Claviderma compactum Ivanov & Scheltema 2008, n. sp.
Creators: name: Ivanov, Dmitry L.
name: Scheltema, Amélie H.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Caudofoveata
Chaetodermatida
Prochaetodermatidae
Claviderma
Claviderma compactum

description: Claviderma compactum n. sp.   
(Figures 1C, 7, 8, 13A, B; Table 5)  
 Type material: Holotype USNM 1112622. Paratypes: USNM; TAMU; ZMUM Le1–172 (type locality); Le1–173 (AII-60 239); Le1–174 (AII-60 239); Le1–175 (AII-60 240); Le1–176 (AII-60 262).   
 Type locality: Argentine Basin, 36°12.7'S, 52°42.7'W, 2,041 m (RV Atlantis II Cruise 60, station 264, 28.03.1971).   
 Material examined: Argentine Basin, 687 specimens (Table 5).   
 Diagnosis: A small Claviderma species <3 mm, shank short, fuzzy from long upright sclerites, <1/3 trunk length, appearing nearly same width as trunk, sclerites upright on an anteroventral bulge, dorsal and remaining ventral trunk sclerites adpressed, at 45º to longitudinal body axis; shank clearly demarcated from trunk but not from knob; fringing sclerites not in ring, scarcely extending beyond knob; knob with two lateral groups of long sclerites. Oral shield sclerites in 3 rows. Trunk sclerites straight, narrow, base long, tapered proximally, blade short, narrower than base, with straight tapered sides ending in sharp point.   
 Etymology: L. compactus, -a, -um = compact.   
 Description: External appearance (Figs 1C, 7A–C): General: Small, trunk smooth, sclerites raised on shank giving it fuzzy, wide appearance; holotype length 2.7 mm, anterium 0.1 mm, trunk 1.6 x 0.6 mm, shank 0.6 X 0.4 mm, knob 0.4 mm, posterium/trunk index 0.37; base of large jaws within hemocoele forming an anteroventral bulge raising sclerites upright (Fig. 7A–C, arrows); trunk sclerites arranged from anteroventral to dorsoposterior, diverging from ventral midline rather far posteriorly but not converging dorsally. Oral shield 0.18 mm in height.   
 Sclerites (Figs 7D, G, 8): General: Blade very short above waist on anterodorsal trunk, lengthening gradually posteriorly to the shank, thickest medially on base of trunk sclerites, thick for size of sclerites. Oral shield (Fig. 7D, 8A): triangular with rounded, angular base, rounded distally, thickest proximally, 65 x 30 x> 3 µm; of nearly equal size in the 3 rows, largest dorsally. Dorsal to oral shield (Fig. 8B): oval or with waist, 50 x 25 x 2 µm. Anterium (Fig. 8C): asymmetrical and deeply waisted, to 100 x 25 x 3 µm. Trunk beneath anteroventral bulge (Fig. 8D): 2 types, one with deep waist like anterium sclerites, the other ovoid with a short blade, to 110 x 30 x 5 µm, thickest medially on base. Ventral trunk posterior to bulge (Fig. 8E, F): like second type of sclerites beneath bulge, but larger and with longer blades,>200 x 40 x 7 µm, thickest medially or distally on base. Dorsal trunk sclerites from anterior to posterior (Fig. 8G, H): similar to ventral sclerites, width of base nearly the same throughout trunk, base and blade both increasing in length, with blade increasing from 1/7 to 1/4 total length, from 150 x 30 x 4 µm to 250 x 35 x 8 µm, thickest medially on base. Shank (Fig. 8I): 2 types, one type with shape like trunk sclerites but with longer blade up to 1/2 total length, to 280 x 30 x 8 µm, thickest on blade; the second type shorter with a wide quadrate base, base and blade of about equal length, to 220 x 60 x 7 µm, thickest medially on blade. Fringe (Fig. 8J): with quadrate base and blade about 3 times length of base, 360 x 50 x 10 µm, or needle-like, 340 x15 x 8 µm. Knob (Fig. 8K): short, straight, tapered or swollen proximally, to 210 x 20 x 4 µm, or very long and hair-like, to 500 x <5 µm.   
 Radula and jaws: 2 examined. Jaws 520 x 200 µm (Fig. 7E); radula teeth 140 µm long, serrated membrane about 90 µm long, medial; central plate symmetrical, curved, 30 x 10 µm (Fig. 7F).   
 Distribution (Fig. 25, Table 5): Known from 5 stations in the Argentine Basin at just above to within the continental rise (993–3,343 m) (Table 5).   
 Remarks: Cl. compactum is distinguished from other Claviderma species by: a wide and fuzzy short shank and small size; 3 rows of oral shield sclerites almost equal in size; short, and narrow sclerite blades with straight sides tapering to a narrow proximal end. The anatomy of the relationship between jaws and hemocoele is found in Scheltema (1981).
description: Published as part of Ivanov, Dmitry L. & Scheltema, Amélie H., 2008, NMR solution structures of KAP- 1 PHD finger-bromodomain, pp. 1-60 in Zootaxa 1885 on pages 14-15, DOI: 10.13018/bmr11036, http://zenodo.org/record/5133706