Iphitime doederleini ( Marenzeller, 1902 )

Iphitime doederleini ( Marenzeller, 1902) View in CoL

( Figs 6–8 View Figure 6 View Figure 7 View Figure 8 )

Japanese name : mino-isome.

Iphitime doederleini Marenzeller, 1902, p. 579 –580.

Coelobranchus papillosus Izuka, 1912, p. 135 , pl. 15, figs 1–7.

Materials examined: NSMT-Pol 113618 : fixed and preserved in 10% formalin in seawater, collected in Sagami Bay , Kanagawa, Japan, on 2 December 2021 from Macrocheira kaempferi ( Fig. 4A, B View Figure 4 ) caught with a gill net set at depths of 250–300 m; NSMT-Pol 113619 , fixed and preserved in 70% ethanol, collection date and locality same above, jaws dissected. NSMT-Pol 113620 , fixed and preserved in 70% ethanol, on 22 September 2022, from M. kaempferi collected off Shirahama . Coordination for sampling localities unavailable .

Description

Body flattened, tapered in posterior region; 15–21 mm in length and 1.6 mm in maximum width ( Fig. 6C View Figure 6 ). Prostomium rounded without eyespots ( Fig. 6D View Figure 6 ). Two short digitiform antennae 250 μm in length, dorsally protruding forward on prostomium, without extending beyond prostomium ( Figs 6D View Figure 6 , 7A View Figure 7 , 8A View Figure 8 ). Peristomium represented by two apodous achaetous rings, 1st ring as long as 2nd ring ( Figs 6D View Figure 6 , 7A View Figure 7 ). Chaetae present at first segment after peristomium ( Figs 7A View Figure 7 , 8A View Figure 8 ). Branchiae palmate inserted dorsolaterally, present from chaetiger 1 ( Figs 6D, E View Figure 6 , 7C View Figure 7 , 8A View Figure 8 ). A pair of pygidial cirri digitiform, 320 μm in length ( Fig. 6F View Figure 6 ), slightly longer than antennae ( Fig. 6D View Figure 6 ).

Chaetae comprising of 2–4 supraacicular simple and 7 subacicular compound chaetae ( Figs7C–E View Figure 7 , 8B–D View Figure 8 ). Subacicular compound chaetae with serration ( Figs 7E View Figure 7 , 8D View Figure 8 ).

Jaws of K-type present ( Fig. 6B View Figure 6 ). Sex unknown in the specimen examined.

Rod-like mandibles 240 μm in length, strongly sclerotized, comprising of two shafts distally widening and smooth; distal cutting edge without serration ( Fig. 7B View Figure 7 ). K-type maxillae 340 μm in length, with smooth ice tong-shaped forceps and paired free-denticles ( Fig. 7B View Figure 7 ).

Distribution and habitat: The species is found in the branchial cavity of Macrocheira kaempferi ( Fig. 6A, B View Figure 6 ). Since its first discovery byMarenzeller (1902) in Japanese waters (specific locality not documented), this species has been reported at depths of 548– 640 m in Sagami Bay, under the junior synonym of Coelobranchus papillosus Izuka, 1912 ( Izuka 1912, Imajima and Hartman 1964). It has also been reported from Seto and Minabe, Wakayama, Japan ( Japan Initiative for Biodiversity Information; https://gbif.jp/ gbif_search/dataset? datasetId=snet-1096-105).

Remarks: Specimens collected from Sagami Bay conform to the original description of I. doderleini as well as C. papillosus ( Marenzeller 1902, Izuka 1912).