Oedicerina teresae, Jażdżewska & Brandt & Arbizu & Vink, 2022

Jażdżewska, Anna M., Brandt, Angelika, Arbizu, Pedro Martínez & Vink, Annemiek, 2022, Exploring the diversity of the deep sea-four new species of the amphipod genus Oedicerina described using morphological and molecular methods, Zoological Journal of the Linnean Society 194, pp. 181-225 : 193-199

OEDICERINA TERESAE JAżDżEWSKA, SP. NOV.

( FIGS 7–12 )

Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: 8B11C501-328E-4F33-AA78-F2229D4847A1.

Type material

Holotype: Immature ♂, 5.5 mm, body remnants and two slides with appendages, ZMH K-60661 , DSB_3680, St. Ma 16–25, 11°49.143’ N, 116°58.492’ W- 11°49.975’ N, 116°57.797’ W; 4107– 4101 m, 29 April 2016, leg. Annika Janssen.

Allotype: Mature ♀ (oostegites setose, no egg), 5.8 mm, ZMH K-60662 , DSB_3818, St. AB2-EB12, 12°02.72’ N, 117°25.43’ W- 12°03.03’ N, 117°24.28’ W; 4223–4299 m, 16 March 2015, leg. Inga Mohrbeck.

Paratype: One juvenile, 3.4 mm, ZMH K-60663 , DSB_3681, St. Ma 16–28, 11°49.654’ N, 117°00.299’ W- 11°49.902’ N, 116°59.174’ W; 4143 – 4133 m, 1 May 2016, leg. Annika Janssen.

Additional material: One individual sex undetermined, broken in two parts, DNA extracted from anterior part, posterior part preserved but not used for taxonomic evaluation, ZMH K-60664, DSB_3683, St. Ma 16–95, 11°47.862’ N, 117°30.639’ W- 11°47.152’ N, 117°29.490’ W, 4356–4359 m, 9 May 2016, leg. Annika Janssen.

The registered type material is deposited in the Zoological Museum of Hamburg, Germany.

Type locality: Eastern central Pacific, CCZ, St. Ma 16–25, 11°49.143’ N, 116°58.492’ W- 11°49.975’ N, 116°57.797’ W; 4107– 4101 m.

Etymology: The species is named for Dr. Teresa Jażdżewska, the first author’s mother and a specialist in ephemeropteran and hirudinean taxonomy, diversity and ecology.

Description: Based on male, 5.5 mm, St. Ma 16–25. Head ( Fig. 7 ): longer than deep, longer than pereonites 1–2 combined; no eyes or ocular pigment visible; rostrum curved but not deflexed, the angle between head dorsal margin and rostrum margin more than 90 °, rostrum reaching 2/3 of first article of peduncle of antenna 1; interantennal lobe moderate, subtriangular. Antenna 1 ( Fig. 8 ): subequal in length to antenna 2; length ratios of peduncle articles 1–3 1:0.7:0.4; flagellum 12-articulate, first article longer than article 3 of peduncle; accessory flagellum 1-articulate, minute, slender, length 0.1 × first flagellum article; peduncle sparsely setose, flagellum naked. Antenna 2 ( Fig. 8 ): peduncle moderately setose; length of article 4 0.9 × article 5; flagellum broken at sixth article (right antenna 2–7-articulate). Upper lip (labrum) ( Fig. 8 ): damaged during preparation. Mandible ( Fig. 8 ): incisor margins with five (left) or six (right) teeth; left lacinia mobilis six-cusped; right lacinia mobilis narrower with four cusps; accessory spine rows with four slender, pectinate spines; molar columnar, strongly triturative, denticulate, with one associated seta; palp 3-articulate, article 1 short, article 2 length 0.7 × article 3, with seven posterodistal setae, article 3 slightly tapering distally, anterior margin with three (left) or four (right) setae, posterior margin with 11 setae, apically with two or three setae. Lower lip ( Fig. 8 ): outer lobes broadly rounded, mandibular lobes narrow; inner lobes large, separate. Maxilla 1 ( Fig. 8 ): inner plate oval, with two distal setae; outer plate with eight acute setal-teeth (three/four with bifurcate tips); palp 2-articulate, longer than outer plate, robust, rounded apically, article 1 short, length 0.25 × article 2, article 2 with eight apical/subapical setae and one long, lateral setae. Maxilla 2 ( Fig. 8 ): inner plate wider than outer, right inner plate also shorter than outer (left subequal in length), inner plate with setae and spines apically and subapically, fine setules along inner and outer margins; outer plate rounded with apical spines and setae, with one moderately long apicolateral setae. Maxilliped ( Fig. 9 ): inner plate subrectangular, reaching about 0.3 × basal article of palp, apical margin with seven slender spines; outer plate slender and slightly curved, long, reaching 0.5 × length of palp article 2, apical and medial margins with setae and small spines; palp 4-articulate, strong; article 1 tapering distally; article 2 triangular, widest at the midpoint, with strong medial setae; article 3 expanded mediodistally, not produced along article 4; article 4 strong, slightly curved; length ratios of articles 1–4 1:1.8:0.7:1.

