Paramoera dentipleurae, Jung, Tae Won, Kim, Jong Guk & Yoon, Seong Myeong, 2016

Jung, Tae Won, Kim, Jong Guk & Yoon, Seong Myeong, 2016, Two new species of pontogeneiid amphipods (Crustacea, Senticaudata, Calliopioidea) from Korean waters, ZooKeys 635, pp. 53-79 : 59-67

Paramoera dentipleurae sp. n. Figs 7, 8, 9, 10, 11

Type locality.

Jeju Island, South Korea, 33°14'23"N 126°34'59"E, sublittoral (average depth 24 m).

Material examined.

Holotype: NIBRIV0000328602, adult female, 7.6 mm, collected from the type locality on 30 Nov 2012 by Prof. H.-Y. Soh.

Etymology.

The composite epithet of the species name of dentipleurae is a combination of Latin dens, Gen. dentis (meaning ‘teeth’ or ‘serration’) and pleurae (indicating 'pleonal epimera’). Noun in apposition.

Diagnosis.

Head with short rostrum; lateral cephalic lobes not mammilliform, with sinusoid upper part; inferior antennal sinus forming deep notch, lower margin produced forward; eyes large, reniform. Antenna 1 with stout peduncular articles; accessory flagellum uni-articulate, short, scale-like. Antenna 2 slightly shorter than antenna 1. Lower lip outer lobe with 5 bifid setae mediodistally. Right mandible with 6-dentate incisor and bifid lacinia mobilis. Left mandible with 6-dentate incisor and 5-dentate lacinia mobilis. Maxilla 1 outer plate with 10 dentate robust setae apically; palp bi-articulate, apex beyond apical setae of outer plate. Maxilla 2 inner plate shorter than outer plate. Maxilliped outer plate as long as inner plate, with long serrate setae along apex and medial margins submarginally; palp articles 2 and 3 slender. Gnathopods 1 and 2 moderately subchelate. Gnathopod 1 palm oblique, with robust defining setae of 1, 1, 3 laterally and 2, 3, 1 medially in formulae. Gnathopod 2 palm more oblique than in gnathopod 1, with robust defining setae laterally in formula 1, 2, 1. Pereopods 3-7 dactylus short, with blunt protrusion bearing 1 seta on inner margin, apex curved and claw-like. Pereopods 5-7 elongate and slender. Pereopod 7 basis expanded posteriorly, angulate proximally and diminished distally. Pereonite 7 and pleonites 1-3 carinate dorsally. Pleonal epimeron 1 with 2 naked serrations and 1 weak notch posteriorly; epimeron 2 with 2 serrations bearing 1 minute seta and 1 naked notch posteriorly; epimeron 3 largest, weakly upturned posterodistally, with 5 serrations and 1 distal small notch bearing 1 minute seta posteriorly. Uropod 1 slender; peduncle longer than rami. Uropod 2 shortest. Uropod 3 rami lanceolate, longer than peduncle. Telson deeply cleft (approximately 3/4 length).

Description of holotype male.

Head (Fig. 7A): rostrum short; lateral cephalic lobes not mammilliform, with sinusoid upper part; inferior antennal sinus forming deep notch, lower margin produced forward; eyes large, reniform.

Antenna 1 (Fig. 7 B–F): peduncular articles stout, with length ratio of 1.0:0.8:0.5 in peduncular articles 1-3, each article with 4-6 groups of elongate setae along posterior margin; peduncular article 1 with 1 robust seta posterodistally and with small triangular lobe on surface posterodistally; peduncular article 2 also with 1 robust seta posterodistally; peduncular article 3 without posterodistal setae; accessory flagellum uni-articulate, short, scale-like, with 5 simple setae on apex and 1 simple seta anteroproximally; flagellum 33-articulate, 2.0 times as long as peduncular articles 1-3 combined, proximal article longest, with aesthetasc present on every alternate article and calceoli present from 3rd to 24th articles posterodistally.

Antenna 2 (Fig. 7G, H): slightly shorter than antenna 1; gland cone produced with 2 simple setae; peduncular articles stout, with length ratio of 1.0:1.7:1.8 in peduncular articles 3-5; flagellum 29-articulate, 1.6 times as long as peduncular articles 3-5 combined, proximal article longest, with calceoli present from 1st to 20th articles.

