An intergeneric hybrid (Gastropoda: Caenogastropoda: Strombidae) with remarks on the subdivision of Indo-Pacific Tricornis.

Abstract

A supposed hybrid of the strombid genera Sinustrombus and Lambis is reported upon. It is compared
with the supposed parental species. Based on literature records, a list of reported hybrids within the family Strombidae is provided. Some recently described genus level taxa within the Strombidae are briefly addressed.

Full text

An intergeneric hybrid (Gastropoda: Caenogastropoda: Strombidae) with
remarks on the subdivision of Indo-Pacific Tricornis
Gijs C. KRONENBERG
Milieu Educatie Centrum, P.O. Box 435, NL-5600 AK Eindhoven, The Netherlands
adsl711249@telfort.nl
A supposed hybrid of the strombid genera Sinustrombus and Lambis is reported upon. It is com-
pared with the supposed parental species. Based on literature records, a list of reported hybrids
within the family Strombidae is provided. Some recently described genus level taxa within the
Strombidae are briefly addressed.
Key words: Gastropoda, Strombidae, Tricornis, Lambis, hybridisation.
DEDICATION
About 25 years ago I had contact with Dr. Edi Gittenberger for the first time. This was
when I had the opportunity to examine the collection of Strombidae at the Rijksmuseum
van Natuurlijke Historie, then still in the old building at the Raamsteeg in Leiden. At that
moment I would never have believed that 20 years later I had the honour to serve in the
EDI-torial board of Vita Malacologica together with Dr. Gittenberger.
But before that I had to suffer from his editorial pen. One of these occasions was after
submitting a paper for Vita Marina (Kronenberg, 1993). As that paper was on a supposed
hybrid of two species of the genus Lambis Röding, 1798, it seems appropriate to dedicate
this contribution, also on a supposed hybrid, to Dr. Gittenberger, commemorating his
retirement from active duty in the very same museum where we first met.
INTRODUCTION
Before viable hybrids are born or hatched, a lot of barriers have to be crossed, see
Dubois (1988). This must also be true for molluscs. Yet, supposed hybrids within Mollusca
have been reported in literature (Kronenberg, 1993 and references therein); not only lim-
ited to the Recent fauna but probably also in the fossil record e.g. for Melanopsis
(Cerithoidea) (Geary, 1992) -and still occurring (Heller et al., 2005). Hybridisation is prob-
ably not restricted to gastropods. For instance Voskuil & Onverwagt (1990) reported on a
possible hybrid in Acanthocardia (Bivalvia, Cardiidae). Hybrid offspring can be fertile (see
e.g. Owen et al., 1971; and Mello-Silva et al., 1998).
The first to report a possible hybrid within the family Strombidae was Wolfe (1974)
on a presumed hybrid of Lambis crocata crocata (Link, 1807) × L. scorpius scorpius (Linnaeus,
1758). Since that paper, Kronenberg (1993) discussed specimens with characters interme-
diate between L. millepeda (Linnaeus, 1758) and L. trunctata sebae (Kiener, 1843). These had
earlier been described as L. arachnoides Shikama, 1971, and were at that time better known
as L. wheelwrighti Greene, 1978. In that paper Kronenberg concluded that there was no
proof of hybridisation, but that data strongly suggested the possibility of hybridisation.
Since that paper a large number (far over 500) of this supposed hybrid have become
known, and they appear rather frequently on the commercial market, so reproduction
with fertile offspring may also occur among these possible hybrids. This matter requires
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332 BASTERIA, Vol. 72, No. 4-6, 2008
Hybrid Alias Source #
Doxander vittatus
× D. campbelli
Man in ‘t Veld & Visser, 1993: pl. 3 figs 6, 6a 1
Euprotomus bulla
× E. chrysostomus
Liverani, 2002 2
Euprotomus bulla
× E. vomer
E. hirasei Kuroda, 1942 3
Kronenberg, 1999
Kronenberg, 2002
Euprotomus bulla
× E. aratrum
J.P. Barbier, pers. comm.
Photograph seen
1
Harpago c.chiragra
× Lambis lambis
De Turck et al., 1999: pl. 30 fig. 2 4
Kronenberg, 2008: 530, pl. 210
Lambis c. crocata
× L. s. scorpius
Lambis gaspardi* Wolfe, 1974 >100
Springsteen & Leobrera, 1986: 69, pl. 16, fig. 7
De Turck et al., 1999: pl. 31 figs 1, 2
Thach, 2007 : 18, fig. 38
Kronenberg, 2008: 534, pl. 212
Lambis c. crocata
× L. lambis
De Turck et al., 1999 : pl. 30 fig. 1 ?
