional specialised pore present ( Figs 107, 108 View FIGURES 105–110 , arrow). Areolae ca. 12 in 10μm. Rimoportulae 2, each positioned at base of longer axis of central area opening externally through long tubular spine ( Figs 105, 109 View FIGURES 105–110 ), internally through a slit between raised lips ( Fig. 108 View FIGURES 105–110 ).

Observations:— Diommatetras appears to be closely related to Amphipentas . For a more detailed account see Komura (2001: 77–80).

This description is based on specimens from Atlantic City well at 406 ft., New Jersey, USA.

Kingdom

Chromista

Phylum

Ochrophyta

Class

Bacillariophyceae

Order

Triceratiales

Family

Odontellaceae

Genus

Diommatetras

Loc

Diommatetras grossa Komura (2001: 77

Sims, Pat A., Williams, David M. & Ashworth, Matt 2018
2018
Loc

Diommatetras grossa

Komura, S. 2001: 77
2001
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