Flabelliderma Hartman, 1969

Salazar-Vallejo, Sergio I., 2007, Revision of Flabelliderma Hartman, 1969 (Polychaeta: Flabelligeridae), Journal of Natural History 41 (33 - 36), pp. 2037-2061 : 2039-2041

Flabelliderma Hartman, 1969

Flabelliderma Hartman 1969, p 286 ; Fauchald 1977, p 116 –117; Light 1978, p 683 (partim).

Type species. Stylarioides papillosa Essenberg, 1922 , reinstated.

Diagnosis (emended)

Body papillae abundant, usually grouped forming dorsal and lateral tubercles, making elongate thick notopodial lobes, free from from the rest of the body. Cephalic hood reduced. Branchiae cirriform, sessile on a branchial plate, arranged in two lateral groups. Nephridial lobes placed medially on the branchial plate, separated from the branchiae. Parapodia lateral, homogeneous. Notopodial lobe thin or ovoid, often including globular or vesicular papillae. Neurohooks multiarticulated; handle articulated, crest entire. Free-living in rocky or mixed bottoms, rarely symbiotic with sponges.

Discussion

Hartman (1961, p 118) proposed Flabelligera essenbergae as a replacement name for Stylarioides papillosa Essenberg, 1922 ; in her catalogue, she had regarded this name as a secondary junior homonym of Siphonostomum papillosum Grube, 1840 , described from the Mediterranean Sea ( Hartman 1959, p 416). However, Siphonostoma papillosum was regarded, in turn, as a questionable synonym of Flabelligera affinis Sars, 1829 , or Pherusa monilifera delle Chiaje, 1831 ( Hartman 1959, p 420) which are very different genera. However, she had regarded Stylarioides papillosa (Grube) as a member of Flabelligera ( Hartman 1959, p 421) , but based on the study of type material, this conclusion is incorrect.

This confusion was due to the fact that Grube (1850, p 320) regarded his species as a junior synonym of Siphonostoma diplochaitus Otto 1821 , which belongs in Flabelligera . However, Grube himself later solved the problem by regarding his species as a junior synonym of Stylarioides monilifer , which was commented upon several times in his revision ( Grube 1877, p 60, 67, 71). Further, this synonymy was repeated by Fauvel (1927, p 118); unfortunately these synonymy statements were overlooked by Hartman. Therefore, Siphonostomum papillosum Grube , and Stylarioides papillosa Essenberg are not congeneric, and following Article 59.4 (International Commission on Zoological Nomenclature ( ICZN) 1999), this should be resolved. Thus, the solution should involve a new combination for the original name, instead of a replacement name, the original name should be used as the type species of the genus, and Flabelliderma essenbergae Hartman, 1961 , must be regarded as a junior objective synonym of Stylarioides papillosa Essenberg, 1922 (see below).

Flabelliderma contains only two species after Hartman’s key (1969, p 286): F. essenbergae and F. commensalis . She noticed the large notopodial development in what she regarded as the type species, although neuropodial alignment is very different as well. Later, Fauchald (1977, p 116–117) presented the genus as monotypic, with Flabelligera commensalis Moore, 1909 , as the type species, and added a diagnostic feature improving the original definition to: ‘‘body papillae with thick mucus and encrusted with debris’’. Light (1978, p 682–685) noticed these confusions, brought back F. commensalis to Flabelligera , and emended the generic definition stressing the long pedunculate and vesicular papillae, as well as the enlarged notopodial lobes. This definition is partially followed here, but F. commensalis does not fit in Flabelligera because its neuropodia are placed very close to the midventral line, and because of its symbiotic habit. This issue will be documented elsewhere.

Thus, in comparison with Flabelligera , the main diagnostic features for Flabelliderma are that individual papillae, or their groups, are easily seen because they make sediment-loaded tubercles, and by the large notopodial lobe development, often with large vesicular papillae. As currently redefined, the genus includes Flabelliderma papillosa ( Essenberg, 1922) n. comb., F. berkeleyorum n. sp., F. claparedei ( de Saint-Joseph, 1898) n. comb., F. gourdoni ( Gravier, 1906) n. comb., F. lighti n. sp., F. ockeri n. sp., and F. pruvoti ( Fauvel, 1930) n. comb. Three additional new species are described: F. berkeleyorum n. sp. collected while swimming in Friday Harbor, Washington, F. lighti collected in a shallow subtidal sponge in Guadalupe Island, and F. ockeri collected in dead giant kelp holdfasts, a species that has previously been identified as F. essenbergae (i.e. F. papillosa ).

Diagnostic features

On the basis of this redefinition, Flabelliderma is not monotypic and certainly it is far from being a well-known genus. Since there are species collected in tropical, temperate, or polar environments, many more species might remain undescribed. The following are the main diagnostic features for the species in the genus.

Body papillae. There are several differences in body papillae among different Flabelliderma species. Individual papillae are lageniform, often provided with long stems and sometimes carry a long mucro. Most species adhere sediment particles on each individual papillae; these particles are mostly fine, loosely adhered to the papillae but sometimes they form dehiscent clavate sediment tubercles, with abundant sediment ( Figures 1B, C , 2D , 3A, D , 5A, B ), or with little sediment ( Figure 4A–C ), or stiff rectangular tubercles, especially dorsally ( Figure 6A, B, D ). The only exception is F. pruvoti , because their papillae are spherical or with a tiny mucro, and are mostly sediment-free ( Figure 7A–C ). Dorsal papillae are often fused forming large sediment tubercles or masses and their relative number per transverse line, along a median segment, is given to clarify specific features.

