taxonID	type	description	language	source
547B87D09B5CC94CFEACB11FFCAE0EC3.taxon	description	(Figures 1 – 4, 5 B, 7 A, 8)	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5CC94CFEACB11FFCAE0EC3.taxon	materials_examined	Material examined Five incomplete specimens were collected in three BIOICE samples (Table 1). BIOICE sample 2414 (1 spec. in SEM stub, IINH 27830); BIOICE sample 2474 (1 spec. in SEM stub, IINH 27830); BIOICE sample 3500 (3 spec., IINH 27831).	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5CC94CFEACB11FFCAE0EC3.taxon	description	Description Most complete specimen 9 mm long, 0.4 mm wide, with 14 chaetigers. Prostomium conical, anteriorly rounded, slightly flattened dorsoventrally (Figure 2 A, B). Eyes absent. Nuchal organs as deep grooves posterolateral to prostomium. Peristomial palps and palp scars not observed. Pharynx sac-like, eversible and unarmed. Anterior body region slightly flattened dorsoventrally, with eight short chaetigers (CH) (Figures 2 A, B, 5 B). CH 1 – 8 short, somewhat more than twice as wide as long. Chaetigers progressively longer from CH 9 onwards. CH 9 first elongated segment, longer than wide; length (as distance from chaetal bundle to chaetal cincture of CH 10) about three times longer than CH 8. Branchiae lacking in all specimens but eight pairs of branchial scars present from CH 2 to CH 9 (Figures 2 A, B, 5 B). CH 1 abranchiate (no scars). The remaining chaetigers strongly elongated and cylindrical in cross-section; length increasing backwards; CH 10 about four times longer than CH 9, CH 11 about 2.5 times longer than CH 10. CH 1 – 9 with biramous parapodia; with notopodial and neuropodial chaetal fascicles well separated. From CH 10 onwards parapodia as elongated ridges forming a nearly closed flange-like cincture near anterior margin of segment (Figures 2 A, B, 3, 5 B). Chaetae of CH 1 – 9 simple capillaries, in fan-shaped fascicles (Figure 2 C). No neuropodial hooks in any anterior chaetiger. From CH 10 onwards chaetae arranged in two rows (Figures 2 D, 4 A, B): anterior row of thick subuluncini (Figure 4 D – H) and posterior row of simple fine capillaries (Figure 4 C). Aristate or acicular spines not observed. Occurrence In Iceland H. longissima sensu Hartman (1965) is restricted to the slope bottoms of the southwestern coast, south Reykjanes Peninsula (Figure 7 A). Depth range: 784 – 834 m; temperature range: 5.36 – 5.82 ° C (Table 1).	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5CC94CFEACB11FFCAE0EC3.taxon	distribution	Distribution Heterospio longissima was described by Ehlers (1874) based on an incomplete specimen from the northeast Atlantic. Hartman (1965) reported the species from the western Atlantic. However, Laubier et al. (1972 – 73) pointed out that Hartman’ s material was different from that of Ehlers, but further comparisons to test whether the latter corresponded to a different species were not possible because the holotype was apparently missing (Borowski 1994, p. 130). Therefore, Laubier et al. (1972 – 73) cautiously considered the existence of two forms of this species: the nominal species and H. longissima sensu Hartman (1965). Since then, most subsequent reports of longosomatids were assigned to either form of H. longissima (e. g. Imajima 1974; Intès and Le Loeuff 1977; Kirkegaard 1980; Amoureux 1982; Rosenfeldt 1989; see Figure 8), but the character combinations of these specimens did not always match those of the two forms (cf. Hartman 1974; Uebelacker 1984). In view of the aforementioned worldwide reports attributed to the species, it is likely that several different species are still waiting to be described, particularly all those reported outside the North Atlantic Ocean (e. g., Hartman 1974; Imajima 1974; Intes and Le Loeuff 1977; Rosenfeldt 1989).	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5CC94CFEACB11FFCAE0EC3.taxon	discussion	Remarks Both Heterospio longissima sensu Hartman (1965) and the nominal species have in common that the first elongated segment is CH 9, but the degree of elongation is different. In H. longissima sensu Hartman CH 9 is about three times longer than previous chaetigers, whereas in H. longissima sensu Ehlers CH 9 is about as long as all the anterior segments together (see Laubier et al. 1972 – 73, fig. 3; Borowski 1994, notes 2 and 3 in table 2 on pp. 140 – 143; Bochert and Zettler 2009, key on p. 737). Additionally, H. longissima sensu Hartman has chaetae forming cinctures from CH 10 onwards provided with thick subuluncini and fine capillaries, whereas in H. longissima sensu Ehlers all body chaetigers are provided with biramous parapodia with only simple capillaries (see Laubier et al. 1972 – 73, p. 250) (Figure 5 A – B). Heterospio longissima sensu Hartman most closely resembles Heterospio sinica Wu and Chen, 1966 from the China Sea, Heterospio catalinensis (Hartman, 1944) from off California and Heterospio peruana Borowski, 1994 from off Peru, because all share having CH 9 as the first elongated chaetiger, although clearly shorter than all previous segments as a whole (Figures 5 B – D, 6 C). Heterospio catalinensis differs from the others by having acicular chaetae in the neuropodium of CH 1. Heterospio sinica and H. peruana are clearly distinguishable from Hartman’ s form of H. longissima by the presence of aristate chaetae on elongate segments. Moreover, while H. sinica also has eight pairs of branchiae in the thorax (Figure 5 D), H. peruana has only four pairs (Figure 6 C). Although aristate chaetae as illustrated by Bochert and Zettler (2009) were not observed, the shaft of the subuluncini seems to be articulated with the blade (Figure 4 C – H) in a similar manner to that illustrated by Wu and Chen (1966); Borowski (1994) and Wilson (2000 a) (see Discussion).	