Title:Speciation and Infrageneric Classification in the Planktonic Dinoflagellate Tripos (Gonyaulacales, Dinophyceae)
Volume: 1
Issue: 3
Author(s): Fernando Gómez*
Affiliation:
- Carmen Campos Panisse 3, 11500 Puerto de Santa María,Spain
Keywords:
Ceratium, Dinoflagellata, Dinophyta, phytoplankton, plankton, systematics.
Abstract: Background: The genus Tripos, formerly known as marine species of Ceratium, is the
dinoflagellate with the greatest number of species and infraspecific taxa (~800) due to the high
morphological intraspecific variability of numerous species. In the past, the species of Tripos were
proposed into distinct genera.
Objective: To propose an infrageneric classification and to review the taxonomy and nomenclature
of each taxon in order to establish the correct species and synonymy.
Methods: Observations from the Mediterranean Sea, and Atlantic and Pacific Oceans, a review of
the original descriptions and further literature, and the available molecular data.
Results: A re-instatement of this generic split is not justified due to the difficulties to circumscribe
the basal subgenera Amphiceratium and Archaeceratium, and the polyphyletic character of Biceratium.
The subgenus Amphiceratium is dismembered after the classification of the sections Inflata
and partially Fusiformia into Archaeceratium. The subgenus Tripos (autonym) replaces other
names such as Tripoceratium or Orthoceratium. Based on the original descriptions, the records of
T. furca and T. lineatus correspond to T. eugrammus and T. furca, respectively, and T. macroceros
has been reported as T. contrarius. The names T. belone and T. carriensis have been misapplied for
T. pacificus and T. volans, respectively. Tripos arcuatus, T. gracilis, T. inclinatus, T. scapiformis
and T. subcontortus are revived to replace T. euarcuatus, T. declinatus, T. horridus, T. longirostrum
and T. contortus, respectively. The species T. ramakrishnae and T. fusus var. schuettii were
described from individuals infected by endoparasites. Tripos rotundatus comb. nov. is proposed for
C. digitatum var. rotundatum.
Conclusion: Tripos is restricted to 57 correct species, although the speciation and synonymy are
incomplete due to lack of studies in the life cycle and molecular data.