Notopodial lobes. The notopodial papillae fuse to each other forming notopodial lobes, which often include globular or vesicular papillae. This term refers to their position, but it must be kept in mind that they are not body wall outgrowths from the notopodia; they are rather a complex construct of notopodial papillae. The notopodial lobes might be thin or ovoid ( Figures 2A, B, E , 3D , 4C , 5D , 7A–C ), or more or less funnel-shaped or distally expanded ( Figure 5D ). They may also differ in the relative amount of sediment adhered on individual papillae; thus, those having sediment restricted to their bases give a pilose or ‘‘hairy’’ appearance to the lobes ( Figures 4B, C , 5D ). However, if the papillae are spherical, with a long stem but without mucro, the sediment will be very sparse and the notopodial lobes will appear clean ( Figure 7C ).

Notochaetae. All notochaetae are covered by the notopodial lobes. There may be some variations in their number, in the type of articulation, or in the relative size of the articles along the chaetae. The number of notochaetae may be size-dependent and probably of limited usage. However, the pattern of articulation might be more specific, although some chaetae have articulations better defined or extended throughout its length. Thus, the articles can be short if they are wider than long, medium-sized if they are as long as wide, and long if they are longer than wide. Further, the articulation size varies among the chaetae and this feature is useful.

Neurohooks. Neurohooks can be divided in two parts. The exposed portion includes the distal piece, or crest, which is often thin and curved; in most species it is tapering and sharp, and rarely it can be medially expanded and blunt ( Figure 7D ). The handle is not exposed and it is multiarticulated; the articulations will be referred to as short, if they are wider than long, medium-sized if they are as long as wide, and long if they are longer than wide. The number of long articles in the median region, as well as their relative length, differs among species, and there is a tendency to become shorter and poorly-defined towards the crest. The relative size and degree of pigmentation of the crest varies along the body; anterior or posterior neurohooks are more delicate, and slightly less pigmented, than those present in median chaetigers.

Figures

Figure 1. Flabelliderma papillosa (Essenberg, 1922) n. comb. (A) Neotype (LACM-AHF 2187) in dorsal view; (B) neoparatype (LACM-AHF), anterior end in dorsal view; (C) another paraneotype, eversible anterior end in frontal view; branchiae and palps removed; (D) same, a complete median chaetiger in frontal view; (E) tip of neurohook from a median chaetiger. Scale bars: 1.5 mm (A); 1.0 mm (B); 0.5 mm (C, D); 90 Mm (E).

Figure 2. Flabelliderma berkeleyorum n. sp. (A) Holotype (USNM-40475) in dorsal view; (B) same, anterior end in dorsal view; (C) paratype, eversible anterior end in frontal view (palps and branchiae lost); (D) holotype, close-up of some median chaetigers, in dorsal view, showing the dorsal tubercles and notopodial lobes; (E) paratype, median parapodia showing the regularly constricted notopodial lobes; (F) paratype, tip of neurohook from a median parapodia. Scale bars: 1 mm (A); 0.4 mm (B); 0.25 mm (C, E); 0.33 mm (D); 40 Mm (F).

Figure 3. Flabelliderma claparedei (de Saint-Joseph, 1898) n. comb. (A) Non-type specimen (MNHN-449) in dorsal view; (B) holotype (MNHN-447), anterior end in dorsal view; (C) eversible anterior end (MNHN-448) in frontal view, distorted by compression; branchiae and palps removed; (D) close-up of the median region, in ventral view, showing the sediment tubercles (MNHN-449); (E) same, tip of neurohook from a median parapodium, surrounding cuticle and papillae removed. Scale bars: 2 mm (A, B); 1.25 mm (C); 1.00 mm (D); 40 Mm (E).

Figure 4. Flabelliderma gourdoni (Gravier, 1906) n. comb. (A) Holotype (MNHN-446) in lateral view; (B) same, close-up of the anterior end in lateral view; (C) same, posterior end in lateral view; (D) same, close-up of papillae of the neuropodial lobe; (E) same, tip of neurohook from a median parapodium with surrounding cuticle and a papilla tip; (F) non-type specimen (MNHN-A184), anterior end in ventral view with two copepod egg-masses indicated by arrows; both removed, slightly enlarged as inserts above it. Scale bars: 3.8 mm (A); 0.8 mm (B); 1.0 mm (C); 110 Mm (D, E); 50 Mm (F).

Figure 5. Flabelliderma lighti n. sp., holotype (CAS-168303). (A) Dorsal view; (B) anterior end in dorsal view; (C) eversible anterior end in frontal view; branchiae and palps removed; (D) median body chaetigers, seen from below, showing a large globular papilla; (E) tip of a neurohook from a median parapodium, broken, with some papillae. Scale bars: 1.5 mm (A, B); 0.9 mm (C); 0.3 mm (D); 45 Mm (E).

Figure 6. Flabelliderma ockeri n. sp. (A) Holotype (LACM-AHF-536), dorsal view; (B) same, close-up of the anterior end, dorsal view; (C) non-type specimen (ECOSUR), eversible anterior end in frontal view, branchiae and palps removed; (D) median chaetiger from paratype (LACM-AHF-537), showing globular papillae in the notopodial lobe; (E) tip of a neurohook from a median parapodium, without cuticle or papillae. Scale bars: 2 mm (A); 1 mm (B); 0.4 mm (C); 0.8 mm (D); 60 Mm (E).

Figure 7. Flabelliderma pruvoti (Fauvel, 1930) n. comb. (A) Holotype (MNHN-194), oblique lateral view; (B) same, close-up, lateral view of the anterior end; (C) same, ventral view of the lateral part of the body; (D) paratype (MNHN-195), tip of a neurohook from a median parapodium, without cuticle or papillae. Scale bars: 2 mm (A); 1.5 mm (B); 0.5 mm (C); 90 Mm (D).