Cyclocaris lowryi, Horton & Thurston, 2014

Horton, Tammy & Thurston, Michael H., 2014, A revision of the bathyal and abyssal necrophage genus Cyclocaris Stebbing, 1888 (Crustacea: Amphipoda: Cyclocaridae) with the addition of two new species from the Atlantic Ocean, Zootaxa 3796 (3), pp. 507-527 : 511-518

Cyclocaris lowryi sp. nov.

( Figures 4–7 )

Cyclocaris sp. ? nov. Thurston, 1990: 262–265 (ecology).

Cyclocaris sp. nov. Duffy, Horton & Thurston, 2012: 4865 (ecology)

Type material. Holotype: preparatory female, 17.1 mm, carcass and 6 slides; Sta. 12600#44, DEMAR, 9-10 October 1993 (bottom time 10 hours 45 minutes), 21º 05.2’N 31º 06.6’W, 4540 m, Cape Verde Abyssal Plain ; NHMUK 2014 . 437 . Allotype: adult male, 12.6 mm; Sta. 12600#46, DEMAR, 10–11 October 1993 (bottom time 22 hrs 57 mins), 21º 01.2’N 31º 13.0’W, 4555 m, Cape Verde Abyssal Plain ; NHMUK 2014 . 438 . Paratypes: Sta.12600#44, same data as holotype; 124 specimens, NHMUK 2014 . 439–448. Sta. 12600#46, same data as allotype; 263 specimens, NHMUK 2014 . 449–458.

Additional material examined. Specimens retained in the Discovery Collections, National Oceanography Centre, Southampton.

8524#1, BN 1.5/5C, 28 June 1974, 20º 45.5’N 22º 42.5’W –20º 46.6’N 22º 44.3’W, 4412 m, Cape Verde Abyssal Plain , 1 specimen .

9541#18, RMT 8, 18 April 1977, 20º 18.5’N 21º 41.2’W –20º 20.8’N 21º 53.0’W, 3970–4020 m (0–20 metres above bottom), Cape Verde Abyssal Plain , 1 specimen .

9541#19, RMT 8, 18 April 1977, 20º 19.7’N 21º 51.3’W –20º 18.4’N 21º 40.5’W, 3970–4040 m (0–20 mab), Cape Verde Abyssal Plain , 1 specimen .

9629#1, TRAP B, 27–28 October 1977 (bottom time 26 hrs 12 mins), 35º 47.4’N 13º 12.5’W, 4850 m, Horseshoe Abyssal Plain, 2 specimens .

52216#5, AMPHT, 23–25 June 1985 (bottom time 35 hrs 05 mins), 48º 50.02’N 16º 30.42’W, 4842 m, Porcupine Abyssal Plain, 2 specimens .

11261#56, RMT 8M/3, 4 July 1985, 31º 14.7’N 25º 14.6’W – 31º 17.6’N 25º 18.3’W, 5415–5425 m (25–11 mab), Madeira Abyssal Plain, 1 specimen.

11261#64, RMT 1M/2, 6 July 1985, 31º 19.2’N 25º 21.4’W – 31º 24.3’N 25º 21.3’W, 5385–5410 m (48–25 mab), Madeira Abyssal Plain, 1 specimen.

11262#17, BN1.5/3M SBN, 17 July 1985, 31º 13.3’N 25º 14.4’W – 31º 11.5’N 25º 09.6’W, 5432 m, Madeira Abyssal Plain, 1 specimen.

11262#19, BN1.5/3M SBN, 18 July 1985, 31º 19.8’N 25º 29.0’W – 31º 34.0’N 25º 26.9’W, 5432 m, Madeira Abyssal Plain, 5 specimens.

12174#20, BSNACK, 18–23 August 1990 (bottom time 111 hrs 34 mins), 31º 07.6N 21º 10.0’W, 4941 m, Madeira Abyssal Plain, 9 specimens.

52701#35, DEMAR, 22–23 May 1991 (bottom time 20 hrs 21 mins), 48º 48.5’N 16º 23.6’W, 4843 m, Porcupine Abyssal Plain, 1 specimen .

12600#14, BSNACK, 1–7 October 1993 (bottom time 138 hrs 50 mins), 21º 01.1’N 31º 10.8’W, 4549 m, Cape Verde Abyssal Plain , many specimens .

12600#41; BSNACK, 9–14 October 1993 (bottom time 130 hrs 4 mins), 21º 04.6’N 31º 11.6’W, 4615 m, Cape Verde Abyssal Plain , 19 specimens .

12600#60; DEMAR, 14–16 October 1993 (bottom time about 40 hours, soluble link parted prior to proposed release), 21º 05.1’N 31º 12.9’W, 4569 m, Cape Verde Abyssal Plain , many specimens .

