Macellicephala linseae

Neal, Lenka, Brasier, Madeleine J. & Wiklund, Helena, 2018, Six new species of Macellicephala (Annelida: Polynoidae) from the Southern Ocean and south Atlantic with re-description of type species, Zootaxa 4455 (1), pp. 1-34: 27-29

publication ID

https://doi.org/10.11646/zootaxa.4455.1.1

publication LSID

lsid:zoobank.org:pub:70E92EDF-E11B-40A7-9573-0AC9F10E623E

persistent identifier

http://treatment.plazi.org/id/03BDA104-A33C-6941-FF64-FF3AFB1C26E9

treatment provided by

Plazi

scientific name

Macellicephala linseae
status

sp. nov.

Macellicephala linseae  sp. nov.

( Figure 2H View Figure , Figure 15B, E, F View Figure and Figures 16 View Figure , 17 View Figure ; Table 2.)

Macellicephala  sp. in Brasier et al. (2016) [record].

Macellicephala  sp. A in Neal et al. (2017) [record].

Material examined. Holotype, NHMUKAbout NHMUK.2018.9354, Amundsen Sea , Southern Ocean, cruise JR 179, station BIO5View Materials  - EBS-2A, collected on 09/03/2008, epibenthic sledge epi-net, 73°52'46.704''S, 106°19'6.456''W, 1052 m depth. DNA vouchers (2 specimens): NHMUKAbout NHMUK.2018.9355, Amundsen Sea , Southern Ocean, cruise JR 179, station BIO5View MaterialsGoogleMaps  - EBS-2A, collected on 09/03/2008, epibenthic sledge, epi-net, 73°52'46.704''S, 106°19'6.456''W, 1052 m depth; NHMUKAbout NHMUK.2018.521, Amundsen Sea , Southern Ocean, cruise JR 179, station BIO5View MaterialsGoogleMaps  -EBS-3D, collected on 10/ 03/2008, epibenthic sledge, epi-net, 73°58'40.152''S, 107°25'0.372''W, 550 m.

Description (based on holotype). Small to medium sized species; holotype with 18 segments (segment 1 = tentacular segment), 8.5 mm long, 1.3 mm wide excluding parapodia and 2.5 mm wide including parapodia. Live specimens not observed. Preserved specimen creamy yellow in colour ( Fig. 16A–C View Figure ).

Prostomium bi-lobed, with a deep anterior notch; prostomial lobes short (not extended), anteriorly rounded ( Fig. 16B View Figure , Fig. 2H View Figure ). Frontal filaments absent. Eyes absent. Ceratophore of median antenna large, inserted in anterior notch ( Figs. 2H View Figure and 16B View Figure ); style of median antenna missing. Palps very long (extending to segment 9), very slender (only slightly thicker than tentacular cirri), smooth, tapering into slender tips.

Tentaculophores inserted laterally to prostomium, of equal size, achaetous ( Fig. 2H View Figure ); only ventral tentacular styles remain attached in holotype, but dorsal styles observed in DNA voucher NHMUKAbout NHMUK.2 0 18.9355, tentacular styles smooth, very slender and very long (extending to segment 9) ( Fig. 16A View Figure ). Facial tubercle absent. Everted pharynx with 2 pairs of jaws and 9 pairs of small triangular papillae ( Fig. 16A View Figure ); each jaw with single fang and smooth margin.

Nine pairs of knob-like elytrophores present on segments 2, 4, 5, 7, 9, 11, 13, 15 and 17; elytra missing.

Cirrigerous segments without dorsal tubercles; distinct dorsal cirrophores elongated, cylindrical to slightly bulbous; styles of dorsal cirri missing. Dorsal ridges appears faintly from segment 3 becoming obvious by segments 5–6, on segments 8–10 forming an oval structure, in segments anterior to segment 8 and posterior to segment 10 forming concentric structures ( Fig. 16C View Figure ). In posterior part of body only, similar ridges appear on parapodia of cirrigerous segments; first parapodial ridge lateral to dorsal ridge, second parapodial ridge near base of cirrophore.

Parapodia biramous. Notopodia reduced to one stout acicula ( Fig. 17A View Figure ). Neuropodia large ( Fig. 17A View Figure ), elongated, subtriangular to rectangular in shape, with integument covered acicula protruding into slender tip; prechaetal and postchaetal lobes poorly developed. Ventral cirrus on segment 2 inserted basally, where very slender and long, approaching tip of neuropodial acicula lobe; inserted medially on subsequent segments where short (much shorter than tip of neuropodial lobe) ( Fig. 17A View Figure ).

Notochaetae stout ( Fig. 17A, C, D View Figure ), few (only 1 to 2 per ramus observed in holotype), often broken off and missing entirely (observed in only 4 parapodia in holotype), short, straw-coloured, with distinct horizontal striation throughout length of its shaft ( Fig. 17 C, D View Figure ), with large rose-bush like alternating and interlocking spines on one side only, distal tip of notochaetae smooth and blunt. Neurochaetae short to very long, numerous, translucent, of two forms: either wide and flattened with shallow, but distinct denticles on both sides throughout most of their lengths, with pointed tip ( Fig. 17B View Figure ) or slender chaetae, with distinct alternating denticles and blunt tip (few in number and easily overlooked) ( Fig. 15F View Figure , marked by arrow and Fig. 17B View Figure ).

Nephridial papillae globular, present at ventral junction of neuropodia and body on segments 10, 11 and 12, inconspicuous in other segments, present from segment 5. Reduced parapodia of segment 18 lateral to pygidium, consisting of notopodia only. Pygidium rounded. Anal cirri not observed.

Remarks. See remarks under Macellicephala gloveri  sp. nov. for further details and differentiation of M. linseae  sp. nov. from similar species M. gloveri  sp. nov. and M. aciculata  .

Molecular Information. COIAbout COI and 16S were sequenced by Brasier et al. (2016), while 18S (452 bp) was obtained in this study ( Table 1). Based on COIAbout COI, this species was closest to Macellicephala gloveri  sp. nov. with K2P distance 0.12 and uncorrected 'p' distance 0.11.

Etymology. This species is named after Dr. Katrin Linse from the British Antarctic Survey, leading Antarctic researcher and the principal scientist of BIOPEARL II cruise.

Distribution. Pine Island Bay, Amundsen Sea at shelf and slope depths of 550 to 1052 m.

NHMUK

Natural History Museum, London

COI

University of Coimbra Botany Department