A new problematical Hygromiidae from the Aeolian Islands (Italy) (Pulmonata: Helicoidea)

22 Pages·1992·7.6 MB·English

MALACOLOGIA, 1992, 34(1-2): 107-128
A NEW PROBLEMATICAL HYGROMIIDAE FROM THE AEOLIAN ISLANDS
(ITALY) (PULMONATA: HELICOIDEA)1
Folco Giusti2 Giuseppe Manganelli2 & Jorge V. Crisci3
,
ABSTRACT
Helicotrichan. gen. is proposed foraverysmall hygromiid from theAeolian Islands, Italy: H.
carusoin. sp. The new species has a shell with persistent postembhonal hairs and is charac-
terized anatomically by: a right ommatophore retractor independent of the genitalia; a penial
nerveoriginating fromthe rightcerebral ganglion; avaginal complexwith digitiform glandsand
dart-sac complex consisting of two couples of stylophores disposed on opposite sides of the
vagina (each couple isformed by a largerdart-bearing outerstylophore and asmallerdartless
inner stylophore); and a penial complex with a very peculiar penial papilla. Direct anatomical
comparison of the new genus with other genera of the Hygromiidae suggested that it may be
very closely related to Microxeromagna. This hypothesis was subsequently found to be sup-
ported by the results of cladistic analysis. New evidence is thus provided to confirm that the
distinction between the Hygromiinae and theTrichiinae is artificial. A neotype is designated for
HelixaetneaBenoit, 1857,ajuniorsynonymofXerotrichaconspurcata(Draparnaud, 1801),and
the presence of Helicopsis (s. str.) in western North Africa is confirmed.
Keywords: Hygromiidae,Aeolian Islands, Italy,western Mediterranean, Helicella,Xerotricha,
Helicopsis, systematics.
INTRODUCTION the genus Helicopsis, details of the penial
complex suggested otherpossibilities. In par-
Recent insular equilibrium theory studies ticular, as in the case of Helicella (one large,
based on analytical comparison of the mala- evident and onevestigial, externally invisible,
cofaunasofthe Tuscan and Aeolian archipel- stylophore on opposite sides of the vagina)
agos, Italy (Piantelli et al., 1990), have moti- and Xerolenta (one normal and one modified
vated new field research and study of the stylophore on opposite sides of the vagina)
materialcollectedfromthevariousislands. As whichappeartoform monophyleticgroupsre-
happenedforthe islandsoftheTuscanArchi- spectively with Candidula (one large, evident
pelago (Giusti & Manganelli, 1989, 1990), and one vestigial, externally invisible, stylo-
new data emerged for the Aeolians. A new phore on one side of the vagina) and Xero-
species of the Hygromiidae was identified munda (one normal and one modified stylo-
amongst material of Xerotricha conspurcata phore on one side ofthe vagina) respectively
(Draparnaud, 1801) collected in all the Aeo- (Hausdorf, 1988, 1990a; Giusti & Manganelli,
lian Islands. The Hygromiidae are a group of 1989; Manganelli & Giusti, 1989), it seems
helicoids of western Palaearctic distribution highly probable that the new genus (one
recently separated from the Helicidae as a larger outer stylophore and one smaller dart-
distinct family and characterized by a bursa less innerstylophore on opposite sidesofthe
copulatrix duct free from the diaphragm wall vagina) is a member of the monophyletic
and a variable number of stylophores. group to which also Microxeromagna (one
Thepeculiarstructureofthegenitaliamade larger outer stylophore and one smaller dart-
it difficult to establish relationships and ge- less inner stylophore on one side of the va-
neric status ofthe new species. Although the gina) belongs. Accordingly, in viewofthefact
2 + 2 structure of the dart-sac complex as- that Helicella, Xerolenta, Candidula, Xero-
sociated with the vagina, and the right om- munda are unanimously regarded as distinct
matophore retractorfree of penis and vagina, generic taxa and in view also of our consid-
at first glance suggested a relationship with erations on character weighting in establish-
1NotulaeMalacologicae, LI.