Upper lip (Fig. 7I): triangular, apical margin convex, covered with fine setae distally.

Lower lip (Fig. 7J): with well-developed mandibular processes bearing round apices; outer lobe apically round with 5 bifid setae mediodistally; inner lobe weak.

Right mandible (Fig. 7K): with 6-dentate incisor and bifid lacinia mobilis; accessory setal row lined with 1 simple, 5 serrate and 2 simple setae in turn; molar triturative, columnar, with 1 long plumose seta; palp enlarged, 3-articulate; palp article 1 shortest; palp article 2 lined with plumose setae on surface and medial margin; palp article 3 brush-like, with many simple, plumose and serrate setae along apex and medial margin.

Left mandible (Fig. 7L): with 6-dentate incisor and 5-dentate lacinia mobilis; accessory setal row with 1 simple, 7 serrate setae and 1 simple seta in turn.

Maxilla 1 (Fig. 7M, N): outer plate with 10 dentate setae apically; palp long, beyond apical setae of outer plate, article 2 with 1 row of 9 setae on surface and 8 robust setae along apical and mediodistal margins, with 1 plumose and 1 simple seta at centre of lateral margin.

Maxilla 2 (Fig. 7O): inner plate with 1 oblique row of 5 plumose setae on medial margin, with apical and subapical setae; outer plate with 2 serrate and 2 forked setae on mediodistal margin, with apical and subapical setae.

Maxilliped (Fig. 8A): inner plate subrectangular, swollen laterodistally, with 3 robust setae apically, with plumose setae on apex and mediodistal margin; outer plate as long as inner plate, convex laterally and wider than inner plate, with elongate plumose setae along apex and medial margin submarginally; palp elongate, slender, 4-articulate; article 2 subrectangular, longest, lined with long forked and simple setae on medial margin; article 3 thumb-shaped, with forked, serrate and simple setae on distal surface and margin; article 4 falcate, 0.8 times as long as article 3, lined with setae on medial margin, with 1 elongate seta apically.

Gnathopod 1 (Fig. 8B, C): subchelate; coxa subrectangular, ventral margin round with 5 minute setae and with 1 small notch bearing 1 minute seta posteroventrally; basis anterior margin straight with 8 minute setae, with 1 pair of elongate setae on medial surface anteroproximally, posterior margin with 1 elongate seta proximally, lined with 1 group of 4 elongate setae and with 3 minute setae, with 1 group of 3 simple setae subdistally; ischium with moderate anterior lobe, posterior margin convex with 1 simple seta and 1 group of 9 elongate setae; merus rectangular, as long as ischium, forming groove anterodistally, with medial and lateral protrusions distally, with 1 pair of short setae medially, with elongate setae in formula 1, 2, 3, 2 on posterior margin, lined with 14 long setae on distal margin; carpus longer than merus, with 1 lateral row of 5 setae anterodistally and 1 medial row of 5 setae on distal margin, posterior margin broadly lobed and weakly crenulate, with 4 groups of serrate and simple setae; propodus ovoid, as long as basis, with 4 setae on anterior margin, with 1 group of 6 simple setae at anterodistal corner, with 5 groups of serrate setae on weakly crenulate posterior margin, with setae of various combinations on medial surface, palm oblique with medial and lateral rows of simple setae, with robust defining setae of in formulae 1, 1, 3 laterally and 2, 3, 1 medially; dactylus falcate, stout, slightly shorter than palm.