Thach, 2007 : 18, fig. 37
Kronenberg, 2008: 532, pl. 211
Lambis lambis
× L. millepeda
Kronenberg, 1993: 54, pl. 3 figs 5a, 5b > 100
De Turck et al., 1999: pl. 32 fig. 3
Kronenberg, 2008: 530, pl. 210
Lambis lambis
× L. s. indomaris
Lambis christinae Bozzetti, 1999 4
Bozzetti, 2006
Lambis lambis
× L. s. scorpius
De Turck et al., 1999: pl. 30 fig. 4 ?
Thach, 2007 : 18, fig. 36
Kronenberg, 2008: 536, pl. 213
Lambis millepeda
× L. truncata sebae
L. millepeda Kurz, 1970
(non Linnaeus, 1758)
L. arachnoides ;
L. wheelwrighti
[Kurz, 1970] > 500
Shikama, 1971
Gary, 1974
Greene, 1978
Collins, 1980
Leobrera, 1980
Springsteen & Leobrera, 1986: 69, pl. 16, fig. 2
Kronenberg, 1993
De Turck et al., 1999: pl. 32
Kronenberg, 2008: 528, pl. 209
Lambis millepeda
× L. s. scorpius
De Turck et al., 1999: pl. 31 fig. 3 ?
Kronenberg, 2008: 536, pl. 213
Lentigo lentiginosus
× L. pipus
Kronenberg, 2008: 564, pl. 227 1
Sinustrombus latissimus
× S. sinuatus
Thach, 2007: 18, fig. 35 ± 5
Kronenberg, 2008: 544, pl. 217
Sinustrombus sinuatus
× S. taurus
Bob Abela, Guam, pers. comm.
Photograph seen
1
Lambis lambis
× Sinustrombus latissimus
Herein 1
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more research.
Since the Kronenberg (1993) paper, some more presumed hybrids within the family
Strombidae were reported upon. Bozzetti (1999 and 2006, as L. christinae, but the illustra-
tions show a specimen with characters intermediate between L. scorpius indomaris Abbott,
1962 and L. lambis (Linnaeus, 1758)); De Turck et al. (1999); Kronenberg (1999 and 2002);
Liverani (2002); and more recently Thach (2007); and Kronenberg in
Poppe (2008), dis-
cussed, or illustrated specimens of supposed hybrid origin.
An overview of supposed strombid hybrids known (taken from literature) is pre-
sented in table 1. So far thirteen of these hybrids have been reported upon in literature,
most of them only by images. Another supposed hybrid, Euprotomus aratrum (Röding,
1798) × Doxander vittatus apicatus (Man in ‘t Veld & Visser, 1993) (Thach, 2007: 18, fig. 39)
is not recognised here, as this specimen only appears to be an aberrant, high spired spec-
imen of E. aratrum. Only the hybrids Euprotomus bulla (Röding, 1798) × E. chrysostomus
(Kuroda, 1942) reported by Liverani (2002); E. bulla × E. vomer (Röding, 1798), first
described as Strombus hirasei Kuroda, 1942 reported by Kronenberg (1999); Lambis millepe-
da × L. truncata sebae; and L. lambis × L. scorpius indomaris (Bozzetti, 1999) have been dis-
cussed in detail.
Soon after the publication by Thach (2007) the present author became aware of anoth-
er possible hybrid within the family Strombidae. Subsequently Dr. Thach made this spec-
imen available for study. This specimen is described and discussed herein. During the
preparation of this paper the author became aware two more supposed hybrids (pers.
comm. Jean-Pierre Barbier and Bob Abela), totalling the number of supposed hybrids
within Strombidae to sixteen.
During the preparation of this paper, two papers (Bandel, 2007 and Dekkers, 2008)
were published that described genus level taxa that were to be addressed briefly in this
paper. As names for these taxa, from both Bandel (2007) and Dekkers (2008) are available
now, these genus level taxa are discussed further below.
DESCRIPTIVE PART
Lambis lambis (Linnaeus, 1758) × Sinustrombus latissimus (Linnaeus, 1758) (figs 1-4)
Description. — Shell large, length including digits and anterior canal 184.4 mm.