2Dipartimentodi Biológica Evolutiva, Universitàdegli Studidi Siena, ViaMattioli4, 1-53100Siena, Italy
laboratoriodeSistemáticayBiología Evolutiva, MuseodeLaPlata, Paseodel Bosque 1900, LaPlata, Argentina
107
108 GIUSTI, MANGANELLI & CRISCI
ing systematic rank in the Hygromiidae (Man- bursa copulatrix free from diaphragm; vari-
ganelh & Giusti, 1988), a new genus is intro- able number of stylophores (2 + 2; + 2;
duced for the new species. 1 + 1; + 1; + 0); stylophores, when
presentand notextremely regressed or mod-
MATERIALS AND METHODS ified, forming dart-sac complex consisting of
one ortwo double units with a common base
Empty shells and whole specimens were and distinct distal sacs lying side by side in
collected in the litter or under stones and the same plane; diverticulum of bursa copul-
wood on rocky slopes of the islands (locality atrix absent; digitiform gland tufts variable in
datafollowsspeciesdescription). Livingspec- numberinsertedon proximalvaginanotclose
imenswereleftinwatertodrownfor24 hthen to where dart sacs, when present, open into
preserved in ethanol 75%. Relaxed material vagina. Helicidae are characterized by: bursa
was studied by optical microscopy (Wild copulatrix inserted into diaphragm; dart-sac
M5A). Bodies were isolated then dissected complex consisting of a single stylophore; di-
usingthin, pointed watchmaker'sforceps. Im- verticulum of bursa copulatrix duct present.
agesofisolated portionsofbodyandgenitalia Helicidae and Hygromiidae share the follow-
weredrawn using aWild camera lucida. Rad- ingcharacters: dart-saccomplex, vaginal dig-
ulae were manually extracted from buccal itiform glands.
bulbs, then washed in pure 75% ethanol, Twenty (Table 1) genera are considered to
mounted on copper blocks with electron-con- betheterminaltaxa. The minutedetailsofthe
ductive glue, sputter-coated with gold and distal genitalia of some have recently been
photographed using a P—hilips 505 SEM. reviewed (Schileyko, 1978a, 1978b; Giusti &
All shell parameters shell maximum di- Manganelli, 1987, 1989; Hausdorf, 1988,
ameter, shell height, ap—erture maximum di- 1990a, 1990b; Manganelli & Giusti, 1988,
ameter, aperture height were measured in 1989).
variable numbers of shells from the different In the case of the two sets of genera re-
islands using a Wild M5A microscope and a viewed by Schileyko and Hausdorf, some
millimetric lens. Whole shells were photo- characterswereuncertainornotdiscussed. A
graphed under optical microscope. Whole question mark sometimes follows or substi-
shells and shell surface details were photo- tutes the character states in Table 3. A ques-
graphed under optical and scanning electron tionmarkalsosubstitutesthecharacterstates
microscopes using the procedure described when one character is known to be present
forthe radulae. with more than two states in the same taxa
Detailed study of the genitalia followed, (character 5 in Xeromunda and Cernuella (s.
particularly the distal portion (penis and va- str.); character 16 in Xerotricha). Character
gina), the external and internal details of polaritywasdetermined byoutgroup compar-
which proved to be diagnostic characters in ison methods (Watrous & Wheeler, 1981;
similarpreviousstudies(see literaturecited in Maddison et al., 1984) using the family col-
the Discussion) (Table 2). lectively Helicidae as outgroup, because
Theentire setofcharacterstateswas used there is no singie genus that is a clear sister
for classical evolutionary and cladistic analy- group. Threeoutfifteen characters (5, 10, 15)
sis to define the new genus. had more than two character states. These
Cladistic analysis was performed using the characters were treated as nonadditive. Two
method of phylogenetic systematics as origi- characters (11, 14) were autoapomorphies,
nallydeveloped by Hennig (1966), who main- with an additional autoapomorphy in a multi-
tained that only strictly monophyletic taxa state nonadditive character (10).
may be regarded as historical entities and The data was analyzed using a Wagner
demonstrated that the only logical basis for parsimony algorithm from Farris's phyloge-
inferring monophyly is by showing synapo- netic program HENNIG86, applying the im-
morphies. The distribution ofthe synapomor- plicit enumeration option for calculating trees
phies is determined by the parsimony crite- (version 1.5; Farris, 1989; see also Platnick,
rion (minimizing homoplasy). On the basis of 1989) run on a IBM AT computer. When cla-
these synapomorphies, the taxa are ordered disticanalysisyielded morethanonetree, the
into a specific pattern represented by a hier- Nelsen consensus method was applied
archical branching diagram. (Nelsen, 1979). We also used the successive
The new genus Helicotricha belongs tothe weightingprocedure(Farris, 1989),whichcal-
family Hygromiidae, which is delimited by culates weights from the best fits to the most
the following unique combination of features: parsimonious trees, and applied them in the
A NEW HYGROMIIDAE FROM ITALY 109
TABLE 1. Acronyms, genus-group taxa, type species and bibliographical sources of anatomical data.