Pereon. Pereonite 1 ( Fig. 7 ) longer than pereonite 2, pereonites 3–6 of similar length, longer than 2, pereonite 7 the longest, extending dorsally into a sharp posteriorly directed tooth. Gnathopod 1 ( Fig. 9 ): coxa subtriangular, anterodistal corner subacute, posterodistal corner rectangular, ventral margin with single short seta anteriorly placed, width to depth ratio 1:1; basis straight, slightly expanded distally, distal half of anterior margin with row of long setae, posterior margin with long setae (some delicately plumose), posterodistal corner with single spine, some short setae on the inner surface; merus, posterodistal lobe rounded, moderately setose; carpus strongly expanded, anterior margin with six setae along distal half (some delicately plumose), posterior lobe rounded with setae along posterior and distal margins; propodus subchelate, triangular, strongly widening distally, anterior margin moderately setose, palm almost as long as hind margin, transverse, convex, margin crenate, with fine denticulations, with medial spines and lateral row of submarginal setules, palmar corner subrectangular with one spine; dactylus curved, distinctly longer than palm. Gnathopod 2 ( Fig. 10 ): coxa narrow, slightly tapering distally, width 0.5 × depth, apex rounded, ventral margin naked; basis straight, c. 15 long setae forming circular patch anterodistally, four long setae at posterior margin, three setae at posterodistal corner, some setae at the surface; merus, posterodistal lobe narrow, subacute, moderately setose; carpus strongly expanded, wider than propodus, anterior margin with two setae, posterodistal lobe subacute, extending palmar corner of propodus, distal margin oblique armed with a row of spines, posterior margin with moderately long setae; propodus longer than carpus, subchelate, triangular, strongly widening distally, anterior margin with four long setae regularly placed, group of setae at anterodistal corner, palm shorter than hind margin, transverse, convex, margin crenate, with fine denticulations, with medial spines and lateral row of submarginal setules, palmar corner subrectangular with one spine; dactylus curved, just longer than palm. Pereopod 3 ( Fig. 10 ): coxa subrectangular, wider and deeper than coxa 2, ventral margin naked; basis longer than coxa, narrow, length 5.4 × width, some long setae anteriorly; merus slightly expanded distally, two groups of setae anterodistally and three groups of setae posteriorly; carpus narrow, length 1.1 × merus, one group of setae at anterodistal corner, posteriorly armed with long setae organized in eight groups; propodus length 0.6 × carpus, with a group of setae anterodistally and five groups of moderately long setae along posterior margin; dactylus thin, as long as propodus. Pereopod 4 ( Fig. 10 ): coxa wider than deep, anterior margin strongly convex, extending distally, coxa the widest almost at 2/3 of its depth, ventral margin naked, posteroventral lobe huge, blunt (width to depth ratio of the lobe 1:0.7), posterior margin deeply excavated; basis long and narrow, length 5.4 × width, sparse long setae at anterior and posterior margin as well as on the surface; merus slightly expanded, sparsely setose; carpus-dactylus broken off. Pereopod 5 ( Fig. 11 ): coxa about as deep as coxa 4, bilobed, posterior lobe expanded ventrally, ventral margin straight, with one seta anteriorly placed, anterior lobe 0.5 × depth of posterior lobe; basis narrow, length 2.8 × width, five long, delicately plumose setae at anterior margin, three long setae along posterior margin; merus as long as basis, sparsely setose; carpus-dactylus broken off. Pereopod 6 ( Fig. 11 ): coxa partly damaged; basis narrow, length 3.3 × width, sparsely setose; merus as long as basis, sparsely setose; carpus-dactylus broken off. Pereopod 7 ( Fig. 11 ): coxa wider than deep, rounded posteriorly; basis ovate, length 1.6 × width, widest in the mid length, tapering distally, anterior margin strongly convex, one short spine at anterodistal corner, posterior margin slightly oblique in distal half, denticulate, posterodistal lobe absent; merus distally damaged, with groups of setae both anteriorly and posteriorly (some setae broken); carpus-dactylus broken off.