Gnathopod 2 (Fig. 8D, E): also moderately subchelate, similar to gnathopod 1 in size; coxa subrectangular, with 3 minute setae on round ventral margin anteriorly, with 2 small notches posteroventrally, with 7 minute setae on anterodistal surface, coxal gill ovoid and large, slightly shorter than basis; basis anterior margin slightly convex lined with 10 minute setae, posterior margin with 1 elongate setae proximally and 1 group of 3 simple setae (2 elongate and 1 short) at proximal 1/3, lined with 7 simple setae and 1 group of 3 simple setae subdistally at distal half; ischium with moderate anterior lobe, posterior margin convex with 4 setae; merus as long as ischium, forming groove anterodistally, with medial and lateral protrusions distally, with 2 pairs of simple setae on anterior margin medially, with 1 seta and 2 pairs of setae on posterior margin distally, with 6 elongate setae on distal margin; carpus longer than merus, with 1 lateral row of 6 setae anterodistally, posterior margin broadly lobed and weakly crenulate with 5 groups of serrate and simple setae; propodus ovoid, as long as basis, with 4 simple setae on anterior margin, with 1 group of 6 simple setae at anterodistal corner, weakly crenulate posteriorly with 7 groups of serrate setae, palm more oblique than in gnathopod 1, with medial and lateral rows of simple setae, with robust defining setae laterally in formula 1, 2, 1; dactylus falcate, stout, slightly shorter than palm.

Pereopod 3 (Fig. 9A, B): coxa subrectangular, convex anteriorly, with 4 minute setae on anterior surface, ventral margin round with 3 marginal and 5 submarginal setae, with 2 small notches bearing 1 minute seta at posteroventral corner, posterior margin short, coxal gill ovoid and large, as long as coxa; basis anterior margin straight with 4 pairs and 6 minute setae, posterior margin setose; ischium short, with moderate anterior lobe, with 1 minute seta on posterior margin and 1 pair of simple setae at posterodistal corner; merus 0.7 times as long as basis, anterior margin weakly spinose and slightly expanded distally, with 1 group of 3 simple setae at anterodistal corner, posterior margin weakly setose; carpus not expanded and slightly curved, with 2 groups of simple setae on anterior margin and 1 pair of simple setae at anterodistal corner, with 1 minute and 3 pairs of simple setae on posterior margin, with several minute setae at posterodistal corner, distal margin round; propodus slender, 1.1 times as long as carpus, with 3 groups of simple setae on anterior margin and 1 row of 4 setae at anterodistal corner, with 1 small seta and 2 pair of setae on posterior margin, with 1 elongate, 1 robust and 2 moderate setae at posterodistal corner; dactylus short, with blunt protrusion bearing 1 seta on inner margin, apex curved and claw-like.

Pereopod 4 (Fig. 9C, D): coxa subquadrate, with acutely produced posterior margin; dactylus with blunt protrusion on inner margin but weaker than that of pereopod 3; other articles similar to those of pereopod 3 except for additional 1 robust seta at posterodistal corner of basis.

Pereopod 5 (Fig. 10 A–D): elongate and slender; coxa bilobed, anterior lobe expanded downwards with 4 minute setae on ventral margin, posterior lobe not expanded with 1 small notch bearing 1 minute seta at posteroventral corner, coxal gill ovoid and small; basis subovoid, anterior margin convex with 1 group of 5 elongate setae proximally and lined with 7 robust setae, anterodistal corner weakly lobed downwards with 1 pair of robust setae, posterior margin moderately expanded with 13 weak serrations bearing 1 minute seta; ischium short, anterodistal corner weakly lobed downwards with 1 pair of setae, posterior lobe moderate; merus as long as basis, with short robust setae on anterior margin and with 1 pair of robust and simple setae at anterodistal corner, posterior margin weakly expanded and setose with robust setae, posterodistal corner slightly produced with 1 pair of unequal setae; carpus linear and slender, as long as merus, margins weakly setose, anterodistal and posterodistal corners with robust and simple setae; propodus also linear, 0.9 times as long as carpus, with 4 pairs of robust setae on anterior margin and with 1 group of 4 setae (1 simple elongate and 3 robust) at anterodistal corner, with 4 groups of robust and simple setae on posterior margin and with 10 setae (1 robust and 9 simple) at posterodistal corner; dactylus short, with blunt protrusion bearing 1 seta on inner margin, with curved and claw-like apex.

