Laubieriopsis cabiochi (Amoureux, 1982)

Zamora, José Luis, Parapar, Julio, Helgason, Gudmundur V. & Moreira, Juan, 2020, Taxonomy and distribution of Icelandic Fauveliopsidae (Annelida) collected during the BIOICE project, Journal of Natural History 53 (47 - 48), pp. 2951-2974 : 2967-2970

Laubieriopsis cabiochi (Amoureux, 1982)

( Figures 1 (d), 2(c), 3(g,h), 8 and 9; Table 1)

Material examined

4,400 specimens (50.11% of the total) collected in 97 samples ( Figure 1 (d); Table 1).

Description of BIOICE specimens

Body 2.0–10.0 mm long, 0.2–0.5 mm wide, 21 chaetigers ( Figure 8 (a)); prostomium and peristomium usually retracted within CH 1–4 ( Figure 8 (a–d)), partially everted in some specimens ( Figure 8 (f)). Cuticle with micropapillae only visible under SEM ( Figure 8 (e)). Three body regions: 1) anterior comprising prostomium, peristomium and CH 1–4, segments short with intersegmental grooves well delimited; one acicular per parapodial rami in CH 1–2 ( Figure 9 (a)), bidentate ( Figure 9 (b)) but unidentate in specimens <4 mm long; up to four unidentate aciculars per rami in CH 3–4 ( Figure 8 (d,e)); 2) median: CH 5–20, segments longer, lacking defined intersegmental grooves; each parapodial ramus provided with one thick acicular not protruding from parapodial wall and one capillary ( Figure 9 (c,d)), both types with scale cover ( Figure 9 (d)); 3) posterior region comprising only CH 21 and pygidium; CH 21 bearing elongated falcate aciculars ( Figure 9 (e)); pygidium uni- or bilobed, provided with three conspicuous papillae accompanied by a number of micropapillae ( Figure 9 (f,g)) . One interramal papilla, spherical, hardly visible under stereomicroscope; more developed in anterior segments and displaced towards notopodium ( Figures 8 (g) and 9(a,c)). One genital papilla located on posterior right side of CH 8 close to limit with CH 9 ( Figure 9 (c)).

Habitat and distribution

BIOICE specimens show a range of geographic distribution in Iceland similar to that of the two aforementioned species but within a narrower range of depth and temperature values (171–196 m; 5.18–7.61ºC; Figure 2 (c)). Samples are mostly distributed across western Iceland, from Vestman and Surtsey islands to Snaefelnes Peninsula south of Esternfjords ( Figure 1 (d)).

This species was previously reported in the Atlantic Ocean by Petersen (2000) from North Iceland to the Faroe Islands, at depths of between 265 and 1,157 m and mud volcanoes in the Gulf of Cádiz (southern Iberian Peninsula; Cunha et al. 2013).

Remarks

BIOICE specimens mostly agreed with descriptions provided by Petersen (2000) and Salazar-Vallejo et al. (2019), but some showed some variability in relevant taxonomic characters, such as the total number of chaetigers, number of chaetae per parapodium and number and location of genital papillae. For instance, seven specimens of 7–8 mm in length and 21 chaetigers showed two genital papillae (samples 2237, 2273, 2867, 3565, 3617 – 1 spec. each-, 2308 – 2 spec. -), while two 6-mm long specimens had 22 chaetigers (sample 2392), and one 8-mm long specimen had 20 chaetigers (sample 2398), all three with only one papilla.

On the other hand, one specimen (7-mm long, sample 2401) showed 22 chaetigers and one pair of genital papillae on CH 8; these characters are also present in Laubieriopsis norvegica Zhadan & Atroshchenko, 2012 (type locality: off Bergen, Norway). However, the latter differs from our specimen in number and features of chaetae, lacking aciculars in median and posterior parapodia, which are provided only with one capillary and one very small and thin additional chaeta in each parapodial ramus ( Zhadan and Atroshchenko 2012; Salazar-Vallejo et al. 2019). Furthermore, BIOICE specimens differ from those reported in Hawaii (Central Pacific) by Magalhães et al. (2014, as cf.) in having parapodial lobes that are more developed, chaetae that are provided with scale covering along its full length and CH 21 chaetae that are longer and recurved backwards. On the contrary, Pacific specimens are small (up to 5 mm in length) and lacking genital papilla, and are provided with chaetae that are smooth basally and distally while covered by rows of spines (‘rings of denticles’) elsewhere; genital papilla is, however, discernible already in BIOICE specimens at least of 4 mm in length.

Figures

Figure 1. Geographical distribution of Fauveliopsidae species found in BIOICE samples. (a) BIOICE samples with fauveliopsids. (b) Fauveliopsis olgae Hartman-Schröder, 1983. (c) Laubieriopsis brevis (Hartman, 1967). (d) Laubieriopsis cabiochi (Amoureux, 1982). (a): blue area marking position of samples with specimens of the three species; (b–d): red areas marking samples/group of samples with high number of specimens; numbers (1–4): marking samples/group of samples with high number of specimens (see also Figure 2).

Figure 2. Values of temperature versus depth for BIOICE samples with Fauveliopsidae specimens. (a) Fauveliopsis olgae Hartman-Schröder, 1983. (b) Laubieriopsis brevis (Hartman, 1967). (c) Laubieriopsis cabiochi (Amoureux, 1982). Numbers as in Figure 1.

Figure 8. Laubieriopsis cabiochi (Amoureux, 1982). SEM micrographs, BIOICE samples 2712 ((a,b); IINH40859), 2282 ((c–e); IINH40828), 2717 ((f); IINH40863) and 2398 ((g); IINH40843). (a) Anterior body region, ventral view. (b) Anterior end, ventral view. (c) Anterior end, dorsal view. (d) Anterior end, dorsal view. (e) Chaetiger 3, detail. (f) Anterior end, ventral view. (d) Anterior end, dorsal view. (e) Chaetiger 3, detail (framed in (a)). (f) Anterior end, ventral view. (g) Chaetigers 1–3, ventral view. Abbreviations: A – acicular chaeta; a – thin acicular chaeta; CH – chaetiger; gp – genital papilla; imp – integumental micropapillae; irp – interramal papilla; isb – intersegmental border; mo – mouth; per – peristomium; pr – prostomium.

Figure 9. Laubieriopsis cabiochi (Amoureux, 1982). SEM micrographs, BIOICE samples 2308 ((a); IINH40834), 2273 ((b,d); IINH40825), 2712 ((c); IINH40859); 2282 ((e); IINH40828); 2398 ((f); IINH40843) and 2272 ((g); IINH40823). (a) Anterior region, parapodium. (b) Anterior region, acicular chaeta showing bifid distal end and scale covering. (c) Chaetigers 8–9, chaetae and genital papilla. (d) Midbody parapodium, chaetae (inset, detail of scale cover). (e) Posterior body end, dorsal view. (f,g) Pygidium, laterodorsal view. Abbreviations: A – acicular chaeta; c – capillary chaeta; CH – chaetiger; gp – genital papilla; imp – integumental micropapillae; irp – interramal papilla; pp – pygidium papillae; pyg – pygidium.