Janthina Röding, 1798

Beu, Alan G., 2017, Evolution of Janthina and Recluzia (Mollusca: Gastropoda: Epitoniidae), Records of the Australian Museum (Rec. Aust. Mus.) 69 (3), pp. 119-222 : 161-165

Janthina Röding, 1798

Janthina Röding, 1798: 75 . Type species (by tautonymy): Helix janthina Linnaeus, 1758 ( H. janthina cited in synonymy of Janthina violacea Röding, 1798 ); Recent, cosmopolitan.

Ianthina Lamarck, 1801: 427 . Incorrect subsequent spelling of Janthina Röding, 1798 (many later authors used this incorrect spelling).

Janthinus Montfort, 1810: 214 . Incorrect subsequent spelling of Janthina Röding, 1798 .

Zanthina Fischer von Waldheim, 1823: 236 . Incorrect subsequent spelling of Janthina Röding, 1798 .

Ametistina Schinz, 1825a: 586 (suppressed under ICZN Opinion 989, 1972).

Hyanthina Porro, 1841: 87 . Incorrect subsequent spelling of Janthina Röding, 1798 .

Achates Gistel, 1848: 169 (unnecessary substitute name for Janthina ); Mörch, 1860: 277. Type species (automatically that of the substituted name): Janthina violacea Röding, 1798 (= Helix janthina Linnaeus, 1758 ).

Ametistina H.Adams &A.Adams, 1854: 86 (nomen nudum).

Amethystina Chenu, 1859: 118 (nomen nudum).

Iodes Mörch, 1860: 273 . Type species (by subsequent designation, Tryon, 1887: 34): Iodes britannica “Leach ” Forbes & Hanley, 1852 (= Helix janthina Linnaeus, 1758 ).

Iodina Mörch, 1860: 282 . Type species (by subsequent designation, Tryon, 1887: 34): Janthina exigua Lamarck, 1816 ; Recent, cosmopolitan.

Amethistina Mörch, 1860: 282 ; section of nominotypical subgenus of Janthina ; attributed by Mörch to “Schintz”. Type species (by subsequent designation, Tryon 1887: 34): Janthina pallida Thomson, 1840 ; Recent, cosmopolitan.

Hartungia Bronn, 1861: 110 . Type species (by monotypy; combined description of a new genus and species): Hartungia typica Bronn, 1861 ; early Pliocene (Zanclean), Santa Maria Island, Azores; late Messinian to early Piacenzian, cosmopolitan.

Jantina Weinkauff, 1873: 66 . Incorrect subsequent spelling of Janthina Röding, 1798 .

Jodes Marschall, 1873: 122. Incorrect subsequent spelling of Iodes Mörch [ex Leach ms], 1860.

Jodina Marschall, 1873: 122 . Incorrect subsequent spelling of Iodina Mörch, 1860 .

Eligmope Dennant, 1889: 48 (nomen nudum).

Heligmope Tate, 1893: 328 . Type species (by monotypy): Heligmope dennanti Tate, 1893 (= Hartungia typica Bronn, 1861 ).

Amethystina Pallary, 1920: 56 . Incorrect subsequent spelling of Amethistina Mörch, 1860 .

Violetta Iredale, 1929: 279 . Type species (by original designation): Janthina globosa Swainson, 1822 ; Pliocene–Recent, cosmopolitan.

Parajanthina Tomida & Itoigawa, 1982: 60 . Type species (by original designation): Parajanthina japonica Tomida & Itoigawa, 1982 (= Hartungia dennanti chavani Ludbrook, 1978 ); late Pliocene–early Pleistocene, cosmopolitan.

Kaneconcha Kaim, Tucholke & Warén, 2012: 427 . Type species (by original designation): Kaneconcha knorri Kaim, Tucholke & Warén, 2012 (= Hartungia dennanti chavani Ludbrook, 1978 ).