Protoconch worn off. Teleoconch with about 9 whorls, spire regularly coiled, not truncat-
ed. Spire on adapertural side largely covered by callous. First teleoconch whorl not cov-
ered, angled at shoulder, with calcareous deposit on it. Second whorl with close spaced
axial folds, on the fourth whorl gradually transformed into, initially indistinct, shoulder
knobs. From fourth whorl onward whorls concave. Fifth whorl with eight shoulder knobs
discernable on half of whorl, other half covered by callus, subsuturally with numerous
fine spiral lines, also present on shoulder knobs, suture of subsequent whorl running over
shoulder knobs, just abapical of shoulder. Indistinct subsutural cord present from fifth
whorl onward. Shoulder knobs gradually increasing in size, numbering six on sixth whorl
at 50% of whorl covered by callus, eight on seventh whorl, visible on three quarters of a
whorl. On the eighth whorl suture of last whorl set slightly adapical of shoulder knobs at
333Kronenberg: An intergeneric hybrid in the Strombidae
Table 1. Records of (supposed) hybrids within Strombidae, taken from literature, with an estimate of
numbers of hybrids known (#). The supposed hybrid Euprotomus aratrum x Doxander vittatus (Thach,
2007: 18, fig. 39) is omitted, as this specimen appears to be a malformed E. aratrum (Röding, 1798). Names
of supposed hybrids appearing in literature are included.
* The name Lambis gaspardi is a nomen nudum and has appeared only on the Conch-L discussion site.
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334 BASTERIA, Vol. 72, No. 4-6, 2008
Figs 1-5. 1-4, supposed hybrid Lambis lambis (Linnaeus, 1758) x Sinustrombus latissimus (Linnaeus, 1758)
Vietnam, Binh Thuan province, approx. 250 km south of Nha Trang, by local fishermen at 15 – 20 m, sum-
mer 2007. Actual length, including digits and anterior canal 184.4 mm, author’s collection reg. no. 6331;
1. Apertural view; 2. Dorsal view; 3 Lateral view; 4. Apical view. 5. Sinustrombus latissimus (Linnaeus,
1758) Philippines, no further data. Actual width 128.8 mm. Note adcolumellary strongly bent outer lip,
visible as a gutter in photograph. Photographs by Jeroen Goud.
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adapertural side of the spire. The eighth whorl also shows marks of a large injury, just
adapical of the sutue of the last whorl. On the last whorl the abapertural side of the shell
with four rather large but low shoulder knobs, penultimate knob highest, last one being
very low. Abapically of the shoulder, also at the abapertural side two mote rows of knobs,
the adapical one with three knobs, the last one ot that row connected with the penultimate
one of the shoulder knobs, the adbasal one with would better be referred to as a very low
indistinct cord with two very low knoblets. Indistinct spiral cords present all over the dor-
sal side of the shell.
Outer lip widely dilating with 12 projections (digits), first two broken off due to thin-
ness of that part of the outer lip, third very short seemingly from the same starting point
as the fourth. The third digit has rather an open, lobe-like character as a (closed) digit-like
character. This lobe-like character is supposed to be present in the first two projections as
well. With the fourth digit the process of forming a tube (to be subsequently filled by the
animal with inner shell material is becoming visible. Fourth, fifth and sixth digit project-
ing abbasal, (almost) parallel with the shell’s axis. Tip of fourth digit broken off, fifth digit
longest. Seventh digit very small, hardly developed. From the eighth digit onward, digits
become more solid. Eighth digit still an open tube, but digits nine to twelve, that are very
short, at stages of closing the tubes. Especially digit eleven is very short. Strombid notch
deep and broad with three, obsolete, rounded triangular projections, flange between
strombid notch and anterior canal with four, even less developed triangular projections.
Anterior canal distinct but short, no traces of parts being broken off. Adapertural side of
outer lip and columellar callus smooth with no traces of plicae.
Colour of shell white with collabral, sometime slightly wavy, lines of brown. These
brown lines are irregularly interrupted just abapical of the suture on the spire whorls till
about half way the last whorl. Four more such broad spiral white lines are visible on the
last whorl, the three most adapical ones running towards the shoulder knobs, but the idea
of the broad line disappears just after crossing the first knob. The adbasal one runs
towards what is to become the strombid notch, but the white line appearance has faded
before reaching the strombid notch. Towards the rim of the outer lip, the idea of white
lines reappears, each white line leading towards the tip of a digit. Adapertural side of
outer lip white. Towards the rim of the outer lip, especially the apical side between the
digits and the strombid notch and flange between this notch and anterior canal, of a light
pinkish orange colour. Within the aperture the colouring is very light salmon. Columellar
and parietal callus rather thin, only where spire is embedded the callus is thick, whitish,
abaperturally with the same light pinkish orange, slightly darker at columellar callus. On
parietal area callus very thin, pattern of last whorl shining through.