Some of the genera listed have a subgeneric division. For cladistic analysis, only species of
nominotypical subgenera have been considered.
Acronyms Genus-grouptaxa Type-species Sources
CAND Candidula Kobelt, 1871 Glischrus(Helix)candidula, Hausdorf, 1988: (. unifasciata,
Studer, 1820, = Helix . gigaxii);personal
unifasciata Poiret, 1801 unpublisheddataon spadae,
intersecta, unifasciata
CAUC Caucasigena Lindholm, 1927 HelixeichwaldiPfeiffer, 1846 Schileyko, 1978a, 1978b
CERN Cernuella Schlüter, 1838 Helixvariabilis Draparnaud, Hausdorf, 1988; Manganelli &
1801, = Cochlea virgata Giusti, 1988
DaCosta, 1778
EDEN Edentiella Polinski, 1929 Helixedentula Draparnaud, Schileyko, 1978a, 1978b
1805
HELL Helicella Férussac, 1821 Helixitala Linnaeus, 1758; cf. Hausdorf, 1988; Giusti &
Opinion431 Manganelli, 1989
HELP HelicopsisFitzinger, 1833 Helixstriata Müller, 1774 Giusti & Manganelli, 1989;
Schileyko, 1978b;
Hausdorf, 1990b
HELT HelicotrichaGiusti & HelicotrichacarusoiGiusti, this paper
Manganelli, 1992 Manganelli & Crista, 1992
HYGR Hygromia Risso, 1826 Helixcinctella Draparnaud, Giusti & Manganelli, 1987
1801
HYGH HygrohelicopsisSchileyko, Hygrohelicopsisdarevskii Schileyko, 1978a, 1978b
1978a Schileyko, 1978a
KOKO Kokotschashvilia Hudec& HelixholotrichaO. Boettger, Schileyko, 1978a, 1978b
Lezhawa, 1969 1884
LEUC Leucozonella Lindholm, 1927 Helixrubensvon Martens, 1874 Schileyko, 1978a, 1978b
MICR MicroxeromagnaOrtiz de Helixstolismena Bourguignat, Hausdorf, 1988, 1990c;
Zarate Lopez, 1950 in Servain, 1880, = Helix Manganelli & Giusti, 1988
armillata Lowe, 1852
NANA NanajaSchileyko, 1978b NanajacumulateSchileyko, Schileyko, 1978b
1978b
PLIC PlicuteriaSchileyko, 1978a HelixlubomirskiiSlosarski, 1881 Schileyko, 1978a, 1978b
PXER PseudoxerophilaWesterlund, Helix(Pseudoxerophila) Hausdorf, 1988
inWesterlund & Blanc, 1879 bathyteraWesterlund, in
Westerlund & Blanc, 1879
TRIC Trichia, Hartmann, 1840 Helixhispida Linnaeus, 1758 Schileyko, 1978a, 1978b
XERL Xerolenta Monterosato, 1892 Helixobvia Menke, 1828 Hausdorf, 1988
XERM Xeromunda Monterosato, Helixturbinate, sensu Hausdorf, 1988, 1990a;
1892 Monterosato, 1892, non De Manganelli & Giusti, 1989
Cristofori &Jan, 1832) (cf.
Hausdorf, 1988; Manganelli &
Giusti, 1988; 1989; an
applicationtothe I.C.Z.N, is in
progressbyGiusti & Manganelli
XERS Xerosecta Monterosato, 1892 Helixexplánala Müller, 1774 Manganelli & Giusti, 1988
XERT XerotrichaMonterosato, 1892 Helixconspurcata Draparnaud, Hausdorf, 1988; Giusti &
1801 Manganelli, 1989
weighting procedure until there were no right cerebral ganglion; vaginal complex with
changes in successively produced trees. digitiform glands and dart-sac complex con-
sisting of two pairs of stylophores, each cou-
SYSTEMATIC DESCRIPTION plecomprisingalargerdart-bearingoutersty-
lophore and a smaller dartless inner
Helicotricha n. gen stylophore; penial complex having a very pe-
Diagnosis culiar penial papilla.
Very small hygromiid with shell having per-
Description
sistent postembronial hairs; anatomically
characterized by right ommatophore retractor Shell: Small, hairy, opaque-brown in colour,
independent of genitalia; penial nerve from with white flecks. Spire consisting of approx-
GIUSTI, MANGANELLI & CRISCI
11
TABLE 2. List of characters
—
—1 Penial nerve.
