The malacologicalsocietymalacological society of Japan R# VENUS (Jup. Jour Malac.) Vol. 4S, No. 2 (1989):S5...95 r J< v; I; lf' a)}lfMtrcv)Li-( L ft ,im Generie Position of Kaliella･ yaeya･mensis Pilsbry, 1901 (Pulmonata: Helicarionidae) Rei UEsHIMA (Institute of Biolog'ical Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan 305) Abstract: Live materials of a helicarionid speeies Kaliellct yaeyamensis eollected from various localities <ineluding its type locality) were examined and its genital and radular features are deseribed. Although the present speeies has been assigned to the genus Para･kaliella of the tribe Eueonuli, subfamily Euconulinae, this species is transferred to the genus Liardetia (s,s.) of the tribe Mierocysti of the same subfamily on the basis ef genital and eon- chological features, L. yaeyameresis distributes at least from Ryukyu Islands to Caroline Islands through Formosa. As several related taxa, probably eonspecifie, are known from various loealities, its distribution range would be extended further. Local differentiation within this speeies is reeognized from the morphological variation in the penial stimulator. Introduction Katiella･ yaeyamensis Pilsbry, 1901 is a small helicarionid described from Yaeyama Islands and reported also from Formosa (Pilsbry 1905). This species, as well as other Japanese minute helicarionids, was first alloeated in the genus "widely KaLiella whieh was thought as a distributed" genus at that time (Pilsbry 1901). Habe's (1946,1957) anatomical studies revealed that Japanese heli- carionids formerly classified in Kalietta actually belonged to distinet groups. ``Kalielta" Following Habe's view, Kuroda (1958) divided -Japanese into two groups; Trochoehtamys Habe 1946 and ParakalieUa Habe 1946, and he pointed "Kalietta" out that yaeyamensis was conchologically distinguishable from those two groups. However, Kuroda (1963) later plaeed this speeies in Parakalielta without any explanation and this alloeation has been followed by subsequent authors (Azuma 1982, Minato 1988). During the review of Japanese Helicarionidae, many live speeimen$ of this species available for anatomieal studies were eollected not only from the type NII-Electronic Library Service The malacological society of Japan 86 VENUS: VoT. 48, No.2(1989) Ut 2 E PRM HG Ep × EC B PRM 1 PA/ VD -- Ut ."iEC---" PA - NII-Electronic Library Service The malacologicalsocietymalacological society ofJapanof Japan Ueshima: Generic position of Kalielta yaayamensis 87 loeality, but also from Minami-Daito Island and Formesa. Although the present species has been assigned to Parcticatiella which belongs to the Tribe Euconuli ef the subfamily Euconulinae, its genital features indicate that the present species is a member of the Tribe Microcysti of the same subfamily. Therefore, the present speeies eannot be retained in ParakalieZla, The following account presents this evidenee and provides anatomical features of this species and new generic assignment. Materials and Methods Materials dissected: Ishigaki Island, Yaeyama Islands: Mt. Omange, Hoshino (37 specimens, 30 Mareh 1984); Nagura (3 specimens, 31 Mareh 1984); Palm Park, Yonehara (2 specimens, 31 Mareh 1984). Iriomote Island, Yaeyama Islands: Nakano (26 specimens, 28 March 1984) ; Toyohara (2 specimens, 27 Mareh 1984). Minami-Daito Island, Daito Islands: Kyuto (12 specimens, 5 November 1986, collected by T. Kurozumi). Forrnosa (Taiwan): Ken-Ting Park (6 specimens, 22 August 1985); Cape Wolanpi (1 speeimen, 20 August 1985). General methods of dissection and scanning electron micrograph were carried out according to the methods described in Ueshima and Kurozumi (1988), except several specirnens collected from Ishigaki Island which were dissected alive in a saline. Observations Genitat-ia (Figs. 1-4) : Hermaphroditic gland (ovotestis) is small, censisted of mainly two clusters of clavate alveoli (each cluster is sometimes divided further into two in large specimens as shown in Fig. 2), embedded in mid-gut gland. Hermaphroditie duct is slender, rather short, weakly convoluted. Talon is small, frequently albumen small embedded in gland. Carrefour is but prominent. AIbumen g}anq is triangular, rather small for heliearionids, eonsisted of large.loosely cemented cells. Uterus is well developed, extremely swollen by pregnancy. Upper region ttttt tttttt tttt t ttt t tt tttt-tt Figs. 1-3. Genital organs of Liardetia (s,s.) yaayamensis. =JK t; }= tfOthdeX 1. Mt, Omange, Hoshino, Ishigaki, Island (showing an individual dissected alive in a saline) ; 2. Cape Wolanpi, Formosa ; 3. Kyuto, Minami-Daito Island (A. showing the natural condition in which penial complex is compactly folded and surrounded by a thin sheath; B. penial complex with its sheath cut out). Scale line 1 