Meterythrops pictus Holt and W. Tattersall, 1905

Fukuoka, Kouki & Murano, Masaaki, 2006, Taxonomy of the genus Meterythrops (Crustacea: Mysida: Mysidae), with a redescription of M. microphthalmus and descriptions of two new species, Journal of Natural History 40 (27 - 28), pp. 1641-1674 : 1651-1655

Meterythrops pictus Holt and W. Tattersall, 1905

( Figures 4 , 12D ) Meterythrops picta Holt and W. Tattersall 1905, p 116 –117, 143, Plate 19, Figures 5–7 ,

Plate 25, Figures 8 , 9 ; 1906, p 23–24; Hansen 1908, p 107; Zimmer 1909, p 87–88,

Figures 173, 174; W. Tattersall 1911, p 28–29; Stephensen 1912, p 79–80; Illig 1930, p 428; Stephensen 1933, p 12; W. Tattersall 1951, p 113; W. Tattersall and O. Tattersall 1951, p 209–212, Figures 45B–F, 46; O. Tattersall 1955, p 117–118; Birstein and Tchindonova 1962, p 65–66; Ii 1964, p 314–319, Figures 81, 82; Murano 1970b, p 138– 139; 1971, p 47 (list); 1977, p 167–169, Figure 17; Müller 1993, p 123–124 (list).

Meterythrops indica Hansen 1910, p 63 –64; Illig 1930, p 428; W. Tattersall 1939, p 235; Pillai 1965, p 1706.

Meterythrops affin. picta: Zimmer 1914, p 388 .

Meterythrops affinis Coifmann 1936a, p 84 ; 1936b, p 36–38, Figure 24.

Material examined

Type material. BM (NH) 1905.6.6.4-5, type, one immature male (13 mm, damaged), off Achill , Ireland, about 700 m, tow-net on trawl-head, 24 August 1901 .

Material reported by Murano (1977). See Table II. On data, see Murano (1977). Other Japanese material. NSMT-Cr 16747, one female (9.5 mm), Sagami Bay (35 ° 06.19N, 139 ° 20.49E), central Japan, 0–470 m, oblique tow, ORI net, 24 January 1964, R / V Tansei- Maru cruise, coll. M. Murano. NSMT-Cr 16748, one female (damaged), Stn 193, north of Amami-oshima Island (29 ° 08.09N, 129 ° 39.19E), Amami Islands , southern Japan, 0– 1000 m, oblique tow, ORI net, 25 April 1970, R / V Tansei-Maru cruise, coll. M. Murano. NSMT-Cr 16749, one immature male (8.5 mm), one immature female (damaged), and two juveniles (5.1 and 7.2 mm), Stn H 154-3, west of Okinawa Island (26 ° 13.59N, 125 ° 13.09E), southern Japan, 0–900 m, oblique tow, ORI net, 12 May 1971, R / V Hakuho- Maru cruise, coll. M. Murano. NSMT-Cr 16750, one male (12.1 mm), Stn 222-6, west of Okinawa Island (26 ° 08.29N, 125 ° 12.09E), southern Japan, 0–1500 m, oblique tow, ORI net, 9 August 1974, R / V Hakuho-Maru cruise, coll. M. Murano. NSMT-Cr 16751, one immature male (5.2 mm) and 41 juveniles (2.7–4.9 mm), Tateyama Bay , Chiba, central Japan, 390 m, sledge net, 21 April 1990, TR/ V Seiyo-Maru cruise. NSMT-Cr 16752, one immature male (5.6 mm) and three juveniles (2.7 mm and damaged), Tateyama Bay , Chiba, central Japan, 490 m, sledge net, 21 April 1990, TR/ V Seiyo-Maru cruise .

Indonesian material. NSMT-Cr 16753, two immature females (damaged), Timor Sea (09 ° 27.09S, 127 ° 58.69E), 610–690 m, plankton net installed at mouth of beam trawl, 18– 19 June 1972, R / V Hakuho-Maru cruise, coll. M. Murano. NSMT-Cr 16754, one immature male (damaged), Sahul Shelf (12 ° 42.29S, 123 ° 07.69E), Timor Sea, 535–547 m, plankton net installed at mouth of beam trawl, 26 June 1972, R / V Hakuho-Maru cruise, coll. M. Murano.

British material. Two males (damaged), two immature males (8.6 and 9.0 mm), three females (11.2 mm), and nine immature females (7.3–10.5 mm), Rockall Trough, western Ireland, date unknown, on loan from J. Mauchline.

Supplemental description

Penis 2.5 times as long as broad in lateral view, armed with about 15 short plumose setae on posterior margin and three short, naked setae near apex of posterolateral part; apex rounded armed with three long, mesially curved setae and a short seta ( Figure 4A ).

Female with tuft of setae on sixth thoracopod and with developed oostegites on seventh and eighth thoracopods; oostegite on seventh thoracopod with baling lobe.