Operculum and soft parts unknown
Locality data. — Vietnam, Binh Thuan province, approx. 250 km south of Nha Trang,
by local fishermen at 15 – 20 m, summer 2007.
The specimen is kept in the author’s collection reg. No. 6331, and will be deposited in
Nationaal Natuurhistorisch Museum, Leiden, The Netherlands, at some point in the
future.
As names of hybrids are excluded from the International Code of Zoological
Nomenclature (Art. 1.3; see also Art. 17.2 and Art. 23.8 for the availability of Strombus hira-
sei, Lambis arachnoldes, L. wheelwrighti and L. christinae) no name is proposed for the spec-
imen reported herein.
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DISCUSSION
At first glance this specimen could be mistaken for a malformed species of Lambis
Röding, 1798 (type species Strombus lambis Linnaeus, 1758). Such malformations are quite
336 BASTERIA, Vol. 72, No. 4-6, 2008
Lambis lambis supposed hybrid Sinustrombus latissumus
size 92* - 280 mm 184.4 mm 111 - 220 mm
number of digits
on outer lip
6 12 0
Columella smooth smooth smooth
Aperture smooth smooth smooth
Apex pointed pointed pointed
Lateral hump on shoulder
of last whorl,
opposite of aperture
absent or clearly
smaller as next
(adlabial) knob in row
present, slightly larger
as next (adlabial) knob
in row
present, large
knobs on dorsum present,
well developed
present, well devel-
oped
absent
anterior canal elongated short extremely short, merely a
notch
parietal and columellar
callus
abapical of shoulder
broad but relatively
thin, absent on shoul-
der
abapical of shoulder
intermediate and thin,
absent on shoulder
narrow but rather thick
colour pattern outer shell Very variable, cream
with light or dark
brown maculation,
spotted od mottled
with purplish to
blackish wavy narrow
to broad lines
see description herein,
very close to T. latis-
simus
See description of hybrid
specimen discussed herein;
colour lighter on abaper-
tural side of last whorl
colour pattern aperture Cream, tan, some-
times pinkish to
orange rose, towards
rim of outer lip often
light purplish
White, peach/salmon
towards rim of outer
lip
White, peach/salmon
towards rim of outer lip
colour pattern columellar
and parietal callus
Cream, tan, or light
purplish
White, peach/salmon
towards rim of outer
lip, not as dark as in
T. latissimus
White, peach/salmon
towards rim of outer lip
*The measurement of 92 mm corresponds with typical L. Lambis. Extreme malformed dwarfs, measuring
to as little as 45 mm of L. lambis have been named L. adamii Bozzetti & Cossignani, 2003.
Table 2. Comparison of Lambis lambis (Linnaeus, 1758), Sinustrombus latissimus (Linnaeus, 1758) and the
supposed hybrid specimen. Characters of L. lambis and S. latissimus based on literature records and personal
observations.
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common in Lambis spp. (e.g. Walls, 1980: 62, top figs; De Turck et al., 1999: pl. 14, fig. 2, pl.
25 fig. 2, pls. 34, 35; Thach, 2007: pls 82 – 86).
However, in Lambis spp. the digits grow at approximately the same speed and once
their full length is reached, the rims of these digits curl inwards, forming a conical tube,
which is subsequently filled with nacreous material, thus forming a solid digit. This
process is going on simultaneously in all digits, i.e. all digits are in the same growth phase.
An exception to this is Lambis violacea (Swainson, 1821) and, to a lesser extend, L. digitata
(Perry, 1811), where the bifid first digit is lobed in L. violacea and slightly open in L. digi-
tata in adult specimens. Within the specimen here discussed the most adapical digits are
not or barely starting to form the conical tube, while the lateral, most abapical digits are
already completely formed, or even closed. Moreover, these lateral digits are extremely
short, not characteristic of any species of Lambis. The anterior canal within species of
Lambis (with the exception of Harpago Mörch, 1852 (type species Lambis harpago Röding,
1798 [= Strombus chiragra Linnaeus, 1758]), which is, based on morphological grounds,
considered here as a genus rather then a subgenus of Lambis) is very much elongated. This
is not the case in this specimen.
These overall differences with Lambis spp. strongly suggest that this specimen is not
a Lambis, but of a hybrid origin, suggesting that one of the parental species is a Lambis.