Remarks. The name Iodes was first introduced as a nomen nudum by Gray (ex Leach ms) (1847a: 269) (Oct) and Gray (1847b: 148) (Nov) in the synonymy of Janthina . Its original rank was a subgenus of Janthina ; the name was attributed by Mörch (1860) and Tryon (1887) to Leach. The name Janthina britannica was first introduced in synonymy (of Janthina communis Lamarck, 1822 , i.e., J. janthina ), but was made available under ICZN Art. 11.6.1 by its use as a valid name, e.g., by Mörch (1860: 273). Tryon (1887: 34) included the single species “ Ianthina britannica Leach ” in “ Iodes (Leach) Gray, 1847 ”, but it is not clear that this was intended to be a type species designation, as he stated that “The following sections of Mörch have very slight value”, and that he was merely assigning a single species to each section. Nevertheless, it is the one published type species designation the writer is aware of. The same type species question applies also to Iodina Mörch, 1860 and Amethistina Mörch, 1860 . Cossmann (1925: 158) also designated Janthina exigua as the type species of Iodina , and on the same page also designated J. pallida as the type species of “ Amethistina Schinz 1825 (fide Moerch, 1860)” and so is taken here to have designated J. pallida as the type species of Amethistina Mörch, 1860 .

Bronn (1861) compared his species Hartungia typica with Janthina species, and although he did not use a family-group heading, he expressly included it in Janthinidae . The Atlantic fossil species revised here were also referred to Janthina by Mayer (1864a, b). Finlay (1931) was the first to realize that Turbo postulatus Bartrum, 1919 belongs in Heligmope Tate, 1893 and that Heligmope is a genus of Janthinidae . Recognition that Hartungia Bronn, 1861 is an earlier name for Heligmope Tate, 1893 and that Hartungia belongs in the Janthinidae must be credited to Chavan (1951). The writer was informed by C. A. Fleming that Chavan’s (1951) brief paper inspired Fleming’s (1953a) research. Chavan (1951) regarded Hartungia as a subgenus of Acrybia H. Adams & A. Adams, 1853 . Chavan thought Acrybia was the valid synonym of Bulbus Brown, 1839 , because the name Bulbus had been used earlier by Humphrey (1797). Cossmann (1925: 159) had come to the same conclusion and ranked Heligmope Tate, 1893 as a subgenus of Acrybia , so Chavan (1951) was following Cossmann’s classification, although Cossmann (1925) did not mention the name Hartungia . However, Humphrey’s (1797) work is non-binominal and all names introduced in it are unavailable (ICZN Opinion 51, 1912), which leaves Bulbus Brown, 1839 as an available name. Bulbus is a genus of Naticidae , mainly distributed in the boreal region. Dell (1990: 153) discussed the genus Bulbus , treated Acrybia as a junior synonym, and recorded three Antarctic species. Fleming’s (1953a) brief list of species related to Hartungia typica and suggestion that they provided a novel means of Pliocene correlation provided the initial impetus for the present work.

A significant difficulty with Laursen’s (1953) otherwise excellent monograph of Janthina is his failure to identify type specimens. Laursen illustrated Linnaeus’s (1758) syntypes of Helix janthina in Uppsala, Sweden, and in the Linnean Society’s collection in London, but although he recognized that two species are represented he did not designate an unequivocal lectotype. Laursen also did not mention any type material of any other species names. Therefore, a major emphasis of the present work has been to stabilize the nomenclature by identifying all possible available names with particular species by finding or designating type specimens, particularly for the early-proposed names that could be referred to any of several species. Twenty two neotypes and six lectotypes are proposed in this report to identify names unambiguously, to avoid future confusion about which names apply to which species. An Appendix (p. 208) lists the new type designations in the present work. As all revised species are at present or are assumed to have been formerly cosmopolitan neustonic species in temperate and tropical seas, the usual requirement that neotypes should come from as near as possible to the original type locality is considered to be unimportant in this case. Also, some type specimens have debated localities (e.g., Recluzia rollandiana Petit de la Saussaye, 1853 —from western Mexico or from New Caledonia?). Designating a suitable neotype of the appropriate species was deemed more critical than matching the original type locality for cosmopolitan Janthina and Recluzia species.

