Laonice grimaldii Sikorski, Nygren & Mikac, 2021

Sikorski, Andrey V., Radashevsky, Vasily I., Castelli, Alberto, Pavlova, Lyudmila V., Nygren, Arne, Malyar, Vasily V., Borisova, Polina B., Mikac, Barbara, Rousou, Maria, Martin, Daniel, Gil, João, Pacciardi, Lorenzo & Langeneck, Joachim, 2021, Revision of the Laonice bahusiensis complex (Annelida: Spionidae) with a description of three new species, Zootaxa 4996 (2), pp. 253-283 : 269-273

publication ID	https://doi.org/ 10.11646/zootaxa.4996.2.2
publication LSID	lsid:zoobank.org:pub:9FF4827B-A424-4D02-A58D-2CB37E1FAB5A
DOI	https://doi.org/10.5281/zenodo.5069840
persistent identifier	https://treatment.plazi.org/id/D21FC5F2-B9E2-4840-B75F-2D24EBBC2F45
taxon LSID	lsid:zoobank.org:act:D21FC5F2-B9E2-4840-B75F-2D24EBBC2F45
treatment provided by	Plazi
scientific name	Laonice grimaldii Sikorski, Nygren & Mikac
status	sp. nov.

Treatment

Laonice grimaldii Sikorski, Nygren & Mikac View in CoL n. sp.

http://zoobank.org:act: D21FC5F2-B9E2-4840-B75F-2D24EBBC2F45

( Figs 10 View FIGURE 10 , 11 View FIGURE 11 , 12A–C View FIGURE 12 , 13 View FIGURE 13 , 14A View FIGURE 14 , 18C View FIGURE 18 , 19B View FIGURE 19 , Table 3)

Aonides cirrata: Fauvel, 1909 (Part.) : 4–5. Not M. Sars 1851.

Laonice cirrata: Fauvel, 1927 (Part.) View in CoL : 37–38, fig. 12a–e. Not M. Sars 1851.

Type locality. ITALY, Ligurian Sea , st. GAS 10 View Materials ter., 43.6368°N, 10.0983°E, 70–80 m, muddy sand GoogleMaps .

Type material. MOM INV-0022706 (holotype) , INV-0022681–0022693 , 0022698 , 0022699 (35 paratypes) ; HUJI NVPOLY-2950 (4 paratypes) ; MIMB 39037–39039 View Materials , 39047 View Materials (23 paratypes) ; MNCNM 16.01 /18549–18566 (144 paratypes) .

Adult morphology. Holotype largest complete specimen 40 mm long, 0.8 mm wide for 109 chaetigers. Smallest complete paratype 13 mm long, 0.26 mm wide for 61 chaetigers. Pigmentation absent on body and palps. Gatherings of glandular cells on branchiae and postchaetal lamellae appearing dark in some formalin-fixed specimens.

Prostomium triangular, anteriorly wide, truncate or broadly rounded, fused with anterior margin of peristomium ( Figs 10A, B, F View FIGURE 10 , 12A View FIGURE 12 ), extending posteriorly to chaetiger 37 (to end of chaetiger 33 in holotype) as a low caruncle ( Figs 10A View FIGURE 10 , 12A View FIGURE 12 ), shorter in small individuals ( Fig. 13A View FIGURE 13 ). Posterior end of caruncle flat and often indistinct ( Fig. 12B View FIGURE 12 ). Nuchal organs U-shaped ciliary bands on sides of caruncle ( Fig. 10A View FIGURE 10 ). Length of nuchal organs was strongly correlated with individual number of branchiate chaetigers ( Fig. 13C, r View FIGURE 13 2 View FIGURE 2 = 0.8927, n = 30). Occipital antenna present, usually small ( Fig. 10A, B, F View FIGURE 10 , 12A View FIGURE 12 ). One pair of medium-sized median eyes as transverse short wide bands or oblong oval spots oriented obliquely ( Figs 10A, F View FIGURE 10 , 12A View FIGURE 12 ). Palps as long as 10–14 chaetigers, with deep frontal longitudinal groove lined with cilia.

Chaetiger 1 with short capillaries and moderate sized postchaetal lamellae in both rami. Capillaries in each anterior parapodium arranged in two vertical rows. All notopodia with capillary chaetae only. Notopodial postchaetal lamellae with pointed upper tips usually on 3–4 anterior chaetigers ( Fig. 10A View FIGURE 10 ), occasionally on 5–9 anterior chaetigers ( Fig. 11A–D View FIGURE 11 ), with rounded to truncate upper edge on succeeding chaetigers ( Fig. 11E, F View FIGURE 11 ). Notopodial postchaetal lamellae of chaetiger 3 slightly larger than those of chaetiger 4. Notopodial lamellae and branchiae on anterior chaetigers usually overlapping middorsally, thus obscuring observation of nuchal organs. Notopodial postchaetal lamellae on last branchiate chaetiger and on about seven succeeding postbranchial chaetigers with lower part expanded ventrally ( Fig. 11G View FIGURE 11 ). Neuropodial postchaetal lamellae until chaetiger 4 with upper part acute ( Fig. 11A, B View FIGURE 11 ), on succeeding chaetigers with rounded edges ( Fig. 11C–G View FIGURE 11 ).

Branchiae from chaetiger 2 to chaetigers 12–45 (on chaetigers 2–38 in holotype), fewer in smaller individuals ( Fig. 13A View FIGURE 13 ). Branchiae short on anterior chaetigers, full-sized and slightly longer than notopodial postchaetal lamellae from chaetigers 4–5 onwards ( Fig. 11B–F View FIGURE 11 ). Individual number of branchiae was strongly correlated with length of nuchal organs ( Fig. 13C View FIGURE 13 ).

