Phyllodoce Savigny

Salazar-Vallejo, Sergio I., 2022, New species of hesionid and phyllodocid polychaetes (Annelida, Errantia) from Clipperton Island, Zoosystema 44 (1), pp. 1-26 : 4-6

Genus Phyllodoce Savigny in Lamarck, 1818 sensu lato

Phyllodoce Lamarck, 1818: 316 . — Savigny 1822: 13, 42. — Pleijel 1991: 238; 1993b: 298. — de Oliveira et al. 2021: 5.

TYPE SPECIES. — Phyllodoce laminosa Savigny in Lamarck, 1818, by monotypy.

REMARKS

Phyllodoce Savigny in Lamarck, 1818 is the largest genus in the family because it includes over 100 valid species ( Pleijel 1991, 1993a, b). The authorship for the genus, as for most marine annelid taxa included by Lamarck (1818), must be attributed to Savigny, because Lamarck indicated he was making an abridged version of the large document Savigny had shared in the Royal Academy of Sciences, of the French Institute ( ICZN 1999, Art. 50.1.1), and available from 1809, although the publication date was fixed as 1822 ( Sherborn 1897), apparently based upon the second edition. Lamarck (1818: 279) indicated: “Néanmoins, la nature de notre ouvrage ne nous permet d’en donner qu’un extrait très-resserré” (Nevertheless, the nature of our work allows us to give just a very concentrated excerpt [free translation]).

Bergström (1914: 55-56) used and standardized 14 characters for revising the delineation and diagnosis for the phyllodocids. He proposed three new families, and among phyllodocids he proposed nine genera, six of which were regarded as valid by Fauchald (1977). Bergström (1914: 118) keyed out Anaitides Czerniavsky, 1882 , Phyllodoce and Sphaerodoce Bergström, 1914 by using the shape and length of the tentacular cirri (oblong or tapered, long in the former two, against globular, short in the latter), and the arrangement of pharynx papillae on the basal region (forming rows in Anaitides , versus diffuse in the two others). Bergström (1914) also indicated he was partially following the Phyllodoce species groups proposed by Augener (1913b: 213-215), based on pharynx papillae pattern and dorsal cirri shape. To these features, Bergström added the shape of the ventral cirri for his key to Anaitides species ( Bergström 1914: 139-140). Chamberlin (1919), and later Hartman followed Bergström and regarded Anaitides and Phyllodoce as separate genera throughout their publications; Fauchald (1977) included them as independent genera. Hartmann-Schröder initially regarded Anaitides and Phyllodoce as distinct genera, and later changed her mind and used subgenera in Phyllodoce .

Most authors, however, have preferred to regard them as subgenera. The first to provide explanations for this was Fauvel (1919: 357-359). Because of the problems with following Bergström formula for indicating the appendages of the first segments, especially for detecting the presence of chaetae, Fauvel rejected its use, although he emphasized ( Fauvel 1919: 357) Bergström “gave a correct importance to pharynx features”. Fauvel also indicated that “a more serious inconvenience of his classification was the multiplication of genera in a certainly abusive way” ( Fauvel 1919: 358). He also added that “after more than 20 years, I reject this atomization of genera, completely useless in polychaetes where species are relatively few in each family” ( Fauvel 1919: 359), and concluded: “However, in a genus including hundreds of species, the fractioning is more justified than in a genus having a small number of species, as is generally the case in polychaetes.” This was Fauvel, and he was both very productive and very influential on other colleagues working on polychaetes. Regretfully, the morphological features of the anterior end and pharynx papillation patterns were not evaluated, despite the fact that in several other errant families, these attributes are useful for separating similar genera.

Pleijel (1991) made the first phylogenetic analysis of the Phyllodocidae . He studied 21 taxa and assessed 26 characters, but the shape of antennae and tentacular cirri was not included, and his character 9 combined basal and distal regions of the pharynx, but the basal region was not clarified regarding papillae patterns, as opposed to the distal region. Among his conclusions, Pleijel (1991: 238) listed seven genera or subgenera as junior synonyms of Phyllodoce : Anaitides ; Aponaitides McCammon & Montagne, 1979; Paracarobia Czerniavsky, 1882, Protocarobia Czerniavsky, 1882, Phyllouschakovius Blake, 1988 , Sphaerodoce , and Zverlinum Averincev, 1972. This synonymy reflects that some diagnostic features were disregarded, such that these taxa were regarded as similar under that perspective.

Pleijel (1991, 1993a, b) hesitated about including Prophyllodoce Hartman, 1966 because he could not study the type material. This latter genus resembled Phyllodoce especially regarding the papillae pattern on the basal pharynx area, but the presence of two small dorsal tubercles on segment 1 was regarded as an additional pair of tentacular cirri, and used to separate it from Phyllodoce , as indicated in the original proposal ( Hartman 1966: 182, key, 187, diagnosis). Pleijel (1991, 1993b) was correct. In a newly described species of Anaitides (see below), there are two dorsal tubercles on segment 1, but it matches the generic delineation for Anaitides . These so-called tubercles, or additional tentacular cirri, were regarded as nuchal organs ( Gravier 1896: 341; Uschakov 1972: 123), and they are present in some species such as Phyllodoce laminosa ( Pleijel 1991: 239, fig. 1 A, B), the type species of Phyllodoce . Consequently, the presence of nuchal organs cannot be enough to separate Prophyllodoce from Phyllodoce .

The other genera are very homogeneous regarding the development of prostomial appendages and tentacular cirri, but they were originally proposed as different genera by using differences in the tentacular cirri pattern, and pharyngeal features, especially the spatial arrangement of papillae, and sometimes additional parapodial characters. For example, Chamberlin (1919: 100) keyed out Anaitides , Phyllodoce and Sphaerodoce by using the type of tentacular cirri, and for the two former ones, the arrangement of pharynx papillae.

Pleijel (1991: 238) also indicated that “splitting this large genus is desirable but should be based on defining properties for all subgroups and will have to await further studies”. Pleijel (1993b: 296, 298-299) returned to the problem and proposed recognizing three subgenera: Anaitides (incl. Aponaitides) with about 19 species, Phyllodoce (incl. Paracarobia and Sphaerodoce , perhaps Prophyllodoce ) with about 21 species, and Zverlinum (incl. Phyllouschakovius ) with three species. Most species could not be included in the above genera because “available specimens of many species are few and in poor condition” ( Pleijel 1993b: 297).

The standardized diagnoses for these subgenera are modified from Pleijel (1993b: 296, 298-299). They are herein regarded as distinct genera because they present a unique combination of morphological features, which was confirmed in the later phylogeny ( Pleijel 1993b). Diagnoses and incorporation of their type species ( ICZN 1999, Art. 13.2.3) are as specified below. These taxa can be separated with the key given below.