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5AC947FEABB3E3FD710B64.taxon	description	(Figures 6 B, 7 B, 9, 10)	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5AC947FEABB3E3FD710B64.taxon	materials_examined	Material examined Thirty-one specimens were collected in 10 BIOICE samples (Table 1). BIOICE sample 2392 (5 spec., IINH 27832 and 2 spec. in SEM stub IINH 27833); BIOICE sample 2407 (1 spec., IINH 27834); BIOICE sample 2414 (3 spec., MNCN 16.01 / 15211); BIOICE sample 2474 (7 spec., IINH 27835); BIOICE sample 2719 (1 spec., IINH 27836); BIOICE sample 2886 (1 spec., IINH 27837); BIOICE sample 2893 (1 spec., IINH 27838); BIOICE sample 3500 (5 spec., IINH 27839); BIOICE sample 3613 (4 spec., IINH 27840); BIOICE sample 3617 (1 spec., MNCN 16.01 / 15212).	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5AC947FEABB3E3FD710B64.taxon	description	Description Most complete specimen 16 mm long, 0.3 mm wide, with 11 chaetigers. Prostomium conical, anteriorly rounded (Figure 9 A – C); slightly flattened dorsoventrally. Eyes absent. Nuchal organs as deep grooves posterolateral to prostomium. Peristomial palps and palp scars not observed. Pharynx sac-like, eversible and unarmed (Figure 9 C). Anterior body region slightly flattened dorsoventrally (Figure 9 A). CH 1 – 6 short, somewhat more than twice as wide as long. CH 7 about 1.5 times longer than CH 6 (Figure 6 B). CH 8 much longer than wide, about four times longer than CH 7 (Figures 6 B, 9 A). Branchiae lacking in all specimens but three pairs of branchial scars present from CH 2 to CH 4 (Figures 6 B, 9 A – C). From CH 9 chaetigers strongly elongated and cylindrical in cross-section, length increasing backwards. CH 9 about three times longer than CH 8. CH 1 – CH 8 with biramous parapodia; notopodial and neuropodial chaetal fascicles well separated in all chaetigers. Chaetal cinctures near anterior margin of elongated segments not observed. Notochaetal fascicle of CH 7 and particularly CH 8 provided with longer chaetae and more dorsally located (Figures 6 B, 9 A, 10 A). All chaetae fine simple capillaries. No neuropodial hooks in anterior chaetigers. Modified chaetae (subuluncini, aristate or acicular spines) not observed. Occurrence Heterospio reducta was found at slope bottoms of the west (Snaefellsnes Peninsula and western Fjords) and southwestern (south Reykjanes Peninsula) coast (Figure 7 B). Depth range: 270 – 922 m; temperature range: 4.57 – 6.99 ° C (Table 1).	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5AC947FEABB3E3FD710B64.taxon	distribution	Distribution Originally described from off Algiers by Laubier et al. (1972 – 73), the species was later reported by Amoureux (1982) from the continental slope (500 – 1400 m) off west Ireland.	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
547B87D09B5AC947FEABB3E3FD710B64.taxon	discussion	Remarks Heterospio reducta is distinguished from most longosomatids by the smaller number of short anterior chaetigers (CH 1 – CH 6), with CH 7 being the first elongated chaetiger, while in other species the latter is either CH 8, CH 9 or CH 10. Laubier et al. (1972 – 73), while describing and illustrating CH 7 slightly longer than CH 6, consider CH 8 as the first posterior chaetiger; this is followed by Bochert and Zettler (2009) in their key of worldwide species of Heterospio. As no chaetal cinctures are present in this species, Laubier et al. (1972 – 73) used the segment size as evidence of the beginning of the mid-body region, instead of the shape of the chaetal bundles. Hence, in H. reducta the first mid-body chaetiger would actually be CH 7 rather than CH 8 (see above description and Figure 6 B). The only substantial difference between Icelandic specimens of H. reducta and those from the type locality is the presence of very long chaetae in the notopodia of CH 8, which are located more dorsally (Figures 9 A, 10 A). Heterospio reducta differs from specimens of H. longissima sensu Hartman, 1965 also found in Icelandic waters in the number of short anterior chaetigers (six in H. reducta and eight in H. longissima sensu Hartman) and by having only one type of chaeta; furthermore, in the latter species the chaetae form almost complete circles on elongated chaetigers, which are not observed in H. reducta. Heterospio reducta differs from H. mediterranea from the Mediterranean Sea and Heterospio sp. A as described by Uebelacker (1984) from the Gulf of Mexico in the number of short anterior chaetigers (seven in these species and six in H. reducta) and in the number of branchiae and chaetal composition, respectively. Hence, H. mediterranea has seven pairs of branchiae while H. reducta has only three; Heterospio sp. A has acicular hooks in the neuropodia of CH 1, whereas in H. reducta there are simple capillaries in both the notopodia and neuropodia. The species most similar to H. reducta is Heterospio angolana Bochert and Zettler, 2009 from the southeast Atlantic Ocean (Angola). This species has the same number of pairs of branchiae (three) and short anterior chaetigers (six) – although Bochert and Zettler (2009) consider CH 9 as first elongated chaetiger – but they differ in length of CH 8, being more elongated in H. reducta than in H. angolana (Figure 6 B, D) and in the very long chaetae of H. reducta on CH 8.	en	Parapar, Julio, Aguirrezabalaga, Florencio, Moreira, Juan (2014): First record of Longosomatidae (Annelida: Polychaeta) from Iceland with a worldwide review of diagnostic characters of the family. Journal of Natural History 48 (17): 983-998, DOI: 10.1080/00222933.2013.859316