—From right cerebral ganglion =
From right pedal ganglion = 1
Remarks: no datafor Caucasigena, Edentiella, Hygrohelicopsis, Kokotschashvilia, Leucozonella, Nanaja,
Plicuteria. In Manganelli & Giusti (1989: 4) was wrongly reported forXeromunda "from right pedal
ganglion." Revision of original data indicatesthat penial nerve comes out of right cerebral ganglion.
—
—2 Right ommatophore retractor.
—Between penis and vagina =
Independent of penis and vagina = 1
Remarks: No data for Psudoxerophila.
—
3 Number ofstylophores and/ortheir dérivâtes forming the dart-sac complex.
—2 + 2 =
—0 + 2 = 1
—
—4 Shape and position of stylophore groups in relation to vagina.
Stylophores Trichiatype: each stylophore group (each composed of an outer and an inner stylophore)
—slenderand entering vaginathrough a slender neck (Manganelli & Giusti, 1988: fig. 14 E) =
Stylophores not Trichiatype: each stylophore group (each composed of an outer and an inner
stylophore) wide and fused to innerwalls ofvagina for a long tract (Manganelli & Giusti, 1988: fig. 14 A)
=
1
Remarks: Helicopsis: based on the type species only (Giusti & Manganelli, 1989). Schileyko (1978b) and
Hausdorf (1990b) show drawings ofthe genitaliaof H. striataand of some otherspecies (H. likharevi, H.
retowskii) in which the situation is slightlydifferent. Aslightly different situation also occurs in the species
studied in the present paper and referred to as Helicopsissp.
—
—5 Shape and dimensions of stylophore groups.
Each groupformed by an inner and an outerstylophore of similar dimensions (Manganelli & Giusti,
—1988: fig. 14 A) =
Each group consisting of large outerstylophore and small externallyvisible innerstylophore (Giusti &
—Manganelli, 1989: fig. 9 A) = 1
Each group consisting of large outerstylophore and externally visible residues ofthe innerstylophore
—(Manganelli & Giusti, 1989: fig. 1 E) = 2
Each group consisting of largerouterstylophore and very small, not externallyvisible, inner stylophore
—(Schileyko, 1987a: fig. 43) = 3
Each group consisting of large outerstylophore and extremely reduced not externally visible inner
stylophore (Giusti & Manganelli, 1989: fig. 9 C) = 4
Remarks: the scheme ofthe dart-sac complex in Helicella reproduced by Hausdorf (1988: fig. 8) is
incorrect: the inner stylophore, referred to as "Nebensack," appears too large and externally visible.
—
—6 Digitiform glands.
—All around vagina =
On one side of vagina = 1
Remarks: situation not clear enough in drawings by Schileyko (1978a, 1978b) ofthe genitalia of
Edentiella, Nanaja and Plicuteria. The situation in Hygrohelicopsis and Leucozonella showed bythe
same author (Schileyko, 1978a, 1978b) seems to indicate digitiform glands all around vagina. Species of
Cernuella (s. str.) show digitiform glands all around vagina (C. caruanae) oron one side ofthe vagina
(C. virgata).
—
—7 Basal portion
Stylophore groups opening directly into vaginawithout a wide basal dilated portion (Manganelli &
—Giusti, 1988: fig. 14 E) =
Stylophore groups opening in awide dilated basal portion (Manganelli & Giusti, 1989: fig. 1 E) = 1
—
—8 Innerstylophores.
—With thin muscularwalls and large internal cavity (Manganelli & Giusti, 1988: fig. 14 E) =
With thick muscularwalls and small internal cavity (Manganelli & Giusti, 1988: fig. 14 A) = 1
Remarks: transverse and longitudinal sections ofdart-sac complex in Edentiella, Kokotschashvilia,
Leucozonella, Nanaja, Plicuteria unknown. Situation as reported by Schileyko (1978a, 1978b) for
Caucasigena and Hygrohelicopsis notclearenough.
1
A NEW HYGROMIIDAE FROM ITALY
11
—
—9 Opening of stylophores.
Openings of inner and outer stylophore cavities into vagina close to each other (Manganelli & Giusti,
—1988: fig. 14 E) =
Openings of inner and outer stylophore cavities into vagina very far apart (Manganelli & Giusti, 1988:
fig. 14 A) = 1
—
—10 Innervaginal accessory structures.