Pereopod 6 (Fig. 10E): elongate and slender, longer than pereopod 5; coxa bilobed, smaller than that of pereopod 5, anterior lobe expanded downwards with 2 minute setae anteriorly, posterior lobe not expanded with notch bearing 1 minute seta at posteroventral corner, coxal gill ovoid and slightly smaller than that of pereopod 5; basis as long as that of pereopod 5, anterior margin convex with 1 elongate seta proximally and irregular spaced 7 robust and simple setae, anterodistal corner weakly lobed downwards with 1 robust seta, posterior margin expanded proximally and diminished distally, with 13 weak serrations bearing 1 minute seta and 2 minute setae distally; ischium short, anterodistal corner weakly lobed downwards with 1 group of 3 setae, posterior lobe moderate; merus as long as basis, setose with robust and simple setae on anterior margin, with 1 pair of setae at anterodistal corner, posterior margin weakly expanded and setose with elongate and short robust setae irregularly, posterodistal corner slightly produced with 1 group of 5 setae; carpus linear and slender, 1.1 times as long as merus, margins weakly setose, anterodistal and posterodistal corners with robust and simple setae; propodus also linear, as long as carpus, with 5 groups of robust and simple setae on anterior margin, and with 1 group of 4 setae (1 simple elongate and 3 robust) at anterodistal corner, posterior margin armed with setae of various combinations, with 9 setae (8 simple elongate and 1 robust) at posterodistal corner; dactylus short, with blunt protrusion bearing 1 seta on inner margin, with curved and claw-like apex.

Pereopod 7 (Fig. 11A, B): shorter but stouter than pereopod 6; coxa unilobed, with 1 simple seta at anterior corner, with 2 notches bearing 1 minute seta and 2 small naked notches on posterior margin; basis larger than that of pereopod 6, anterior margin widened with irregular spaced 8 minute setae, anterodistal corner a little lobed distally with 1 group of 3 robust setae, posterior margin expanded, angulate proximally and diminished distally, with 12 weak serrations bearing 1 minute seta and 2 naked serrations distally; ischium short, anterodistal corner weakly lobed downwards with 1 group of 5 robust setae, posterior lobe moderate; merus short, 0.7 times as long as basis, anterior margin straight and setose with single or paired setae, anterodistal corner weakly produced with 1 subapical simple seta and 1 pair of robust apical setae, posterior margin slightly expanded and setose with irregular elongate and short robust setae, posterodistal corner slightly produced with 1 group of 6 robust setae (1 elongate and 5 moderate); carpus linear, as long as basis, with 5 groups of robust setae on anterior margin and with 1 group of 7 robust setae at anterodistal corner, with 1 single and 5 groups of robust setae on posterior margin and with 1 group of 6 robust setae at posterodistal corner; propodus also linear, as long as carpus, with 5 groups of 3 robust setae on anterior margin and 1 group of 4 setae (1 simple elongate and 3 robust) at anterodistal corner, posterior margin armed with setae of various combinations, with 13 setae (2 robust and 11 simple) at posterodistal corner; dactylus short, with blunt protrusion bearing 1 seta on inner margin, with curved and claw-like apex.

Pereonite 7 and pleonites 1-3 (Fig. 11C): each carinate dorsally.

Pleonal epimera (Fig. 11C): epimeron 1 with 2 naked serrations and 1 weak notch on posterior margin; epimeron 2 round ventrally, with 3 setae on anterior half of ventral margin, with 2 serrations bearing 1 minute seta and 1 naked notch on posterior margin; epimeron 3 largest, weakly upturned posterodistally, with 3 setae on ventral margin, with 5 serrations and 1 distal small notch bearing 1 minute seta on posterior margin.

Uropod 1 (Fig. 11D): slender; peduncle longer than rami, with 14 lateral and 9 medial robust setae dorsally; outer ramus with 6 lateral robust setae dorsally, apex blunt with 2 subapical and 2 apical robust setae; inner ramus shorter than outer ramus, with 6 lateral and 5 medial robust setae dorsally, apex blunt with 2 subapical and 2 apical robust setae.

Uropod 2 (Fig. 11E): shortest; peduncle 0.7 times as long as that of uropod 1, with 9 lateral and 7 medial robust setae dorsally; outer ramus shorter than peduncle, with 4 lateral robust setae dorsally, apex blunt with 2 subapical and 2 apical robust setae; inner ramus subequal to outer ramus, with 4 lateral and 3 medial robust setae dorsally, apex blunt with 2 subapical and 2 apical robust setae.

