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 Mauroceras kajiyamai ( Habe, 1963 ) ( Fig. 8 A-C) Meioceras kajiyamai Habe, 1963: 235 , fig. 5. Mauroceras kajiyamai – Vannozzi 2023: 431 , and synonymy therein. TYPE MATERIAL . — Holotype . Japan • sh; Ankyaba , Kakeroma Jima , near Amami-Oshima ; NMST . TYPE LOCALITY . — Pacific Ocean, Japan , Ankyaba, Kakeroma Jima, an isle near Amami-Oshima. MATERIAL EXAMINED . — Papua New Guinea • 2 sh ( 1 juv); Vitu Islands ; 4°37’S , 149°27’E ; 615-647 m depth ; 27.IX.2010 ; BIOPAPUA Stn DW3680; MNHN • 1 sh; New Ireland ; 2°43’S , 150°36’E ; 90- 228 m depth ; 3.IX.2014 ; KAVIENG 2014 Stn DW4465; MNHN . DISTRIBUTION. — The whole IWP, from the eastern coast of Africa to Maldives , Philippines , PNG , Japan , New Caledonia ( Habe 1963 ; Hasegawa 2000 ; Pizzini et al. 2013 ; Vannozzi 2017 , 2019 a , b, 2023, unpublished data). DIAGNOSIS . — Shell of average size for the genus, colourless, semitransparent, glossy. Protoconch planorbid, smooth, of 1.75 whorls, ending with thickened sinusigera lip. Teleoconch openly coiled, tubular. Early teleoconch rapidly growing forming an open spiral like a cow’s horn, with sharp uniform rings becoming flat and hardly visible adapically. Adult shell subcylindrical, tapering toward both the apex and the aperture. Maximum width located adapically at about ¼ of the length. Septum recessed below the cutting plane, with a strong mucro, showing a straight dorsal side and a sloping, slightly convex ventral side. Aperture simple with reflected lip. Operculum and soft parts unknown. Adult shell length c. 3 mm , protoconch size 300 µm. FIG . 8. — Mauroceras Vannozzi, 2019 species from deep-water stations from northeastern PNG: A , B , M. kajiyamai ( Habe, 1963 ) from Stn CP3680 ( B , juvenile); C , M. kajiyamai from Stn DW4465; D , E , M. rhinoceros ( Pizzini, Raines & Vannozzi,2013 ) from Stn DW4470; F , G , M. serratum ( Vannozzi, 2017 ) from Stn DW4465 ( G , growth stage). Scale bar: 1 mm. REMARKS This species is widespread and shows little variability. The specimens from PNG show no differences with respect to specimens from other IWP localities.