Melinna cristata ( Sars, 1851 ) Melinna albicincta Mackie & Pleijel, 1995

Gunton, Laetitia M., Zhang, William, Kupriyanova, Elena K. & Hutchings, Pat A., 2023, New Species of Melinna (Melinnidae, Annelida) from the Australian Abyss with Comments on M. albicincta, M. cristata and M. elisabethae, Records of the Australian Museum (Rec. Aust. Mus.) 75 (3), pp. 125-154 : 135-137

publication ID	https://doi.org/ 10.3853/j.2201-4349.75.2023.1803
DOI	https://doi.org/10.5281/zenodo.10982408
persistent identifier	https://treatment.plazi.org/id/03A9585E-FFC2-FFDA-5FBD-D5CB65D0F81F
treatment provided by	Felipe
scientific name	Melinna cristata ( Sars, 1851 ) Melinna albicincta Mackie & Pleijel, 1995
status

Treatment

Melinna cristata ( Sars, 1851) View in CoL

Figs 9–12 View Figure 9 View Figure 10 View Figure 11 View Figure 12 ; Tables 4, 5

Sabellides cristata M. Sars, 1851: 205–206 ; 1856: 19–23, pl. 2, fig. 1–7.

Melinna albicincta Mackie & Pleijel, 1995 View in CoL

Melinna cristata Malmgren, 1866: 371–372 View in CoL , pl. 20, fig. 50.

For complete synonymy see Mackie & Pleijel, 1995.

Figs 6–8 View Figure 6 View Figure 7 View Figure 8 ; Tables 4, 5

Material examined. AM W.21791, 3 specimens, including one prepared for SEM ( AM W.21791.001), west of Salto , Kosterfjord, Sweden (59°00'N 11°00'E), mud, 110 m, coll. A. S. Mackie & F. Pleijel, 26 October 1989 GoogleMaps .

Melinna albicincta Mackie & Pleijel, 1995: 116–120 View in CoL , fig. 3, 5, table 1.

Material examined. Paratypes NMWZ1989125 View Materials 26 View Materials , one mounted for SEM, NMWZ1989125 View Materials 22 View Materials , type locality Southwest of Yttre Vattenholmen , Kosterfjord, Sweden (58°52'30"N 11°06'18"E), sand/mud/gravel, dredged from 60–80 m, coll. A.S. Mackie & F. Pleijel, 28 October 1989 GoogleMaps . AM W.21794, 1 specimen, collected same locality, same date, same collectors, sandy mud/stones/gravel, 40–50 m, dredge. In Mackie & Pleijel, 1995 this paratype is listed as GoogleMaps AM W.21791, this is incorrect, the correct registration number for this specimen is AM W.21794.

Remarks

The redescription by Mackie & Pleijel (1995) only provided line drawings, here we give additional information based on light and SEM photographs.

Prostomium with welldefined anterior and posterior parts followed by an achaetous segment 1 with anterior elevated margin ( Fig. 9A,B View Figure 9 ). Segments 2–5 with short row of acicular neurochaetae progressively becoming more laterally inserted ( Fig. 9B View Figure 9 ). From segment 6 onwards neuropodia with uncini on raised tori ( Fig. 11D View Figure 11 ). Notopodia present from segment 4 (chaetiger 3), very small with few notochaetae, gradually increasing in size and becoming conspicuous and laterally arranged by segment 7 onwards ( Figs 9D View Figure 9 , 10G View Figure 10 , 11D View Figure 11 , 12A,B,C View Figure 12 ). Notopodia bearing two tiers of notochaetae with finely spinulose surface ( Fig. 11A,B View Figure 11 ). Dorsal membrane with at least 8 equal triangular projections ( Figs 10B View Figure 10 , 11C View Figure 11 ). A single pair of slightly curved dorsal hooks with prominent internal canal ( Fig. 10B,C,D,E View Figure 10 ). Four pairs of branchiae ( Fig. 10A,E View Figure 10 ), annulated with distinct longitudinal bands of cilia ( Fig. 10F View Figure 10 ) and fused basally for about 10% of their length ( Figs 9C,D View Figure 9 , 10A,E View Figure 10 , 11D View Figure 11 ). Thoracic neuropodia ( Fig. 11D,E View Figure 11 ) raised, glandular tori with over 40 uncini, uncini with a single row of 3–4 teeth and a subrostral ornamented process ( Fig. 11F,G View Figure 11 ). Rudimental notopodia on the abdomen as small rounded projections ( Fig. 9F View Figure 9 ). Abdominal segments with elevated neuropodia decreasing in size posteriorly ( Fig. 9E View Figure 9 ). Abdominal uncini with rostral tooth surrounded by strongly denticulated head ( Fig. 12D,E View Figure 12 ). Pygidium with terminal anus, bounded by glandular lobes ( Figs 9E,e View Figure 9 , 12F,G View Figure 12 ) with no anal cirri. Methyl blue staining shows extensive ventral and lateral thoracic glandular areas ( Fig. 9A,E View Figure 9 ). No tube present.

