Sampling the depth: New data on the Caecidae (Mollusca, Gastropoda) from northeastern Papua New Guinea Author Walter, Angelo Vannozzi Via M. L. Longo 8, 00151 Rome (Italy) ang.vannozzi@gmail.com Author Renda, Walter Via Bologna 18 / A, 87032 Amantea (CS) (Italy) w.renda1@tin.it text Zoosystema 2024 2024-06-07 46 14 327 347 journal article 299020 10.5252/zoosystema2024v46a14 b5619e29-fcbd-4ddc-9231-138300251568 1638-9387 12548683 23D972D0-F573-429C-816B-F42AFF02D0B1 Caecum japonicum ( Habe, 1978 ) ( Fig. 2 I-L) Pictocaecum japonicum Habe, 1978: 3 , pl. 1, figs 14-17. Caecum japonicum – Vannozzi 2019b: 87 and synonymy therein. TYPE MATERIAL . — Holotype . Japan • sh; Kyushu , Matsugaura , Chiran-cho on the coast of Kagoshima Bay ; NSMT Mo 55371 ( NMNS ). Paratype . Japan • 1 sh; same data as for holotype; NSMT Mo 55372 ( NMNS ) . TYPE LOCALITY . — Pacific Ocean, Japan , Kyushu, Matsugaura, Chiran-cho on the coast of Kagoshima Bay. MATERIAL EXAMINED . — Papua New Guinea • 2 sh ( 1 juv); New Ireland ; 2°44’S , 150°35’E ; 240-305 m depth ; 3.IX.2014 ; KAVIENG 2014 Stn DW4463; MNHN • 2 sh; New Ireland ; 2°43’S , 150°36’E ; 140-214 m depth ; 3.IX.2014 ; KAVIENG 2014 Stn DW4464; MNHN • 2 sh; New Ireland ; 2°43’S , 150°36’E ; 90-228 m depth ; 3.IX.2014 ; KAVIENG 2014 Stn DW4465; MNHN . DISTRIBUTION .— Maldives , Andaman, Thailand , Philippines , Japan , northern Australia , northeastern PNG , New Caledonia , Vanuatu , Fiji , Tonga ( Habe 1963 ; Hasegawa 2000 ; Pizzini et al. 2013 ; Vannozzi 2017 , 2019b , unpublished data). FIG . 2. — Caecum Fleming, 1813 species from deep-water stations from northeastern PNG: A , B , C. sepimentum de Folin, 1868 from Stn DW4463 ( B : juvenile); C , D , C. sepimentum from Mactan, Philippines, beached (coll. WR); E -H , C. vertebrale Hedley, 1899 from Stn DW3754; I , J , C. japonicum ( Habe, 1978 ) from Stn. DW4464; K , L , C. japonicum from Stn DW4463 ( L , juvenile); M , C. inflatulum Vannozzi, 2017 from Stn DW4463; N , C. inflatulum from Kotok, Indonesia, beached (coll. WR). Scale bar: 1 mm, details not to scale. DIAGNOSIS . — Shell of average size for the genus, whitish or colourless, usually showing brown and/or white bands arranged in collabral or zigzag pattern. Protoconch planorbid, multispiral of c. 2 whorls. Teleoconch tubular, arched, almost smooth. Early teleoconch conical, slightly twisted with very fine rings disappearing during the growth. Adult shell subcylindrical, smooth, tapering toward the apex, bent toward the aperture. Aperture simple, contracted, inclined. Septum low dome-shaped, slightly protruding without mucro, recessed below the cutting plane. Periostracum light brown, sometimes hairy. Operculum thin and flat. Animal described by Vannozzi (2019b) . Adult shell length c . 2.5 mm , protoconch size c. 360 µm. REMARKS Caecum japonicum is a widespread and common species, showing a variety of colour patterns that allow easy identification, although colourless specimens occur. Worn specimens appear white.