Carapace smooth between the ridges and large spines. Postrostral carinae with three to five (rarely three) teeth. Chelae of first pereiopods heavily ridged and spinulose, without large spines. No prominent basal spine on outer edge of movable finger of large chela. Inner margin of merus of first pereiopod heavily spinulose. Surface of abdominal tergites conspicuously sculptured, with dorsomedian carina. Fifth abdominal somite without distinct spines on carina separating tergite from pleuron. Dorsomedian carina of sixth abdominal somite without submedian spines. Spine in middle of lateral margin of sixth abdominal somite long, reaching to posterolateral groove of somite.
Type locality Nephrops sagamiensis: "Baia di Sagami" ( = Sagami Bay, Honshu, Japan); two paralectotypes in Museo Civico di Storia Naturale, Milano, Italy, no. 12-13 (ex 1494). Type localities of both Nephrops intermedius and N. sagamiensis: "Misaki und Aburatsubo, Sagamibai, Sammlung Doflein, Nr. 2490"; and of N. sagamiensis (possibly also of N. intermedius): "Station 9, Sagamibai [= 20°10'30"N 139°33'E], 250 m Tiefe, Sammlung Doflein". Through the lectotype selection for both species (see Remarks below), the type locality of both is now restricted to "Aburatsubo, Sagamibai, Japan" [= Aburatsubo near Misaki, Kanagawa Prefecture, Honshu, Japan]; lectotype is the specimen shown on pl.1 fig. 2 of Balss's (1914) paper, it is preserved in ZSM under no. 33/5, the condition of the alcohol specimen is good; one lot of 3 paralectotypes (of both N. intermedius and N. sagamiensis) from "Sagamibai, Misaki, Japan" is also preserved in ZSM, it has no. 33/1, and is preserved in alcohol in a good condition. The lectotypes and paralectotypes of N. intermedius all were collected by F. Doflein in 1904-1905, the lectotype bearing his collecting number 2490. Six lots (10 specimens) of Metanephrops japonicus from Sagami Bay in the collection of ZSM (nos. 33/1, 33/2, 33/3, 33/4, 33/6 and 36/1) are paralectotypes of N. sagamiensis (not quite certain for 33/1 and 33/3) but not of N. intermedius.
Indo-West Pacific region: from east coast of Japan near Sagami Bay to Taiwan.
Habitat and Biology:
Depth range from 300 to 400 m, mostly around 350 m.
Carapace length 3 to 6 cm (males) and 4.5 to 6 cm (females), corresponding to a total body length of 6 to 14 cm (males) and 10 to 14 cm (females).
Interest to Fisheries:
Very little information is available on this species. Baba et al. (1986:280) observed that "in Tosa Bay [Shikoku Island, Japan], the fishing season for M. sagamiensis as well as for M. japonicus, is between September and April, the catch of M. sagamiensis being greater".
Balss (1914: 84, pl. 1 fig. 2), under the name Nephrops japonicus, dealt with several males and females as well as with a juvenile, no exact numbers being given. Later he (Balss, 1921:176) found that this material consisted of two distinct species, and that the specimen figured by him in 1914 was not the true N. japonicus and belonged to a species that he named Nephrops intermedius; again he did not indicate the exact number of specimens of either species before him. Dr. Ludwig Tiefenbacher of the Munich Museum was so kind to inform me that in the collection of his museum there are two lots (4 specimens) labelled N. intermedius and which form part of the Doflein collection; one of these specimens could be identified as the specimen figured by Balss (1914). All four specimens thus are syntypes of N. intermedius and the figured specimen is now selected as the lectotype of that species. In addition the Munich Museum holds five lots of Metanephrops japonicus, all labelled Nephrops japonicus and all from Sagami Bay. Three of those lots (5 specimens) definitely form part of the material dealt with by Balss (1914), as one of them was collected in 1904 by Doflein and two others were collected in 1903 (one by K.A. Haberer, of the other the collector is not indicated but this could well be Haberer also). The two remaining lots only carry the indications "Sagamibai, Japan", but may well have belonged to Balss' (1914) material. Finally there is one lot of Metanephrops japonicus collected in Sagami Bay by Doflein, and thus certainly part of the 1914 material; however, this lot (1 specimen) bears in Balss' handwriting the incorrect label "Nephrops sagamiensis Parisi " ; it is not clear whether or not this is a syntype of Nephrops intermedius, most likely it is not. If it were, however, then the type series of Nephrops intermedius would consist of two species and a lectotype selection is required.
Parisi (1917), when describing his new N. sagamiensis included in it all of Balss' (1914) Nephrops japonicus material; therefore all of Balss' specimens, both those of N. intermedius and those of N. japonicus are syntypes of N. sagamiensis as are also the two specimens before Parisi. The type material of N. sagamiensis thus is definitely heterogeneous and a lectotype should be chosen. The lectotype of N. intermedius is here chosen to be also the lectotype of N. sagamiensis; this action now definitely establishes the identity of the two species, at the same time making their names objectively synonymous.