Iphinoe sagamiensis Gamô, 1958

Iphinoe sagamiensis Gamô, 1958 View in CoL

( Fig. 1 View FIGURE 1 )

Gamô (1958): 23–24, fig. 1; Gamô (1962): 22–24, fig. 9.

Diagnosis. Ovigerous female. Carapace 0.23–0.26 times total body length, 2.1–2.5 times as long as wide, 2.1–2.7 times depth; median dorsal ridge with 8–16 teeth; width of round eye lobe 0.15–0.20 times carapace width, 0.9–1.2 times eye lobe length; antero-lateral angle with 3–6 teeth; inferior margin without teeth. Antenna 1 peduncle article 1 0.90–1.10 times as long as article 3. Pereopod 1 propodus with long seta on inner distal corner; dactylus 0.78–0.89 times as long as carpus. Uropod peduncle with spiniform setae. Adult male. Median dorsal ridge of carapace very weak or obsolete, with 1–2 prominent spines; eye lobe 0.20–0.28 times as carapace width, 1.1–1.4 times as long as eye lobe length; antero-lateral angle with 3–6 teeth; inferior margin without teeth. Antenna 1 main flagellum article 1 with 2–4 aesthetascs.

Material examined. Five ovigerous females, 6.6–7.6 mm, dissected, 5 adult males, 6.0–7.0 mm, 3 specimens dissected ( NSMT Cr-32961), Omaezaki, southern coast of Honshu , 34°38.26'N, 138°17.86'E – 34°38.12'N, 138°17.86'E, 70.5–71 m (KT-10-16, St. OM), 13 August 2010 GoogleMaps ; 4 ovigerous females, 4.9–6.1mm, 1 adult male, 5.2 mm, partially dissected, Shimoda, Sagami Bay , 34°39.16'N, 138°57.04'E – 34°38.98'N, 138°56.81'E, 42–47 m, 25 October 2017 GoogleMaps ; 3 preparatory females, 5.8–6.3 mm, partially dissected, off Shimoda , 34°41'N, 138°57'E, 14 m, 27 November 2014 GoogleMaps ; 2 ovigerous females, 7.0, 7.2 mm, 3 preparatory female, 6.7–7.7 mm, partially dissected, Misaki, Sagami Bay 35°09.44'N, 139°36.85'E, 4 m, 19 January 2015 GoogleMaps ; 1 ovigerous female, 8.3 mm, 3 adult males, 7.3–8.0 mm, partially dissected, Misaki, Sagami Bay , 35°09.55'N, 139°36.98'E, 4–4.5 m, 13 March 2013 GoogleMaps ; 1 ovigerous female, 6.7 mm, partially dissected, Misaki, Sagami Bay , 35°09.55'N, 139°36.94'E, 4.5 m, 24 January 2014 GoogleMaps ; 1 ovigerous female, 8.2 mm, partially dissected, Enshu-nada, southern coast of Honshu , 34°37.52'N, 137°59.38'E – 34°37.46'N, 137°59.53'E, 52–62 m (KT-02-5, St. EN 4-1), 27 May 2002 GoogleMaps ; 1 ovigerous female, 8.3 mm, 2 preparatory females, 9.3, 10.0 mm, partially dissected Enshu-nada , 34°34.78'N, 138°04.89'E – 34°34.63'N, 138°04.82'E, 69– 74 m (KT-02-5, St. EN 2-2), 26 May 2002 GoogleMaps ; 3 ovigerous females, 6.1–7.5 mm, 1 preparatory female (damaged), partially dissected, Enshu-nada , 34°34.79'N, 138°04.0' E – 34°34.76'N, 138°03.88'E, 84–88 m (KT-10-16, St. EN- 1), 13 August 2010 GoogleMaps ; 1 subadult male, 7.1 mm, partially dissected, Cape Toi, eastern coast of Kyushu , 31°20.05'N, 131°17.46'E – 31°20.07'N, 131°16.88'E, 101 m (TY02), 22 May 2002, collected by M. Shimomura. GoogleMaps

Description of selected characters. Ovigerous females, 4.9–8.3 mm. Carapace 0.24–0.26 times total body length, 2.14–2.55 times width, 2.09–2.70 times depth; median dorsal ridge with 8–16 teeth; pseudorostral lobes 0.11–0.16 times carapace length, not in contact at anterior end ( Fig. 1B View FIGURE 1 ); width of eye lobe ( Fig. 1B View FIGURE 1 ) 0.15–0.20 times carapace width, 0.93–1.17 times eye lobe length; antennal notch deep; antero-lateral angle ( Fig. 1A View FIGURE 1 ) rather pointed, succeeded by 3–6 teeth; inferior margin smooth. Pereon 0.96–1.20 times as long as carapace. Pleon 0.48–0.50 times total animal length.