Uropod 3 (Fig. 11F): peduncle 0.7 times as long as that of uropod 2, with 4 medial and 4 lateral robust setae dorsally; rami lanceolate; outer ramus 2.0 times as long as peduncle, with 4 pairs and 2 single robust setae along lateral margin, with 2 single robust setae, 7 pairs of robust and plumose setae, and 1 minute subapical seta along medial margin; inner ramus slightly longer than outer ramus, with 2 proximal single setae, 7 plumose setae and 1 minute subapical seta on lateral margin, with 1 proximal simple seta, 10 robust and 5 plumose setae on medial margin.

Telson (Fig. 11G): deeply cleft (about 3/4 length), each lobe with notch bearing 1 pair of 1 plumose and 1 long simple seta on apex, with 1 pair of plumose setae on dorsal surface.

Female.

Unknown.

Remarks.

Paramoera dentipleurae sp. n. is very similar to Paramoera tridentata Bulycheva, 1952 and Paramoera hanamurai Hirayama, 1990 in the following characteristics: (1) the anterior cephalic lobe is sinusoid; (2) pereopods 5-7 are more slender than those of other congeners; (3) the posterior lobe of basis on pereopods 6-7 is largely expanded proximally and diminished distally; (4) epimera 1-3 are carinate dorsally; and (5) epimeron 3 is prominently expanded backward with very similar serration pattern on the posterior margin ( Bulycheva 1952; Hirayama 1990). However, Paramoera dentipleurae sp. n. can be readily distinguished from Paramoera tridentata by the following features: (1) the inferior antennal sinus is deeply cleft and its lower part is produced forward in Paramoera dentipleurae sp. n., whereas it is concaved quadrately in Paramoera tridentata ; (2) the formulae of robust defining setae at the palmar corners on gnathopods 1 and 2 are complex in Paramoera dentipleurae sp. n. (1, 1, 3 for lateral and 2, 3, 1 for medial setae on gnathopod 1 and 1, 2, 1 for lateral setae on gnathopod 2), whereas Paramoera tridentata has only two lateral setae on gnathopods 1 and 2, respectively; (3) the serrations of each posterior margin of the basis on pereopods 5-7 are weaker in Paramoera tridentata ; and (4) the dorsal carina on pereon 7 is absent in Paramoera tridentata ( Bulycheva 1952; Labay 2012).

Paramoera dentipleurae sp. n. can be discriminated from Paramoera hanamurai by the following features: (1) upper and lower parts of the inferior antennal sinus do not overlap in Paramoera dentipleurae sp. n.; (2) antenna 1 is longer than antenna 2 in Paramoera dentipleurae sp. n., but antenna 2 is longer than antenna 1 in Paramoera hanamurai ; (3) setations of the peduncular articles on antennae 1 and 2 of Paramoera dentipleurae sp. n. are weaker; (4) accessory flagellum has five apical setae in Paramoera dentipleurae sp. n., but it has only two apical setae in Paramoera hanamurai ; (5) formulae of the robust defining setae at the palmar corners on gnathopods 1 and 2 are different from each other (1, 1, 3 for lateral setae and 2, 3, 1 for medial setae on gnathopod 1, and 1, 2, 1 for lateral setae in gnathopod 2 in Paramoera dentipleurae sp. n., whereas there are three rows of three setae on the medial surface of gnathopod 1 and without setae on gnathopod 2 in Paramoera hanamurai ); (6) posterior margin of basis on pereopod 5 is more expanded distally and the length of the merus is shorter in Paramoera hanamurai ; (7) serration patterns are weaker and the posterodistal lobes are indistinct for basis on pereopods 5-7 in Paramoera dentipleurae sp. n. compared to Paramoera hanamurai ; (8) each dorsal margin from pereon 7 to pleon 3 has a distal carina in Paramoera dentipleurae sp. n., whereas the distal carina is absent in Paramoera hanamurai ; and (9) serration patterns of the posterior margins on the pleonal epimera are simpler in Paramoera hanamurai compared to those in Paramoera dentipleurae sp. n. ( Hirayama 1990).