13077#4, NIOZ LANDER, 14–18 March 1997 (bottom time 79 hrs 44 mins), 48º 55.82’N 16º 35.25’W, 4844 m, Porcupine Abyssal Plain, 2 specimens .

13077#35, NIOZ LANDER, 19–23 March 1997 (bottom time 82 hrs), 48º 58.10’N 16º 24.93’W, 4845 m, Porcupine Abyssal Plain, 2 specimens .

15734#1, DEMAR, 1–2 August 2005, (bottom time 21 hrs 28 mins), 39º 29.78’N 09º 57.89’W, 3600 m, Nazaré Canyon, 1 specimen .

15741#1, DEMAR, 4–5 August 2005 (bottom time 24 hrs 22 mins), 39º 34.95’N 10º 16.5’W, 4286 m, Nazaré Canyon, 25 specimens .

56839#1, VET, 4–5 May 2006 (bottom time 24 hrs 12 mins), 38º 06.57’N 09º 58.18’W, 4445 m, Setúbal Canyon, 1 female specimen.

56847#1, DEMAR, 7–8 May 2006 (bottom time 24 hrs 34 mins), 39º 35.50’N 10º 19.00’W, 4403 m, Nazaré Canyon, 3 specimens .

Etymology. This species is named for Jim Lowry in recognition of his huge contribution to our knowledge of amphipods in general and lysianassoids in particular.

Description. Holotype female, 17.1 mm. Head: exposed, deeper than long, rather short dorsally but telescoped into peraeonite 1; lateral cephalic lobe moderate, rounded; rostrum very small. Eyes: four, pigmented, lacking ommatidea, pigment lost in alcohol; upper, small, sub-oval; lower, larger, sub-oval, in cephalic lobe. Antenna 1: short, 0.15 x body; peduncular article 1 short; peduncular article 2 short, 0.3 x article 1; peduncular article 3 short, 0.3 x article 1; primary flagellum 10-articulate; accessory flagellum long, 0.6 x primary flagellum, five-articulate, article 1 as long as articles 2–5 combined; callynophore strong two-field; calceoli absent. Antenna 2: short, 1.65 x antenna 1; peduncle with brush setae, not geniculate; peduncle article 1 not greatly enlarged; peduncle article 3 short, 0.4 x article 4; articles 4 and 5 not enlarged; flagellum well developed, 20-articulate.

Mouthpart bundle: subquadrate. Epistome and upper lip: separate, rounded, weakly produced, epistome weakly dominant. Mandible: incisor smooth, weakly convex, with minute ventral hook; lacinia mobilis present on left mandible only, a slender peg minutely bifurcate distally; accessory setal rows with seven simple robust setae and many setules; molar a setose, proximally directed, non-triturating flap; palp attached distally; article 1 short, broader than long; article 2 slender, length 4.0 x breadth, with about 20 A2 setae on distal 0.4; article 3 slender, tapering, length 4.2 x breadth, with 25 D3 setae and three E3 setae. Lower lip: outer plates gaping, setose marginally, inner plates apparently absent (but see below), molar processes prominent, rounded distally. Maxilla 1: inner plate slender, with nine pappose setae along inner margin; outer plate with 11 setal-teeth in a 7/4 crown arrangement, ST1–5 weakly one-, two- or three-cuspidate, ST 6–7 simple, ST7 displaced from ST6, STA–C obscurely cuspidate, STD simple; palp large, two-articulate, article 1 short, article 2 broadened with three short robust setae on tridentate apical margin, one flag seta, two subapical robust setae, and one pappose seta on dorsal margin. Maxilla 2: inner plate short, 0.67 x length of outer plate, tapering, with rows of marginal and submarginal pappose and simple setae; outer plate with marginal and apical stout and slender setae. Maxilliped: inner plate large, subtriangular, with three very small nodular spines on strongly oblique apical margin, oblique setal row strong, with ten pappose setae; outer plate large, subovate, with 19 pappose setae apically and laterally, no robust setae, and about 20 minute nodular setae on medial margin; palp large, four-articulate, article 2 slender, length 2.7 x breadth, article 3 long, slender, length 2.7 x width, dactyl well-developed, slender, with three short subterminal setae and two rows of minute denticles on the medial surface.

