Maxilliclausia propria Kim 2014, n. sp.

Maxilliclausia propria n. sp. (Figs. 7, 8)

Material examined. 2 from washings of polychaetes (mixing of several species) collected from a tidal flat (34 49′54′′N, 128 02′08′′E), Namhae Island, on the southern coast of Korea, 21 June 2012. Holotype (intact NIBRIV0000286630) has been deposited in the National Institute of Biological Resources (NIBR), Incheon, Korea. Dissected paratype () is retained in the collection of the author.

Female. Body (Fig. 7A) cylindrical, consisting of cephalothorax, second to fifth pedigerous somite, genital somite, and 4 abdominal somites. Body length 2.75 mm in dissected paratype. Somites from cephalothorax to genital somite not articulated from one another but well defined by deep constrictions between them and with convex lateral margins. Sizes of cephalothorax to fifth pedigerous somite 523

431 Μm, respectively. Cephalothorax nearly trapezoid, broadening distally, with rounded posterolateral corners and nearly circular dorsal sclerotization band. Fifth pedigerous somite subcircular, longer and broader than preceding metasomal somites. Genital somite 217 433 Μm, much wider than long; lateral margins projected laterally and tapering; genital aperture large and locating dorsolaterally. Abdomen distinctly narrower than anterior part of body, smooth, and well-segmented; four abdominal somites 192 192, 196 175, 150 158, and 175 154 Μm, respectively. Anal somite lacking anal operculum (Fig. 7B). Caudal ramus (Fig. 7C) 102 50 Μm (ratio 2.04: 1), with 6 naked setae; one (seta V) of 2 median terminal setae much larger than other 5 setae, about twice as long as second largest nearby seta (seta IV). Egg sac (Fig. 7D) 1.33 0.36 mm, containing multiserial eggs; each egg about 190 Μm in diameter.

[table omitted]

Rostrum as broad apical protuberance of cephalothorax, truncated apically, and not articulated at base (Fig. 7A). Antennule (Fig. 7E) distinctly narrowing distally, 307 Μm long, and 6-segmented, but suture line between second and third segment indistinct and existing only on dorsal surface; armature formula 4, 11, 7, 4, 2+aesthetasc, and 7+aesthetasc; all setae naked; aesthetascs on 2 distal segments shorter than their accompanying setae. Antenna (Fig. 7F) 4-segmented, consisting of coxa, basis, and 2- segmented endopod; coxa short, much broader than long, and unarmed; basis with large outer protrusion ornamented apically with about 15 foliaceous, tapering processes, and with 1 small medio-distal seta; first endopodal segment about 94 Μm, with large, corrugated adhesion pad on medial surface and 1 outer subdistal seta; second endopodal segment 88 32 Μm, broadest at proximal 2/5 region, blunt distally, with large, corrugated adhesion pad along medial surface, and 5 (3 large and 2 small) setae on outer side.

Labrum (Fig. 8A) characteristically with large, digitiform posteromedian process extending to posterior region maxilla (Fig. 7G). Mandible (Fig. 8B) slender, 53 Μm long (excluding distal spine), and armed distally with 1 elongate, rod-shaped spine of 83 Μm long; this distal spine blunt at tip, with about 16 small teeth along distal 2/5 of outer margin. Paragnath absent. Maxillule (Fig. 7H) lobate, armed with 3 unequal outer setae and 1 small medial seta; distal part of maxillule expanded and forming large adhesion pad. Maxilla (Fig. 8C) 2-segmented; proximal segment elongated, unarmed but with large patch of spinules on posterior surface (Fig. 7G); distal segment stout and forming an sucking disc bearing 1 small seta anterodistally and corrugated adhesion rim along dorsodistal margin of disk. Maxilliped absent.

Legs 1 and 2 (Fig. 8D, E) biramous, with 2-segmented rami; coxa lacking inner seta, but with 1 row of minute spines on ventral (anterior) surface near distal margin; both sides of intercoxal sclerite roundly projected, with several rows of minute setules. Basis of leg 1 with large pinnate outer seta and 3 transverse rows of minute setules on ventral surface. Basis of leg 2 with smaller, naked outer seta and 2 transverse rows of minute setules on ventral surface. Rami of legs 1 and 2 with several longitudinal rows of minute setules along outer surface. Outer setae on exopod of legs 1 and 2 small. Leg 3 (Fig. 8F) as broad lobe tipped with 3 naked setae, medial one of which being thick. Leg 4 absent. Armature formula of legs 1 and 2 as follows:

Leg 5 (Fig. 8G) represented by 2 naked setae (1 thick and 1 slender). Leg 6 represented by 1 minute seta in genital aperture (Fig. 8H).

Male. Unknown.

Etymology. The specific name propria is derived from the Latin proprius (=peculiar), referring to the possession by the new species of the several unusual morphological features.