The overall habitus with the large and more robust shape of the specimen suggest
that the other parental species should be allocated in what was until recently named
Tricornis Jousseaume, 1886 (type species Strombus tricornis Lightfoot, 1786), Tricornis used
here in the restricted sense, i.e. only applicable to Indo-Pacific species, see Kronenberg &
Vermeij (2002) and Kronenberg & Lee (2007).
As this specimen was found off the Vietnamese coast, I assume that both parental
species live off the Vietnamese coast. This would eliminate L. violacea; L. digitata; and L.
truncata truncata ([Lightfoot], 1786) as possible parental species, as these species live in the
Indian Ocean (Abbott, 1961; Walls, 1980; Kronenberg & Berkhout, 1984; De Turck et al.,
1999) as well as L. robusta (Swainson, 1821) restricted to the Society Islands and Tuamotu
Archipelago. It would also eliminate T. tricornis (Lightfoot, 1786) and T. oldi (Emerson,
1965) as both these species are restricted to the Red Sea and adjacent part of the Indian
Ocean, resp. Oman and Somali coasts (Emerson, 1965; Walls, 1980; Kronenberg &
Berkhout, 1984; De Turck et al., 1999) as well as Sinustrombus. taurus (Reeve, 1857), which
is restricted to the Marshall islands and the Marianas (Abbott, 1960; Walls, 1980;
Kronenberg & Berkhout, 1984; De Turck et al., 1999).
As stated earlier (Kronenberg, 1993) a hybrid specimen would express characters that
are in between both supposed parental species, or a mixture of characters of both parental
species. That is, characters are expressed in a less conspicuous way, but present, for
instance in presence of sculptural elements or colouration of the shell. Based on this
assumption, the specimen reported herein is considered a hybrid of Lambis lambis
(Linnaeus, 1758) × Sinustrombus latissimus (Linnaeus, 1758). For characters of these species
and the supposed hybrid, see Table 2.
The following species of Lambis are reported from the Vietnamese coasts: Lambis cro-
cata crocata (Link, 1807); L. lambis; L. millepeda (Linnaeus, 1758); L. scorpius scorpius
(Linnaeus, 1758); and L. truncata sebae (Kiener, 1843); (Abbott, 1961; Walls, 1980;
Kronenberg & Berkhout, 1984; De Turck et al., 1999).
More recently, both L. crocata pilsbryi Abbott, 1961 (Thach, 2005: 55, pl. 15 fig. 1; 2007:
pl. 82) and L. s. indomaris Abbott, 1961 (Thach, 2007: 65, pl. 15, fig. 260) have also been
reported from off Vietnam.
As there is a complete absence of plicae on the adcolumellar side of the outer lip as
well as on the columella itself,
L. scorpius scorpius (Linnaeus, 1758); L. s. indomaris Abbott,
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1961; and L. millepeda (Linnaeus, 1758) (see Abbott, 1961; Walls, 1980; Kronenberg &
Berkhout, 1984; De Turck et al., 1999) are rejected as possible parental species. These
species also have a vividly coloured aperture, a character they share with L. crocata croca-
ta and L. c. pilsbryi (see Abbott, 1961; Walls, 1980; Kronenberg & Berkhout, 1984; De Turck
et al., 1999; Thach 2005; 2007). For these reasons these species are also rejected as a poten-
tial parental species. Lambis truncata sebae might be taken into consideration, but the apex
of the supposed hybrid discussed herein shows no sign at all of truncation of the spire.
Also, the shoulder knobs on the last whorl in L. t. sebae are very poorly developed. The
size of the shoulder knobs on the last whorl in the supposed hybrid are relatively too well
developed in comparison with the shoulder knobs of L. t. sebae, when taking into account
a possible parental Thersistrombus Bandel, 2008 species also.
Sinustrombus latissimus (Linnaeus, 1758); S. sinuatus (Lightfoot, 1786) and
Thersistrombus thersites (Swainson, 1823) live off the Vietnamese coast (Thach, 2005).
Thersistrombus thersites has a relatively slender spire, an outer wing that is less expanded
lateral in comparison with S. sinuatus and S. latissimus, and the adapical part of the outer
lip stays well below the apex. Sinustrombus sinuatus has a violet to dark purple colour
deep within the aperture.
What remains is the possibility of a hybrid of L. lambis (Linnaeus, 1758) × S. latissimus.
Both these species live off the Vietnamese coast (Thach, 2005) and indeed, this specimen
reported herein shows characters that are intermediate between these two species, or
characters of one of the parental species, more or less strongly expressed (see also table 2).