Dorsal transverse crests absent on chaetigers with nuchal organs ( Fig. 12B View FIGURE 12 ). Two dorsal crests usually present on each of 2–3 last branchiate chaetigers ( Fig. 10D View FIGURE 10 ). Anterior crest on each of those chaetigers appearing as an extension of posterior sides of lateral interneuropodial pouches onto dorsum ( Fig. 10C, D View FIGURE 10 ), becoming prominent from chaetiger 16 ( Fig. 10C View FIGURE 10 ) and forming complete dorsal crests on 3–4 last branchiate chaetigers ( Fig. 10D View FIGURE 10 ). Posterior crests appearing 1–2 chaetigers after first start of anterior crests and interconnecting notopodial postchaetal lamellae ( Fig. 10D View FIGURE 10 ). Anterior and posterior crests almost equal in maximum height on 2–3 last branchiate chaetigers. Anterior crests reduced in height on succeeding chaetigers and disappearing completely after 2–6 postbranchiate chaetigers. Posterior crests on approximately 20 postbranchiate chaetigers (until chaetiger 57 in holotype) becoming nearly as high as notopodial postchaetal lamellae.

Lateral interneuropodial pouches from chaetigers 7–26 (from chaetiger 14 in holotype) to body end. Anterior start of pouches was moderately correlated with individual number of branchiate chaetigers ( Fig. 18C, r View FIGURE 18 2 View FIGURE 2 = 0.5278, n = 29).

Sabre chaetae in neuropodia from chaetigers 8–18 (from chaetiger 15 in holotype), from more anterior chaetigers in smaller individuals ( Fig. 13B View FIGURE 13 ), 1–2 in a tuft below vertical row of capillaries or hooded hooks ( Fig. 11F, G View FIGURE 11 ). Anterior start of sabre chaetae was weakly correlated with individual number of branchiate chaetigers ( Fig. 13D, r View FIGURE 13 2 View FIGURE 2 = 0.2854, n = 30).

Hooded hooks in neuropodia from chaetigers 13–36 (from chaetiger 34 in holotype), from more anterior chaetigers in smaller individuals ( Fig. 13B View FIGURE 13 ), up to 13 in a series ( Fig. 11G View FIGURE 11 ). Hooks tri- or quinquedentate, with one or two pairs of small apical teeth above main fang ( Figs 11H View FIGURE 11 , 12C View FIGURE 12 ); superior pair of teeth tiny and hardly discernible, not developed in some hooks. Anterior start of hooks was strongly correlated with individual number of branchiate chaetigers ( Fig. 13D, r View FIGURE 13 2 View FIGURE 2 = 0.9189, n = 31).

Pygidium with one pair of short ventral cirri and up to four pairs of longer and thinner thread-like dorsal cirri with swollen bases ( Fig. 10E View FIGURE 10 ).

Digestive tract without gizzard-like structure.

Methylene green staining. Intensely stained narrow band along frontal edge of prostomium and peristomium ( Fig. 10F View FIGURE 10 ); usually stained as well the posterior surfaces, lateral margins and sometimes frontal surfaces of distal parts of notopodial postchaetal lamellae from chaetiger 4 to chaetiger 9 (rarely up to chaetiger 19), and basal parts of pygidial cirri ( Fig. 10F View FIGURE 10 ). Characteristic diffused staining on ventral body surface, most intensely from approximately chaetiger 21 to chaetigers 33–35 ( Fig. 10G View FIGURE 10 ).

Remarks. Adult L. grimaldii n. sp. appear similar to L. bahusiensis in having the prostomium fused with the frontal margin of the peristomium, dorsal crests only on postbranchiate chaetigers and a narrow band along the frontal edge of prostomium stained with Methylene Green. They differ from all other species of Laonice in having double dorsal crests on chaetigers near the last branchiate chaetiger. Within the L. bahusiensis complex, L. grimaldii n. sp. differs from the other species in having rounded instead of acute notopodial postchaetal lamellae after chaetigers 4–9, and branchiae being slightly longer instead of considerably longer (from 1.3 to 2 times longer) than notopodial postchaetal lamellae. Moreover, the adults of L. grimaldii n. sp. characteristically have a caruncle flattened and therefore indistinct on its posterior end ( Fig. 12B View FIGURE 12 ), contrary to adults of most other species, which have distinct caruncles that terminate clearly and abruptly.

The adults of L. grimaldii n. sp. are similar to those of L. antipoda Sikorski, 2011 from South Africa in various numeric characteristics, especially in the presence of branchiae and prominent dorsal crests on several chaetigers posterior to nuchal organs. In the original description of L. antipoda, Sikorski (2011) noticed the absence of an occipital antenna in the specimens examined but assumed that it might be due to damage. Recent examinations of additional material of L. antipoda from Angola and Gabon (Sikorski, unpublished), however, confirmed the lack of an occipital antenna in this species ( Fig. 12D View FIGURE 12 ). Thus, L. grimaldii n. sp. differs from L. antipoda by having smaller adults (maximum body width ≤ 0.8 mm in L. grimaldii n. sp. versus ≥ 1.0 mm in L. antipoda ), double dorsal crests on 1–2 last branchiate chaetiger(s), an occipital antenna on the prostomium, and notopodial postchaetal lamellae of chaetiger 4 smaller than those of chaetiger 3 (instead of much bigger as in L. antipoda ).

Etymology. The name of the species refers to the House of Grimaldi, the princely family of Monaco and, more specifically, it is dedicated to Prince Albert I, who collected some of the specimens used for the present species description.

Distribution. Mediterranean Sea ( Fig. 14A View FIGURE 14 ). At 4–80 m depth.