—Opening of stylophores in a groove bordered by folds (Manganelli & Giusti, 1988: fig. 8 A) =
—Opening of stylophores bordered by rows of papillae (Schileyko, 1987b: fig. 215) = 1
Vagina with one tongue-like structure for each stylophore group (two tongue-like structures when 2
—stylophore groups present) (Giusti & Manganelli, 1989: figs. 3, 9A) = 2
Vagina with a groove-like structure for each stylophore group (unique tube-like structure when 2
stylophore groups present) (Giusti & Manganelli, 1989: figs. 7, 9 C) = 3
—Vaginawith dart-gun through which dart is shoot (Manganelli & Giusti, 1989: figs. 4 E, 14 A) = 4
—
—11 Jointof penis and vagina
—Penisjoins vagina distally with respect to stylophores (Manganelli & Giusti, 1989: Fig. 5 F) =
Penisjoins distal vagina level with stylophores (Manganelli & Giusti, 1989: fig. 8 B) = 1
—
—12 Proximal penis.
Proximal penis Helicopsis type: transverse sections reveal a duct in the lumen; this duct joins the
epiphallus lumen directly with the ejaculatory canal ofthe penial papilla (Giusti & Manganelli, 1989: fig. 8
—F, H) = 0.
Proximal penis simple: transverse sections only show the penial walls (Manganelli & Giusti, 1988: fig.
11 F) = 1.
Remarks: A structure, only apparentl,y similar to those in Helicopsis, seems present in drawings by
Manganelli & Giusti (1990: figs. 2C, 4E for Xeromunda), Schileyko (1978b: Fig. 253 for "Helicella
candicans)", Schileyko, in Damjanov & Likharev (1975: fig. 274, for "Helicella candicans" and fig. 278 for
"Helicella spiruloides"). This is due to the fact thatthe thin external layer of the penis has been detached
during dissection.
—
—13 Glandular area on one side ofterminal penis walls.
absent =
—
present (this paper: Fig. 3) = 1
Remarks: no data for Caucasigena, Edentiella, Hygrohelicopsis, Kokotschashvilia, Leucozonella, Nanaja,
Plicuteria, Pseudoxerophila;for Microxeromagna unpublished personal data.
—
—14 Frenula.
Penial papilla with no frenula joining it to the distal penis walls (Manganelli & Giusti, 1988: fig. 7 F-H)
=
—
Penial papillajoined byfrenulato the distal penis walls (Manganelli & Giusti, 1988: fig. 6 C-D) = 1
—
15 Sections of penial papilla.
——Trichiatype (Schileyko, 1978b: fig. 221) =
Caucasigenatype (Schileyko, 1978b: fig. 199) = 1
——Xerosectatype (Manganelli & Giusti, 1988: fig. 8 C) = 2
—Helicotrichatype (this paper: Fig. 3C) = 3
Microxeromagnatype (Manganelli & Giusti, 1988: fig. 11 E) = 4
—Leucozonellatype (Schileyko, 1978b: fig. 146) = 5
—Cernuellatype (Manganelli & Giusti, 1988: fig. 7 G) = 6
Remarks: Species of Xerotricha have sections of penial papilla of Trichia type (X. apicina) and of
Cernuellatype (X. conspurcata). Due to variability, Leucozonella is based onlyon the type-species.
¡mately 4 whorls separated by deep sutures, sisting of fine close longitudinal grooves. Ex-
last whorl angled at periphery. Umbilicus ternal surface ofteleoconch with superficially
open, wide approximately 1/5 of maximum reticulated periostracal layer and transverse
shelldiameter. Apertureoblique, oval, lacking rows of very short hairs,
internal rib. Peristome not thickened or re-
flexed. External surface of protoconch with Genitalia:Vaginalcomplexwith relativelylong
fewfaintgrowth linesand microsculpturecon- distal vagina; dart-sac complex consisting of
112 GIUSTI, MANGANELLI & CRISCI
TABLE 3.
treated as
A NEW HYGROMIIDAE FROM ITALY 113
FIG. 1. Shells of Helicotricha carusoin. gen. n. sp. Holotype (A) and one paratype (B) from Alicudi Island:
Perciato, F. G. leg. 24.10.69. A shell from Salina Island: Pollara, R. Arcidiacono leg. 21.9.66 (C).