mm, AG, albumen gland; At, atrium;BC, bursa copulatrix;C, carrefour;Em, emryo; EC, epiphallic caecum; Ep, epiphallus; HD, hermaphroditic duct ; HG, herma- phroditic gland or ovotestis; P, penis; PA, penial appendix; Pr, prostate; PRM, penial retractor muscle ; PUO, post-uterine oviduct ; T, talon ; Ut, uterus ; VD, vas deferens. NII-Electronic Library Service The malacologicalsocietymalacological society ofJapanof Japan 88 VENVSt VoL 48, No. 2 (1989) = =}' Fig. 4.Internal structures Qf penis of Liardetia (s.s.) yaayamensis. X t; ifDltgCDNutIYue A. a typical specimen collected from Ken-Ting Park, Formosa ; B, C. specimens with secondary horny stimulator collected from Kyuto, Minami-Daito Island ; D. a specimen with large beaky horny stimulator but no secondary stimulator collectedfrom Kyuto, Minami-Daito Island. Scale bar 250 ptm in A, 100 pm in B, C and D. BHS, beaky horny stimulator; EC, epiphallic caecum; PA, penial appendix; PPd, penial pad ; SHS, secondary horny stiTnulator ; VD, vas deferens. NII-Electronic Library Service The malacologicalsocietymalacological society of Japan Ueshima: Generic positien of Kolietla yaq),amensis 89 of uterus which attaches to prostate is small, slender, defiated, always empty, refiexed backwards at the end of prostate and then becomes abruptly swollen to contain eggs or embryos. This embryo-containing region (cerresponding to free oviduct of other helicarionids) is large, thin-walled, completely separated from sperm duct, and followed by empty regiQn called post-uterine oviduct (Baker 1938). Post-uterine oviduct is slender, thin-walled, does not have glandular zone nor internal pilaster. This species is ovoviviparous, All examined specimens ineluding young materials have one to ten eggs or embryos in uterus. Eggs in uterus do not have ealcareous shell nor outer layer, Embryos become progressively grown from top to bottom and the largest embryo found near the gonopore has about 2 whorls. Prostate is small for helicarionids, consisted of numerous acini, contjnues from carrefour to the beginning of vas deferens. Vas deferens is slender, simple, entering the apex of epiphallus beside the epiphallic caecum. Epiphallus is slender, s!ightly broader than vas deferens, 'is with a prominent epiphallic eaeeum. Basal region of epiphallus which re- cognizable from outside as opaque white region has much gland eells than other region and is probably homologous to eorona of Philonesiae (Baker 1938). Epiphallic caeeum is large, about twice the diameter of epiphallus, inwardly eurved, with rounded apex, having ne prominent strueture internally. Penial retraetor muscle arises from the diaphragm, and inserts on the apex of penis. Penial appendix loeating near the insert,ion of penial retracter muscle is short but more slender when the animal is living (Fig. 1), tapers towards its apex, lacking pilaster or stimulator int,ernally. In a single specimen eolleeted from !shigaki Island, penial appendix is found to be everted. Upper half of penis is rather slender, having weak internal pilasters in several speeimens. Mid portion of penis is swollen, thick-walled, internally containing horny stimulator and one or two large penial pads (Fig. 4). Beaky horny stimulator whieh locates just below the penial pad is small, inwardly curved and its tip is peinting towards gonopore. As this beaky stimulator is found in all specimen examined and attaehing to the thick wall of penis tightly, this structure is probably persistent. In most of the specimens collected from Minami-Daito Island, a secondary horny stimulater is found just above the beaky stimulator. Thi's secondary stimulator is large, recurved, with blunt or truncated tip. The phenb- type with the secondary horny stimulator is dominent in Minami-Daito Island but is never found in other localities. Basa} region of penis is rather slender, thin-walled, lacking pilaster or stimulator internally. A thin sheath attaching around the mid portion ef penis surrounds upper half of penis, penial appendix, epiphallus and epiphallic caecum that are eompactly folded (Fig. 3A). This sheath called penis sheath by Baker (1938) seems not to be homologous to thick muscular penis sheath of higher helicarionids whi ¢ h surrounds only a part of penis or epiphallus (this sheath is cut off and not shown in Figs. 1, 2, 3B, so NII-Electronic Library Service The malacologicalsocietymalacological society of Japan 90 VENUS: VoL 48, Ne. 2 (1989) Fig. 5. Radula ef Liardetia (s, s.) yaeyamensis: showing a specimen collected from Mt. Omange, Hoshino, Ishigaki Island, = A i} } tfOta= A. marginal teeth ; B. central teeth and latero-marginal transition showing the shape of basal plates ; C. outermost marginal teeth ; D. central teeth and latero- marginal transition in slightly worn rows. Scale