Pleon. Pleonites 1–3 ( Fig. 7 ) with distinct mid-dorsal, posteriorly directed teeth. Epimera: 1 and 3 evenly rounded, epimeron 2 posterodistal corner subquadrate, epimeron 3 delicately serrate. Pleopods [pleopod 1 ( Fig. 12 )]: powerful, peduncles and rami long.

Urosome. Urosomite 1 ( Fig. 7 ) longest, produced distally into a sharp, large, upright tooth; urosomite 3 longer than 2. Uropods ( Fig. 12 ): Uropod 1 (damaged): peduncle margins with some moderately long setae; rami broken off. Uropod 2 (rami damaged): peduncle with some moderately long setae; inner ramus with sparse setae. Uropod 3: peduncle short, peduncle length 0.3 × inner ramus; inner and outer ramus with short spines along lateral margins. Telson: ( Fig. 12 ) short, length 1.5 × width, cleft 35%, lobes subacute, widely diverging, notched subapically, tips unequal in size (inner slightly shorter than outer; on one side outer tip broken), single seta placed in the notch.

Intraspecific variation: No distinct differences were observed between the holotype and the mature female collected. The difference between adult individuals and the juveniles is expressed by the number of articles of flagella of antenna 1 and antenna 2 which is smaller in the latter.

Molecular identification: Following the definition given by Pleijel et al. (2008), the sequence of the holotype male of O. teresae ( ZMH K-60661, GenBank accession number MW 377944 ) is designed as a hologenophore of all obtained sequences. The sequences of the paratype and additional individuals of the species are deposited in GenBank with the following accession numbers: MW 377925 , MW 377934 , MW 377942 . The species has received also a Barcode Index Number from BOLD: AEB1523 (dx.doi.org/10.5883/ BOLD: AEB1523 ) .

Distribution: Eastern central Pacific, CCZ ( Fig. 25 ), 4101–4359 m.

Figures

Figure 7. Oedicerina teresae sp. nov. Holotype male (ZMH K-60661, DSB_3680). A, habitus. B, head. C, pereonite 7, pleonites and urosomites, the arrow indicates close up of the epimeral plate 3 margin. Scale bar = 0.5 mm.

Figure 8. Oedicerina teresae sp. nov. Holotype male (ZMH K-60661, DSB_3680): lA1, left antenna 1; lA2, left antenna 2; lMx1, left maxilla 1; rMx1, right maxilla 1; lMd, left mandible; rMd, right mandible; UL, upper lip; lMx2, left maxilla 2; rMx2, right maxilla 2; LL, lower lip. Scale bar = 0.1 mm, not all setae and spines shown for clarity.

Figure 9. Oedicerina teresae sp. nov. Holotype male (ZMH K-60661, DSB_3680): Mxp, maxilliped; lG1, left gnathopod 1. Scale bar = 0.1 mm, not all setae shown for clarity.

Figure 10. Oedicerina teresae sp. nov. Holotype male (ZMH K-60661, DSB_3680): lG2, right gnathopod 2; lP3, left pereopod 3; lP4, left pereopod 4. Scale bar = 0.1 mm, not all setae shown for clarity.

Figure 11. Oedicerina teresae sp. nov. Holotype male (ZMH K-60661, DSB_3680): lP5–7, left pereopod 5–7, respectively. Scale bar = 0.1 mm, not all setae shown for clarity. The dashed line (long dashes) indicates the place where the appendage was damaged.

Figure 12. Oedicerina teresae sp. nov. Holotype male (ZMH K-60661, DSB_3680): rpl1, right pleopod 1; lU1–U3, left uropod 1–3, respectively; T, telson. Scale bar = 0.1 mm.The zig-zag line indicates the place where the appendage was damaged.

Figure 25. Geographic distribution of the Oedicerina species. A, world distribution of all known species. B, the CCZ with the sampling stations shown where O. henrici sp. nov. and O. teresae sp. nov. were collected. C, KKT area with the sampling stations shown where O. lesci sp. nov. and O. claudei sp. nov. were collected. Station codes as in Table 1.