Until 1965, the Phylum was subdivided only in
genera. In that year, Tokioka ( 1965a,b) proposed
a new and revolutionary classification based on
morphological and phylogenetical (presently
under discussion) characters. The phylum was
divided into two classes: Archisagittoidea, which
includes the presumed fossil chaetognath
Amiskwia sagittiformis, and Sagittoidea which
includes all the present -day chaetognaths. The
latter class was in turn subdivided into two orders: Phragmophora which have transversal
musculature (phragma) in the trunk, musculature which is absent in the Aphragmophora
which have only primary and secondary muscle
bands in the trunk and tail. The orders were subdivided in families and the hypertrophic genus
Sagitta was subdivided into 11 genera. The old
name Sagitta remains for a few species. All new
taxa have new names. Since then, this classification has been further revised Salvini-Plaven
(1986) and Bieri (1991a,b). At present, the number of described species of chaetognaths is almost 200, but many of these will probably pass
into synonymy with others in the fu ture.
Whereas Bieri (1991a,b) and many other specialists concord with the new classification, other authors such as Alvarifio (1969), Pierrot-Bults
(1974, 1976, 1979), Kapp (1980), Boltovskoy
(1981), Furnestin and Ducret (1982) and Hagen
(1985) use the traditional nomenclature. Kapp
(1993) maintains that at present there is no valid
phylogenetic hasis to erect a new classification,
and that the new method contradicts the rules of
the International Cade of Zoologica! Nomenclature. Authors such as Dinofrio (1973) follow the
traditional nomenclature, but also report the
new names proposed by Tokioka. This is also the
criterion we have adopted in the present text.
Old Classification
Phylum CHAETOGNATHA Leuckart, 1854
Genus SAGITTA Quoy & Gaimard, 1827
7.1 Sagitta decipiens Fowler, 1905
7.2 Sagitta gazellae von Ritter-Zahony, 1909
7.3 Sagitta maxima Conant, 1896
7.4 Sagitta tasmanica (Thomson, 1947)
Genus EUKROHNIA von Ritter-Zahoney, 1909
7.5 Eukrohnia hamata Mobius, 1875
New classification
Phylum CHAETOGNATHA Leuckart, 1854
Class SAGITTOIDEA Claus & Grobben, 1905
Order APHRAGMOPHORA Tokioka, 1965
Family SAGITTIDAE Claus & Grobben, 1905
Genus Mesosagitta Tokioka, 1965
7.1 Mesosagitta decipiens Fowler, 1905
7.1 Decipisagitta decipiens Bieri, 1991
7.3 Mesosagitta maxima Conant, 1896
Genus Flaccisagitta_ Tokioka 1965
7.2 Pseudosagitta gazellae Bieri, 1991
Genus Serratosagitta Tokioka & Pathansali, 1963
7.4 Serratosagitta tasmanica (Thomson, 1947)
Family Eukrohniidae
Genus Eukrohnia von Ritter-Zahony, 1909
7.5 Eukrohnia hamata Mobius, 1875
genera. In that year, Tokioka ( 1965a,b) proposed
a new and revolutionary classification based on
morphological and phylogenetical (presently
under discussion) characters. The phylum was
divided into two classes: Archisagittoidea, which
includes the presumed fossil chaetognath
Amiskwia sagittiformis, and Sagittoidea which
includes all the present -day chaetognaths. The
latter class was in turn subdivided into two orders: Phragmophora which have transversal
musculature (phragma) in the trunk, musculature which is absent in the Aphragmophora
which have only primary and secondary muscle
bands in the trunk and tail. The orders were subdivided in families and the hypertrophic genus
Sagitta was subdivided into 11 genera. The old
name Sagitta remains for a few species. All new
taxa have new names. Since then, this classification has been further revised Salvini-Plaven
(1986) and Bieri (1991a,b). At present, the number of described species of chaetognaths is almost 200, but many of these will probably pass
into synonymy with others in the fu ture.
Whereas Bieri (1991a,b) and many other specialists concord with the new classification, other authors such as Alvarifio (1969), Pierrot-Bults
(1974, 1976, 1979), Kapp (1980), Boltovskoy
(1981), Furnestin and Ducret (1982) and Hagen
(1985) use the traditional nomenclature. Kapp
(1993) maintains that at present there is no valid
phylogenetic hasis to erect a new classification,
and that the new method contradicts the rules of
the International Cade of Zoologica! Nomenclature. Authors such as Dinofrio (1973) follow the
traditional nomenclature, but also report the
new names proposed by Tokioka. This is also the
criterion we have adopted in the present text.
Old Classification
Phylum CHAETOGNATHA Leuckart, 1854
Genus SAGITTA Quoy & Gaimard, 1827
7.1 Sagitta decipiens Fowler, 1905
7.2 Sagitta gazellae von Ritter-Zahony, 1909
7.3 Sagitta maxima Conant, 1896
7.4 Sagitta tasmanica (Thomson, 1947)
Genus EUKROHNIA von Ritter-Zahoney, 1909
7.5 Eukrohnia hamata Mobius, 1875
New classification
Phylum CHAETOGNATHA Leuckart, 1854
Class SAGITTOIDEA Claus & Grobben, 1905
Order APHRAGMOPHORA Tokioka, 1965
Family SAGITTIDAE Claus & Grobben, 1905
Genus Mesosagitta Tokioka, 1965
7.1 Mesosagitta decipiens Fowler, 1905
7.1 Decipisagitta decipiens Bieri, 1991
7.3 Mesosagitta maxima Conant, 1896
Genus Flaccisagitta_ Tokioka 1965
7.2 Pseudosagitta gazellae Bieri, 1991
Genus Serratosagitta Tokioka & Pathansali, 1963
7.4 Serratosagitta tasmanica (Thomson, 1947)
Family Eukrohniidae
Genus Eukrohnia von Ritter-Zahony, 1909
7.5 Eukrohnia hamata Mobius, 1875