The more lobe-like character of the first outer lip projections and the subsequent more
open digits in clockwise direction is reminiscent of Lambis violacea.
As with all supposed hybrids within Strombidae (see table 1) reported hitherto, the
animal of the specimen described herein is unknown. Recently an animal of a supposed
hybrid between two species of Lambis has become available for study. The results of this
examination of both shell and soft parts will be published elsewhere (Simone et al. in
prep.). From this specimen a tissue sample for DNA sequencing is also available. Results
of this sequencing will also be published elsewhere.
Especially since the last few decades the number of supposed hybrids within the
Strombidae, both in supposed combinations as well as in absolute numbers, has increased
a lot. There are a few possible explanations for this phenomenon.
First; these hybrids have always been around, but never paid attention to, as large
strombs were mostly used as a source of food for people on the Philippines andother
countries and islands in the Indo-Pacific. The shells had no value at all, and have always
been discarded. Which species taste good and which ones taste bad is of course known.
So, the species that taste better, e.g. Lambis lambis, are widely collected while other species
hardly. With increase of collecting effort on shells for the commercial market, Philippine
collectors are more aware of the value of shells for this market and these fishermen sell
specimens to local shell dealers. In that respect it is indeed remarkable that most hyubrids
are reported from Philippine waters (Kronenberg, 2008) and, to a lesser extend,
Vietnamese waters (Thach, 2007). An exception seems to be the hybrid L. millepeda × L.
trunctata sebae, which is reported from Tsoi Island, Papua New Guinea (Collins, 1980) and
is also known from at least two specimens collected off Pulau Buton, SE Sulawesi,
Indonesia (Bunjamin Dharma, pers. comm. 19 August 2008).
Second; as a result of over collecting, both for food and the commercial shell market,
the parental species of these large strombs are getting more and more scarce. This has
been observed by Mr. Guido T. Poppe (pers. comm. March 2008) for e.g. L. lambis. During
mating season adults find it harder to find a mate of the same species, and, sometimes suc-
cessfully interbreed with other species.
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Third; these viable hybrids may interbreed with (one of the) parental species, as could
be possible in the case of L. millepeda × L. truncata sebae, or without much success as in
those cases where only one or a few hybrids are known. We cannot rule out the possibil-
ity that these hybrids out compete (one of the) parental species.
There is, however, insufficient data to support any of these explanations.
Remarks on the splitting of Tricornis Jousseaume, 1886
Recently, both Bandel (2007) and Dekkers (2008) split up the genus Tricornis in the
restricted sense as used by Kronenberg & Vermeij (2002) and Kronenberg & Lee (2007).
Four names for genus level taxa have become available. The names by Bandel have been
introduced as subgenera of Strombus, Dekkers’ taxon as a full genus.
1. Thersistrombus Bandel, 2007: 146-147. TS Strombus thersites Swainson, 1823.
2. Sinustrombus Bandel, 2007: 155. TS Strombus taurus Reeve, 1857. Another species
included by Bandel (2007: 155) is Strombus oldi Emerson, 1965. Although not explicitely
mentioned in the text, S. sinuatus [Lightfoot], 1786 is also allocated by Bandel to this taxon
as can be concluded from the caption of his text fig. 21b.
3. Latissistrombus Bandel, 2007: 155-156. TS Strombus latissimus Linnaeus, 1758.
Although not explicitely stated, Strombus sublatissimus d’Orbigny, 1852 from the
Oligocene of the Western Tethys might belong to this group according to Bandel (2007:
156).
4. Solidistrombus Dekkers, 2008: 44. TS Strombus sinuatus [Lightfoot], 1786. In the orig-
inal description erroneously the authors name and year appear between brackets. Other
species included (Dekkers, 2008: 46) are S. latissimus; S. taurus; and S. thersitus [sic]. The
names of these species appear already as Solidistrombus spp. with the author’s names and
dates between brackets.
So, we have four genus level taxa, with four different type species for five species.
These taxa partly overlap one another, and therefore it is important to establish the dates
when these papers were published.
In an email sent on April 1
st
by Bandel to the present author, it was stated: “I finished
my Opus on the Strombimorpha …”, without further referring to a date of publication.