—
Helicopsissp., Piantelli et al., 1990: Table 5 Whiteflecks widely distributed over shell sur-
et passim. face, concentrated above (near sutures and
nearperipheryoflastwhorl)toformirregularly
Diagnosis spaced spots of variable shape, below (from
periphery of last whorl to umbilicus) to form
At present the only species of the genus white spiral bands ofvariablewidth and num-
Helicotricha known. Specific coincides with
ber(2-6).Spiredepressed-conical,consisting
generic diagnosis.
of 4-4V2 convex, regularly increasing whorls
separated by deep sutures; last whorl angled
Description
at periphery, dilated, sometimes descending
Shell (Figs. 1A-C, 2A-D): Shell small (Figs. slightly near aperture. Umbilicus open and
1A-C), hairy, low conical above, convex be- wide, approximately 1/5 of maximum shell di-
low,opaquebrownincolour,withwhiteflecks. ameter.Aperturemarkedlyoblique,oval,lack-
114 GIUSTI, MANGANELLI & CRISCI
FIG.2. ExternalshellsurfaceofspecimensofHelicotrichacarusoin.gen.n.sp.collectedonPanareaIsland,
D.Caruso& I. Marcellinoleg.27.5.67(A-B)andLipari Island:MonteSantAngelo, F.G. leg.23.10.69(C-D).
A:Aviewoffirstwhorls. B: Detailofprotoconchshowinglongitudinalgrooves.C:Detailoflastwhorlwithone
hairand reticular microsculpture ofteleoconch. D: Detail of reticular microsculpture ofteleoconch.
ing internal rib; peristome not thickened, 2C-D), superficially reticulated (Fig. 2D) to
slightly reflexed at its columellar margin. form transverse rows of very short, often
External surface of protoconch with few hook-shaped hairs0.1 mm in length (Fig. 2C).
faint growth lines near its end (Fig. 2A) and Reticulation and hairs of caducous appear-
microsculpture consisting of fine close spiral ance, absentin large portionsofsurface. Sur-
grooves (Fig. 2B). External surface of teleo- face of mineralized portion of shell (in areas
conch (Fig. 2A) with manygrowth lines, more devoid of periostracal layer) seems to be
marked near sutures. Periostracal layer (Fig. crossed by fine close spiral grooves.
A NEW HYGROMIIDAE FROM ITALY 115
FIG. 3. Genitaliaof Helicotrichacarusoin. gen. n. sp. in specimens collected on Basiluzzo Islet, F. G. leg.
5.11.69. A-B: Two oppositeviewsofthe same genital apparatus (gonad excluded in A; gonad and partof
ovispermiduct excluded in B). C: Part of penial complexwith distal penisopened to show penial papilla, a
section of proximal penis and two sectionsof penial papilla. D: Vaginaopened to show its innerstructure.
Explanations ofthe symbols used in Figures 3-5, 8: ag, albumen gland; be, bursa copulatrix (gametolytic
gland); dbc, duct of bursa copulatrix; dg, digitiform glands; dsc, dart-sac complex; dp, distal penis; e,
epiphallus;f, flagellum;fc,fertilizationchamber;fn, fenestration;fo,freeoviduct;fr,frenula;g, penial papilla
(glans); ga, genital atrium; gp, genital pore; gt, glandular tissue; gtp, gland of the terminal penis; hd,
hermaphroditeduct; p, penis; po, prostatic portionofovispermiduct; pp, proximal penis; pr, penial retractor
muscle;pv, proximalvagina;pw, penialwall;s, stripes;sr, seminalreceptacle;t,talon;tsp,t-shapedpilaster
ofthe penial papilla; uo, uterine portion ofovispermiduct; v, vagina; vd, vas deferens.
116 GIUSTI, MANGANELLI & CRISCI
FIG.4.GenitaliaofHelicotrichacarusoin.gen. n.sp.inspecimenscollectedonFilicudi Island:Stimpagnato,
F.G.leg.28.10.69.A:Genitalapparatus(gonadandpartofovispermiductexcluded).B-C:Partoftwopenial
complexeswith distal penisopenedtoshow penial papilla, section ofepiphallus, proximal penisand penial
papilla (B), Section of proximal penis and two sections of penial papilla (C). D: Vaginaopened to show its
innerstructure.
Dimensions (N = 10): shell max. diam.: diam.: 5.3 mm; shell height: 2.8; aperture
4.5-5.4 mm; shell height: 2.5-3.4; aperture max.: diam. 2.1 mm; aperture height: 2.1
max. diam.: 2.0-2.5 mm; aperture height:
1.7-2.1. Genitalia (Figs. 3A-D, 4A-D, 5A-D, G): Con-
Dimensions of the holotype: shell max. voluted first hermaphrodite duct arising from