Remarks

The original description only provided line drawings, here we give additional information based on light and SEM photographs.

Prostomium with two elongate transverse nuchal slits ( Fig. 6A,B View Figure 6 ). The first segment achaetous, forming a ventral collar with an elevated crenulated anterior margin ( Fig. 6D View Figure 6 ). Segments 2, 3, 4 and 5 with neurochaetae as short acicular spines with neuropodia becoming more lateral, on segment 6 elongated raised tori with neurochaetae as uncini ( Figs 6D View Figure 6 , 7B View Figure 7 ). First notopodia on segment 4, very small with short capillary chaetae, and gradually becoming more dorsal and better developed by segment 6 with two tiers of capillary chaetae (as seen in chaetiger 11, Fig. 7C View Figure 7 ). This numbering of anterior segments differs from that given by Mackie & Pleijel (1995) as they did not recognize an achaetous segment 1 which forms a ventral glandular collar ( Fig. 6D View Figure 6 ). Pair of short dorsal curved hooks ( Fig. 6E, F View Figure 6 ). Four pairs of elongate branchiae ending in tapered pointed tips ( Fig. 6A,D,E View Figure 6 ), with inner and anterior most pair basally fused (35–40%) (Figs 6E, 7E,F); two conspicuous white bands present on inner pairs ( Fig. 6A,B View Figure 6 ) but absent on other branchiae. Segment 5 with dorsal membrane ( Fig. 7E View Figure 7 ) bearing large number of small projections. Larger middorsal papilla beneath dorsal membrane ( Figs 6E View Figure 6 , 7E,F View Figure 7 ), as also shown in Fig. 5A View Figure 5 of Mackie & Pleijel (1995). Ventrum with anterior margins of segments elevated and glandular ( Fig. 7A View Figure 7 ). Notopodia with elevated lobes and notochaetae arranged in two tiers ( Fig. 8A,D View Figure 8 ). Anterior neuropodia forming raised tori with uncini arranged in a curved row ( Fig. 7B View Figure 7 ), with four teeth in longitudinal row on chaetiger 11 and 13 ( Figs 7D View Figure 7 , 8B View Figure 8 respectively). Rudimental notopodia on the abdomen as small rounded projections ( Fig. 6C View Figure 6 ). Mid and posterior neuropodia becoming increasingly elevated ( Fig. 8A,F View Figure 8 ). Abdominal uncini with four teeth in a longitudinal row ( Fig. 8B,C,E View Figure 8 ). Pygidium with terminal anus and surrounded by a pair of large lateral lobes and a number of smaller ones ( Fig. 8F View Figure 8 ). Living in muddy tube with attached shell fragments ( Fig. 6G View Figure 6 ).

This numbering of anterior segments differs from that given by Mackie & Pleijel (1995) as they did not recognize an achaetous segment 1 forming a ventral glandular collar ( Fig. 11D View Figure 11 ).