There is no date of publication printed on the paper by Bandel, but Dr. Olaf Elicki, editor
of Freiberger Forschungshefte, informed me (email 24 April 2008) that is was published in
December 2007. As no exact date could be specified, the publication of Bandel’s paper is
31 December 2007 following ICZN Article 21.3.1.
The cover of “De Kreukel” that carries the paper by Dekkers is dated “maart-april
2008”. Mr. Cor Karnekamp had copies of this issue available on April 19
th
, and when
asked he stated that the issue had come from the printers’ the previous day, i.e. April 18
th
.
Therefore, if synonymous, the names introduced by Bandel have priority over
Solidistrombus Dekkers, 2008.
Species assigned to Lentigo Jousseaume, 1886 (TS Strombus lentiginosus Linnaeus,
1758); Euprotomus Gill, 1870 (TS Strombus aurisdianae Linnaeus, 1758); and Tricornis sensu
Kronenberg & Vermeij (2002) and Kronenberg & Lee (2007) have the rim of the outer lip
that runs more or less parallel to the shell axis, when reaching adulthood, bent into adcol-
umellar direction in various degrees, sometimes barely detectable, and subsequently the
outer lip is thickened and the rim of the outer lip more or less extensively glazed. In
Lentigo the bending is only slight. In Lentigo lentiginosus (Linnaeus, 1758) this glazing is
rather extensive, but in L. pipus (Röding, 1798), the only other recent species of Lentigo, this
glazing is very narrow (pers.obs.). In all Euprotomus spp. the bending is slight and the
glazing is extensive. In Tricornis
the bending is very slight in T. oldi and slight in T. tricor-
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nis, but in T. sinuatus; T. taurus and T. latissimus the bending is very conspicuous (fig. 5), to
a degree where a cavity is formed that is subsequently filled with inner shell material
prior to the subsequent glazing of the outer lip.
The difference between a rounded adapical part of the outer lip of the shell as
observed in Tricornis latissimus and lobes as observed in T. sinuatus and digits as in T. tau-
rus is nothing but a slight difference in the presence or growth of lobes of the rim of the
mantle demonstrated in this hybrid and also in Lambis violacea (see above). Therefore I
consider the names Sinustrombus Bandel, 2007 and Latissistrombus Bandel, 2007 to be syn-
onymous. Acting as first reviser (see ICZN Article 24.2) I give precedence to the name
Sinustrombus. Solidistrombus Dekkers, 2008 is a junior synonym.
From a morphological point of view this name could be used to denote a group of
species with a derived character of the rim of the outer lip. Therefore I consider
Sinustrombus a genus within a clade that also encompasses Tricornis; Lambis; and Harpago,
and not a subgenus of Strombus as indicated by Bandel (2007: 142). The large species
reported by Ladd (1972: 58, pl. 17, figs 1, 2) as Strombus (Tricornis) sp. A, might also belong
to this genus.
Kronenberg & Vermeij (2002) pointed out that projections on the outer lip arose mul-
tiple times independently in stromboidean clades. Whether these digits arose independ-
ently in Sinustrombus taurus in relation to Lambis spp. is not very likely. In the consensus
tree as presented by Latiolais et al. (2006) S. sinuatus and S. taurus (both allocated to
Tricornis) plot out as sister to Lambis. Moreover, the case of hybridisation as reported here-
in shows a close genetic connection between at least one species of Sinustrombus and one
species of Lambis. It seems that within Sinustrombus there is a tendency to form extensions
on the rim of the outer lip, a tendency that is pushed up further in Lambis spp.
The extensive bending of the rim of the outer lip is however not observed in
Thersistrombus thersites. Bandel (2007: 147) mentioned the resemblance of the spire and
form of the outer lip of T. thersites with those of Persististrombus granulatus (Swainson,
1822). Although at first glance this may seem far-fetched, but going back into the fossil
record, there may indeed be a connection with Persististrombus. Species allocated to
Persististrombus are known from the Chattian (late Oligocene) and Aquitanian (early
Miocene) of Oman, respectively P. bernielandaui (Harzhauser, 2007) and P. gijskronenbergi
(Harzhauser, 2007). Another species allocated to Persististrombus from the Aquitanian of
Tanzania is currently under description (Harzhauser, in press).