Antenna 1 ( Fig. 1C View FIGURE 1 ) peduncle article 1 1.1–1.5 times as long as article 2, 0.9–1.1 times as long as article 3; article 3 1.1–1.4 times as long as article 2; main flagellum biarticulate, 0.24–0.34 times as long as peduncle article 3, accessory flagellum uniarticulate, 0.4–0.7 times as long as main flagellum article 1.

Antenna 2 with 2–3 plumose setae.

Maxilliped 2 coxa ( Fig. 1D View FIGURE 1 ) rudimentary oostegite strongly bent, with 7–13 setae.

Pereopod 1 ( Fig. 1E View FIGURE 1 ) basis 0.7–0.9 times as long as distal articles together, with one spine on distal end of ventral surface; carpus 1.2–1.4 times as long as merus, 0.7–0.9 times as long as propodus; propodus 1.3–1.6 times as long as dactylus, with long simple seta on inner distal corner (arrowed on figure); dactylus 0.8–0.9 times as long as carpus.

Uropod peduncle with 11–12 spiniform setae on inner margin.

Adult males, 5.2–8.0 mm. Carapace ( Fig. 1F, G View FIGURE 1 ) 0.24–0.27 times total body length, 2.63–2.98 times as long as wide, 2.29–2.45 times depth; median dorsal surface nearly straight, seen from side; weak median dorsal ridge on frontal lobe, with 1–2 prominent spines, without minute spines; pseudorostrum 0.11–0.16 times carapace length; left and right pseudorostral lobes not in contact at anterior end ( Fig. 1G View FIGURE 1 ); width of round eye lobe ( Fig. 1G View FIGURE 1 ) 0.22–0.28 times carapace width and 1.1–1.4 times eye lobe length; antennal notch triangular; anterolateral angle not pointed, succeeded by 3–6 teeth; lower margin smooth.

Antenna 1 ( Fig. 1H View FIGURE 1 ) peduncle article 1 1.3–1.5 times as long as article 2 and 1.0–1.2 times as long as article 3; article 3 1.2–1.4 times as long as article 2; main flagellum biarticulate, 0.3–0.5 times as long as peduncle article 3; article 1 with 2–4 aesthetascs; accessory flagellum uniarticulate, 0.4–0.6 times as long as main flagellum article 1.

Pereopod 3 ( Fig. 1I View FIGURE 1 ) basis 1.0–1.2 times as long as distal articles together, globular protrusion near basal end of basis with 4–5 pappose setae.

Remarks. Iphinoe sagamiensis was described from specimens from the southern coast of Honshu (female specimens from Sagami Bay, 20 m ( Gamô 1958), and male specimens from Tanabe Bay, Kii Peninsula ( Gamô 1962). The specimens examined in this study, from the southern coast of Honshu and Kyushu, agree with the description by Gamô.

Iphinoe sagamiensis is similar to Iphinoe tenera Lomakina, 1960 from the Yellow Sea, Bo Hai in the shape of the carapace, but is distinguished from the latter by (1) the anterior portion of carapace in females is without a longitudinal ridge in females, (2) the dorsal surface of the carapace has 1–2 spines and the anterolateral corner has teeth in males, (3) the pereopod 1 propodus has a long seta on inner distal corner, (4) the uropod peduncle is without long setae on the inner margin ( Table 1).

Iphinoe sagamiensis is also similar to Iphinoe gurjanovae from the Yellow Sea but is distinguished from the latter by (1) the median dorsal ridge on the carapace has more teeth, (2) the dorsal surface of carapace has 1–2 spines in males, (3) the uropod peduncle is without long setae ( Table 1).

Distribution. Pacific coast of Honshu (southern area) and Kyushu Islands, Japan, 4– 101 m.