Meterythrops japonicus Murano, 1977

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 : 1643-1644

Meterythrops japonicus Murano, 1977

( Figures 1 , 12A )

Meterythrops japonica Murano 1977, p 169 –171, Figure 18; Müller 1993, p 123 (list).

Material examined

Holotype: NSMT-Cr 5509, one female (9.5 mm), Tateyama Bay (35 ° 00.29N, 139 ° 48.09E), central Japan, 220–330 m, sledge net, 13 April 1968.

Others. NSMT-Cr 16686, two immature males (5.0 and 5.0 mm), four females (5.0– 6.6 mm), and one immature female (4.4 mm), between Chichi-jima Island and Haha-jima Island (26 ° 59.429N, 142 ° 15.029E), Ogasawara (Bonin) Islands , southern Japan, 357– 543 m, bottom net, 19 June 1995, TR/ V Seiyo-Maru cruise, coll. K. Fukuoka .

Distribution

Meterythrops japonicus had been known only from the type locality, Tateyama Bay , central Japan ( Murano 1977). The present occurrence from adjacent waters of Ogasawara Islands ,

southern Japan, is the second record. The specimens were collected from the near-bottom layer at 220–543 m deep with a sledge net ( Murano 1977; present study).

Remarks

Murano (1977) established this species on the basis of an adult female specimen and assigned it temporarily to Meterythrops because he could not determine whether it belonged to Meterythrops or Parerythrops without a male specimen. The two immature males collected in the present study from adjacent waters of the Ogasawara Islands support the original description by Murano (1977). The exopod of the first pleopod in these immature male specimens, although undeveloped, is divided into multiple segments ( Figure 1A ). Thus, this species likely belongs to Meterythrops , although adult male specimens need to be examined to confirm this classification.

Murano (1977) did not report on the marsupium in the original description. The type specimen and the new specimens from the Ogasawara Islands have a developed oostegite on the seventh and eighth thoracopods, and the oostegite on the seventh thoracopod bears a baling lobe.

Figures

Figure 1. Meterythrops japonicus Murano, 1977. Immature male (5.0 mm, NSMT-Cr 16686) from the Ogasawara Islands. (A) Left first pleopod, posterior; (B) left second pleopod, posterior; (C) uropod and telson, dorsal.

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.