Harzhauser et al. (2007) mentioned only Strombus preoccupatus Finlay, 1927 as a mem-
ber of this radiation stating that S. preoccupatus was the last surviving species of that radi-
ation. Without critically reviewing the following nominal taxa, as this is beyond the scope
of this paper, Strombus sedanensis
Martin, 1899 from the early Miocene of Java and Pakistan
Abbott (1960: 102) and the Langhian and Serravilian, middle Miocene, of Borneo (Raven,
2002: 13); S. preoccupatus from the early and late Miocene of Java and Borneo; S. daviesi
Dey, 1962 from the Miocene Quilon beds of Kerala, SW India; and both S. quilonensis Dey,
1962, and S. cossmanni Dey, 1962, also from the Miocene Quilon beds of Kerala, SW India;
are tentatively considered part of the Indo Pacific radiation of Persististrombus by the pres-
ent author. Whether or not the name Persististrombus should be used for these species is
not yet resolved.
Strombus preoccupatus was allocated to Lentigo by Abbott (1960: 123), mentioning a
similarity with Strombus granulatus. Strombus sedanensis was allocated to Dolomena Wenz,
1940, TS Strombus pulchellus Reeve, 1851 [Dolomena Iredale, 1931 is a nomen nudum, see
Kronenberg & Dharma, (2005)], by Abbott (1960: 102) as being a fossil relative of
“Strombus” marginatus.
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Subsequently, Abbott (1965) allocated S. preoccupatus; S. daviesi (as S. sedanensis
daviesi); S. quilonensis (as S. preoccupatus quilonensis) and S. cossmanni [regarded by Abbott
(1965: 402) as a juvenile of S. p. quilonensis] to Dolomena. The allocation of these species to
either Lentigo or Dolomena by Abbott is rejected here.
The large Strombus maximus Martin 1883, allocated to Tricornis by Abbott (1960: 56)
may also be part of this radiation, but being ancestral to the Recent Thersistrombus thersites
is not likely in the present author’s opinion, judging by the shape of the outer lip in api-
cal view.
Thersistrombus is provisionally accepted as a genus derived from an ancestor within
the Indo-Pacific Persististrombus radiation, and not a subgenus of Strombus as indicated by
Bandel (2007: 142). The specimen reported by Ladd (1972: 58, pl. 15 fig. 7) as Strombus
(Tricornis) aff. S. thersites Swainson from the Futuna Limestone, “lower Miocene” of Fiji is
too poorly preserved for a proper identification, but is definitely not Thersistrombus ther-
sites.
As stated before (Kronenberg & Lee, 2007: 262) the overriding problem of conver-
gence in the Strombidae impedes a morphological analysis of evolutionary relationships.
Besides the example already mentioned by Kronenberg & Lee (2007) there is a striking
resemblance between Lobatus goliath (Schröter, 1805) from Brazil and the Indo-Pacific
Sinustrombus latissimus. Also, the non-dilating, unglazed, sharp-rimmed outer lip of
Conomurex P.Fisher, 1884 and Margistrombus Bandel, 2007 (synonym: Neodilatilabrum
Dekkers, 2008) may very well be due to convergence rather then close phylogenetic rela-
tionships.
A re-appraisal combining morphological, anatomical, and molecular data of all
species of Tricornis (in the broad sense, i.e. including Sinustrombus and Thersistrombus) and
Lambis (in the broad sense, i.e. including Harpago) is badly needed.
ACKNOWLEDGEMENTS
First and fore all many thanks are due to Dr Nguyen Ngoc Thach for making the spec-
imen discussed herein available for study. Mr Jean-Pierre Barbier, Cebu, Mactan,
Philippines provided important information on his collection of hybrid Strombidae. Mr
Barbier; Mr Jeroen Goud, Nationaal Natuurhistorisch Museum, Leiden, The Netherlands;
Mr Vigilio Liverani, Faenza, Italy; and Mr Joop Wiersma, Kerkrade, The Netherlands
shared their opinions on this remarkable specimen. Jeroen Goud also made the photo-
graphs. Thanks are also due to Mr Fred Schroeder, Guam for making his specimen of the
Sinustrombus sinuatus × S. taurus hybrid available for photograpy and Mr Bob Abela,
Guam, for mediation and sending images of this specimen. Thanks are also due to Mr
Bunjamin Djarma, Djakarta, Indonesia for sending images of the specimens of L. millepe-
da × L. trunctata sebae collected off Buton, Indonesia and Mr Sofjan Effendy, also Djakarta,
Indonesia, for making the specimens available for photography. Mr Cor Karnekamp,
Diemen, The Netherlands presented a copy of an issue of “De Kreukel” containing the
Dekkers paper and provided important information on the date of publication. Dr Olaf
Elicki, editor of Freiberger Forschungsheftel, provided information on the date of publi-
cation of the paper by Klaus Bandel. Dr Geerat J. Vermeij, University of California at
Davis, reviewed the manuscript and made useful comments.
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