Gnathopod 1: simple; coxa vestigial, anterior margin straight, posterior margin convex; basis long, slender, length 5.8 x breadth, anterior margin straight, lacking setae, posterior margin straight, with one short seta; ischium long, length 3.7 x breadth; carpus very long, subquadrate, lacking posterior lobe, margins subparallel, length 4.1 x. breadth, 1.3 x length of propodus; propodus long, subquadrate, length 4.8 x breadth, margins weakly convergent, anterior weakly convex, posterior weakly concave, palm absent; dactylus simple, length 0.29 x propodus, with subterminal setae. Gnathopod 2: subchelate; coxa vestigial, subrectangular; basis long, slender, curved, anterior margin convex, length 6.1 x breadth; ischium long, length 3.3 x breadth; carpus very long, length 5.7 x breadth, margins subparallel, posterior margin straight, 2.3 x length of propodus; propodus subovate, length 3.0 x breadth, setulose, palm slightly acute, weakly convex, serrate distally; dactylus inserted near middle of propodus distal margin, reaching corner of palm. Peraeopod 3: coxa large, weakly expanded, broadly rounded distally; basis straight, margins subparallel; merus narrowly produced anterodistally, extending 0.37 x length of carpus; dactyl slender, curved, 0.43 x length of propodus. Peraeopod 4: coxa as deep as wide, posteroventral lobe short, broadly rounded; distal articles as in peraeopod 3. Peraeopods 5–7: subequal in length. Peraeopod 5: coxa unequally bilobate, posterior lobe deeper, strongly produced posteriorly; basis expanded, subovate, posterior margin convex, posterodistal margin broadly rounded; merus slender, produced posterodistally, extending 0.23 x length of carpus, propodus slender, length 6.8 x breadth; dactylus slender, curved, 0.33 x length of propodus. Peraeopod 6: coxa bilobate, posterior lobe deeper, expanded posteriorly; basis expanded, posterior margin convex, posterodistal lobe broadly rounded; merus slender, posterior margin weakly convex, weakly produced. Peraeopod 7: coxa posterior lobate; basis expanded, tapering distally, posterior margin weakly convex, posterodistal lobe narrowly rounded; merus slender, weakly produced posterodistally. Gills: gnathopod 2 to peraeopod 7; peraeopod 7 gill large. Oostegites: gnathopod 2 to peraeopod 5.

Pleonites 1 to 3: not carinate. Epimeron 1: broadly rounded ventrally. Epimeron 2: subrectangular; anteroventral corner rounded, posteroventral corner with acute tooth, posterior margin sinuous, ventral margin setose. Epimeron 3: expanded distally; anteroventral corner rounded, posteroventral corner with subacute tooth, posterior margin concave, ventral margin setose. Urosome: urosomite 1 with low rounded boss; urosomite 2 nearly occluded dorsally; urosomite 3 produced posterolaterally, markedly concave dorsally, with strong dorsolateral flanges. Uropod 1: peduncle with 12 dorsolateral robust setae and nine dorsomedial robust setae; inner ramus 0.57 x length of peduncle, with three dorsomedial setae; outer ramus 0.90 x inner ramus, with three dorsolateral setae. Uropod 2: peduncle with four dorsolateral robust setae and two dorsomedial robust setae; inner ramus 1.1 x length of peduncle, with two lateral and five medial setae; outer ramus 0.72 x inner ramus, with four lateral and four medial setae. Uropod 3: peduncle short, with four dorsomedial setae; rami subequal, lanceolate, with plumose setae on medial margins; inner ramus 1.6 x peduncle, with five lateral and two medial robust setae; outer ramus 2- articulate, article 2 length 0.31 x article 1, article 1 with four lateral and one medial robust setae. Telson: long, lobes tapering, length 1.8 x breadth, cleft 81%; lobes with four dorsolateral robust setae, apices notched with one robust seta.

Male. Similar to female except for calceoli on both antennae and a longer callynophore.

Remarks. C. lowryi differs from C. tahitensis and C. guilelmi by the rounded triangular eyelobe. For characters separating C. lowryi from C. franki , see under the latter species.

The lower lip as figured here agrees closely with the illustration of Chevreux (1935) and appears to lack inner lobes. However, the lower lip of the holotype was damaged during dissection. An examination of other specimens shows that inner lobes are present but are very small; much smaller than those shown for C. guilelmi by Barnard (1959). They project dorsally, i.e. perpendicular to the outer lobes, and are fused with separated, rounded apices.

Most material has come from baited traps set at abyssal depths, but individuals occupy the benthopelagic zone (present material; Thurston, 1990).

Distribution. Atlantic Ocean, 8–49˚N. Guiana, Cape Verde, Madeira, Horseshoe, Iberian and Porcupine Abyssal Plains, Portuguese canyons, 3600–5432 m, benthic and abyssopelagic (present material; Thurston, 1990).

Figures

FIGURE 4. C. lowryi sp. nov.: holotype; adult female, 17.1 mm, habitus.

FIGURE 5. C. lowryi sp. nov.: holotype; adult female, 17.1 mm, mouthparts.

FIGURE 6. C. lowryi sp. nov.: holotype; adult female, 17.1 mm, gnathopods, peraeopods and telson.

FIGURE 7. C. lowryi sp. nov.: holotype; adult female, 17.1 mm, head, epimera and uropods. Allotype; adult male, 12.6mm, head.