Pherecardites Horst 1912

Genus Pherecardites Horst, 1912

Pherecardites Horst, 1912: 33.

Branchamphinome Hartman, 1967: 42 n. syn.

TYPE SPECIES. — Pherecardites parva Horst, 1912, by monotypy.

GENDER. — Feminine, after the epithet originally proposed for the type species, parva; Brown (1954: 590) indicates parvus is a Latin masculine adjective, meaning little or small (parva feminine, parvum neuter (see below).

DIAGNOSIS. — Amphinominae with chaetiger 1 dorsally incomplete. Caruncle with a median ridge and separate, diverging lateral lobes. Branchiae from chaetiger 1. Neurochaetae spurred, with denticles along inner side.

REMARKS

Pherecardites Horst, 1912 was described without an illustration of the anterior end. Fauchald (1977) included Pherecardites Horst, 1912 in his key to all genera; however, Fauchald regarded the body shape of Branchamphinome as oval, whereas for Pherecardites it was assumed as rectangular. Nevertheless, Hartman (1967: 43) indicated the body shape of the type species, B. antarctica Hartman, 1967 changes during development: “Smaller individuals resemble the short Chloeia whereas longer ones are more like Eurythoe.” The latter has been regarded as having rectangular body.

Consequently, Pherecardites and Branchamphinome have the same body shape and types of chaetae. What about the caruncle? Horst (1912: 33) indicated “caruncle consisting of a median axis and some lateral lamellae, directed backwards.” And in describing the type species, P. parva, a few lines below, he wrote: “its caruncle extends over three segments and consists of a median axis and four lateral lobes, directed backwards.” Hartman (1967: 43) indicated, in the description of the type species, B. antarctica, “the caruncle is tripartite, consisting of a larger, longer median lobe with lateral branches, and a pair of shorter lateral lobes […]” These two descriptions indicate a very similar shape, and after the study of type specimens, the two genera are herein regarded as synonyms.

Pherecardites Horst, 1912 might be regarded as a name applied to fossils (ICZN 1999, Art. 20) and consequently, it could not “be used as the valid name of a taxon”. Further, as indicated in the example given for the same article, the genus-group name might be available if proposed “for genus-group of taxa of fossils […] and not merely to indicate fossil members of genera of extant animals”. Horst (1912) proposed Pherecardites, forming the name after Pherecardia Horst, 1886, but he was not referring to any fossil members of the same group. Consequently, it cannot be rejected as a valid name.

There are a few instances where a similarly ending genus-group name has been regarded as valid, such as Tringites Cabanis in Gundlach, 1856 (Aves, Scolopacidae), or Oceanites Keyserling & Blasius, 1840 (Aves, Hydrobatidae).On the other hand, Read & Fauchald (2022) explained the etymology as: “The name of the genus is formed by the postposition of the suffix of Greek origin - ites, used to form adjectives, especially those to identify groups as ‘those belonging to’, to the name of the genus Pherecardia Horst, 1886, and seems to be used to indicate the resemblance of the new genus Pherecardites with Pheracardia.” On the other hand, the suffix - ites is “to be treated as masculine unless its author, when establishing the name, stated that it had another gender or treated it as such by combining it with an adjective species-group name in another gender form” (ICZN 1999, Art. 30.1.4.4). As indicated above, because Horst used the feminine (parva) species-group name, the gender of the genus must be treated as feminine.

Hartman (1967) compared Branchamphinome with Benthoscolex Horst, 1912 because both have tripartite caruncle, and concluded they differ because the former has eyes, and branchiae from chaetiger 1, whereas the latter had no eyes, and branchiae from chaetiger 6. Kudenov (1993) modified the diagnosis but restricted the comparison to Benthoscolex. After Horst (1912) the presence of spurred neurochaetae with denticles along the inner side in Pherecardites resembles Hermodice, although some other genera also have this type of neurochaetae such as Benthoscolex, Linopherus de Quatrefages, 1866, Paramphinome Sars in Sars, 1872 and Pareurythoe Gustafson, 1930. Horst likely restricted the comparison to Hermodice and Pherecardia because they also have complex caruncle, as opposed to those present in the other genera. Benthoscolex, however, has a caruncle with three longitudinal lobes directed posteriorly, but they rise from the same point, not from a single median ridge, as is the case in Pherecardites.

As currently redefined, Pherecardites Horst, 1912 includes Branchamphinome Hartman, 1967. Consequently, the species described in the latter genus must be newly combined such that Pherecardites includes P. antarctica (Hartman, 1967) n. comb., P. islandica (Detinova, 1968) n. comb., P. kohtsukai (Jimi in Jimi et al. 2021) n. comb., P. parva Horst, 1912, P. quinquemaculata Augener, 1927, and P. tropicalis (Barroso, Ranauro & Kudenov, 2017) n. comb.

(modified after Jimi et al. 2021)

1. Prostomium with eyes, sometimes coalescent; first branchiae with 3 or more filaments............................ 2

— Prostomium with indistinct eyes; body pale; first branchiae with 1-2 filaments............................................................................................................................................................. P. parva Horst, 1912, Indonesia

2(1). Median segments branchiae with 15-20 filaments; body colorless................................................................................................. P. antarctica (Hartman, 1967) n. comb. (redescr. Kudenov 1993: 95), Antarctic Seas

— Median segments branchiae with 4-12 filaments; body variable............................................................... 3

3(2). Body pale; eyes nearly coalescent, forming an 8-shaped spot............................................................................. P. islandica (Detinova, 1968) n. comb. (recorded as B. antarctica by Amoureux 1982: 34), NE Atlantic

— Body with dorsal pigmentation; eyes separate, not coalescent................................................................... 4

4(3). Median branchiae with 4-8 filaments....................................................................................................... 5

— Median segments with about 12 filaments; dorsal pigmentation includes 5 spots, three dorsal and two interramal.............................................................................. P. quinquemaculata Augener, 1927, New Zealand

5(4). Venter of first four chaetigers broadly pigmented, following segments pale................................................................................................................................. P. kohtsukai (Jimi in Jimi et al., 2021) n. comb., Japan

— Venter with similar pigmentation along body................................................................................................................................................. P. tropicalis (Barroso, Ranauro & Kudenov, 2017) n. comb., SW Atlantic