Fourth pleopodal endopod of male six-segmented; third, fourth, and fifth segments armed with modified seta at mesial distal angle, these setae extending beyond tip of terminal setae on ultimate segment, slightly thicker than others and furnished with fine setae on distal one-fourth ( Figure 4 B–D). Fourth pleopodal exopod of male six-segmented, as long as endopod, without modified setae ( Figure 4B ).

Fifth pleopodal endopod of male six-segmented, without modified setae ( Figure 4E ). Fifth pleopodal exopod of male six-segmented, as long as endopod; fourth and fifth segments armed with modified seta at mesial distal corner, these modified setae with same setulation as those of endopod of fourth pleopod ( Figure 4E ).

Distribution

This species is widely distributed in the meso- and bathypelagic zones deeper than 500 m of the Atlantic, Indian, and West Pacific Oceans: Ireland ( Holt and Tattersall 1905, 1906; Tattersall 1911), Iceland ( Hansen 1908), the Denmark Strait ( Stephensen 1912, 1933), Great Britain ( Tattersall and Tattersall 1951), South Africa ( Zimmer 1914; Illig 1930; Tattersall 1955), Sri Lanka ( Illig 1930), the Gulf of Aden ( Coifmann 1936b), northeastern USA ( Tattersall 1951), Somalia ( Birstein and Tchindonova 1962), Indonesia ( Pillai 1965; present study), the Arabian Sea ( Pillai 1965), and Japan ( Ii 1964; Murano 1977; present study).

This species was collected by trawl ( Holt and Tattersall 1905; Tattersall 1911; Stepehnsen 1933, present study), a net towed vertically or obliquely ( Hansen 1910; Illig 1930; Birstein and Tchindonova 1962; Ii 1964; Murano 1977; present study), and a bottom net ( Murano 1977).

Remarks

The presence of modified setae on the male pleopods and the components of the marsupium are reported for the first time.

Figures

Figure 4. Meterythrops pictus (Holt and W. Tattersall, 1905). Male (10.5 mm) from western Ireland. (A) Left penis, lateral; (B) left fourth pleopod, posterior; (C) modified seta of fourth pleopod; (D) normal plumose seta of fourth pleopod; (E) left fifth pleopod, posterior. Arrows show the modified seta.

Figure 5. Meterythrops robustus Smith, 1879. Male (14.2 mm, NSMT-Cr 16756) from off Onagawa. (A) Anterior end of body, dorsal; (B) right antenna, dorsal; (C) left mandible; (D) left maxillule, posterior; (E) left maxilla, posterior; (F) right penis, lateral.

Figure 6. Meterythrops robustus Smith, 1879. (A–G) Male (14.2 mm, NSMT-Cr 16756) from off Onagawa; (H, I) female (12.6 mm, NSMT-Cr 16755) from off Onagawa. (A–E) Left first to fifth pleopods, anterior; (F) uropod, ventral; (G) spiniation on anterior part of uropodal endopod, ventral; (H) uropod and telson, dorsal; (I) apical part of telson, dorsal.

Figure 7. Meterythrops sp. Murano, 1977. Female (ca 25 mm, NSMT-Cr 16813). (A) Sternal process on first to third and fifth to eighth thoracic somites, ventral; (B) right mandible; (C) right maxillule, ventral; (D) right maxilla, ventral; (E) endopod of right first thoracopod; (F) endopod of right second thoracopod; (G) right third thoracopod; (H) endopod of right eighth thoracopod; (I) uropod, ventral; (J) spiniation on statocyst region of uropodal endopod, ventral; (K) uropod and telson, dorsal.

Figure 8. Meterythrops intermedius sp. nov. (A, C–H) Male (18.3 mm, holotype, NSMT-Cr 16758); (B) female (13.3 mm, paratype, NSMT-Cr 16759). (A, B) Anterior end of body, dorsal; (C) left antenna, ventral; (D) left mandible; (E) left maxillule, posterior; (F) left maxilla, posterior; (G) left first thoracopod; (H) left second thoracopod.

Figure 9. Meterythrops intermedius sp. nov. (A, G–I) Female (13.3 mm, paratype, NSMT-Cr 16759); (B–F, J, K) male (18.3 mm, holotype, NSMT-Cr 16758). (A) Left third thoracopod; (B) right penis, lateral; (C) left first pleopod, posterior; (D) left fourth pleopod, posterior; (E) left fifth pleopod, posterior; (F) distal part of terminal setae of endopod of right fifth pleopod, posterior; (G) left first pleopod, anterior; (H) left fourth pleopod, anterior; (I) left fifth pleopod, anterior; (J) uropod and telson, dorsal; (K) endopod of uropod, ventral.

Figure 12. (A) Meterythrops japonicus, from Ogasawara, Japan; (B) M. microphthalmus, from Alaska; (C) M. microphthalmus, from the Japan Sea; (D) M. pictus, from Scotland; (E) M. robustus, type, from Massachusetts Bay, USA; (F) M. robustus, from Onagawa, Japan; (G) M. intermedius, from Alaska; (H) M. tenusipinis, from Enshunada, Japan.