Laciniporus arabicus gen. et sp. nov. (Dinophyceae, Peridiniales), a new thecate, marine, sand‐dwelling dinoflagellate from the northern Indian Ocean (Arabian Sea)¹

Abstract

A new thecate, photosynthetic, sand-dwelling marine dinoflagellate, Laciniporus arabicus gen. et sp. nov., is described from the subtidal sediments of the Omani coast in the Arabian Sea, northern Indian Ocean, based on detailed morphological and molecular data. Cells of L. arabicus are small (16.2-30.1 μm long and 13.1-23.2 μm wide), dorsoventrally compressed, with a small apical flap-shaped projection pointing to the left. The thecal plate pattern is distinguished by minute first precingular plate and sulcus, which extends into the epitheca, with large anterior and right sulcal plates. The Kofoidian thecal tabulation is Po, X, 4', 2a, 7'', 6c, 6s, 5''', 2''''. Morphologically, the revealed plate pattern has an affinity to the Peridiniales, and LSU rDNA based phylogenetic analyses placed L. arabicus within the Thoracosphaeraceae, close to calcareous-cyst producing scrippsielloids, predatory pfiesteriaceans, and photosynthetic freshwater peridinioids Chimonodinium lomnickii and Apocalathium spp. However, the thecal plate arrangement of L. arabicus differs noticeably from any currently described dinoflagellates, and the species stands out from closely related taxa by extensive differences in physiology and ecology.

Morphology and Molecular Phylogeny of a New Marine, Sand‐dwelling Dinoflagellate Genus, Pachena (Dinophyceae), with Descriptions of Three New Species

“…In contrast, Pachena has a hook that points to the left dorsal (to lateral) side and is part of the fourth apical plate, similar to the hook in Aduncodinium (Kang et al. ), Laciniporus (Saburova and Chomérat ), and Herdmania (e.g., Reñé et al. ) that points to the left lateral side.…”

“…The apical pore complex of Aduncodinium and Laciniporus comprises a canal plate that is typical for peridinoid taxa (Kang et al. , Saburova and Chomérat ), a trait not detected for Pachena species. Aduncodinium further differs in having only two anterior intercalary plates and a relative symmetric tabulation (Kang et al.…”

“…). A complex sulcal list has been described as distinctive feature of Laciniporus (Saburova and Chomérat ). It is equivalent to these internal sulcal lists.…”

“…), Pellucidodinium (Onuma et al. ), Laciniporus (Saburova and Chomérat ), and Psammodinium (Reñé and Hoppenrath ).…”

“…, Reñé et al ); Apicoporus has finger‐like projections (Sparmann et al. ); Laciniporus has a small flap‐shaped projection (Saburova and Chomérat ); and Sinophysis has parallel upright projections (Hoppenrath 2000c, Chomérat ). Many thecate, benthic dinoflagellate taxa have unusual tabulation patterns that are difficult to relate to the known tabulations in planktonic taxa (Hoppenrath et al.…”