The teleoconch of Janthina is characterized by its violet colour, its more-or-less equidimensional heliciform shape, its fine axial teleoconch sculpture (present in only some of the living species, but in all extinct species) resembling that of finely sculptured Epitonium species, and its sinus in the outer lip. Differences between Janthina , Recluzia and benthic Epitoniidae are listed in Table 1 . In the fossil species J. typica , J. krejcii and J. chavani the sinus is small and located at the base of the outer lip, semicircular in most specimens, although a little wider in some specimens of J. chavani . It generates a spiral fold parallel to the inner lip, wider than the other spiral folds on the rest of the surface. In contrast, in most living species the sinus is V-shaped and occupies the entire width of the outer lip, with its apex at the centre of the lip, and does not generate any swelling of the shell surface. The sinus is shallow in Janthina janthina and more obvious in the basal limb of the lip than adapically, and is very shallow in J. pallida , but it is deeper, wider and more prominent in the other living species, particularly in J. exigua and J. umbilicata . Photographs of living specimens ( Figs 4B–C , 5A, E ) reveal that the (main?) function of the sinus is to accommodate the head and snout as they protrude permanently from the shell. In a species that cannot retract its head at any time, as it must protrude (with the mesopodium) to retain the bubble float, the sinus accommodates the protruding head. However, the much narrower and more basal lip sinus of the extinct species J. typica , J. krejcii and J. chavani suggests that the sinus originally had a different function, possibly to allow the extrusion of egg capsules. The axial sculpture and the closely similar protoconch are characters in common with benthic Epitoniidae . Janthina essentially contains short, wide, violet, neustonic species of Epitonium that have undergone mutations of the pedal mucus gland and propodium enabling them to form mucus bubbles, attach them to each other to form a float, lay relatively large egg capsules attached to the float rather than chalazae-linked small capsules, and all the other necessities of the neustonic habit. The minor shape and sculptural characters used by, e.g., Mörch (1860) and Iredale (1929) to distinguish genera or subgenera within Janthina are regarded here as merely species characters. The groups segregated by Mörch (1860) were treated as sections of Janthina by Thiele (1929: 225), but have been used by few other authors. Whether the adult lays egg capsules or broods its eggs in the oviduct also is a developmental difference, of no phylogenetic significance ( Bouchet, 1990).

Included species. Species included here in Janthina are listed and revised in their order of appearance in the stratigraphical record.

1 Janthina typica ( Bronn, 1861) (= Janthina hartungi Mayer, 1864 , Heligmope dennanti Tate, 1893 , Turbo postulatus Bartrum, 1919 , Acrybia (Hartungia) chouberti Chavan, 1951 , Hartungia elegans Tomida & Itoigawa, 2001 , Eunaticina abyssalis Simone, 2014 ), late Miocene‒early late Pliocene (Messinian‒early Piacenzian), Azores, Madeira, Selvagem Is., SW Atlantic, Morocco, New Zealand, southern Australia, Japan; presumably formerly cosmopolitan.

2 Janthina krejcii sp. nov., Pliocene (Zanclean), Santa Maria I., Azores; presumably formerly cosmopolitan.

3 Janthina chavani ( Ludbrook, 1978) (= Parajanthina japonica Tomida & Itoigawa, 1982 , Kaneconcha knorri Kaim, Tucholke & Warén, 2012 ), late Pliocene–early Pleistocene (late Piacenzian–Calabrian), southern Australia, New Zealand, Japan, mid-Atlantic ridge; presumably formerly cosmopolitan.

4 Janthina globosa (Swainson, Jan 1822) (= J. prolongata Blainville, Aug 1822 ), Piacenzian/Gelasian–present day, cosmopolitan in warm seas; Piacenzian–Gelasian fossils from Jamaica and Luzon, Philippines.

5 Janthina janthina ( Linnaeus, 1758) (30 synonyms), one Holocene fossil in New Zealand, many reported from core tops in the Mediterranean Sea and the Cariaco Basin, Caribbean; living, cosmopolitan in warm seas.

6 Janthina exigua Lamarck, 1816 , living only, cosmopolitan in warm seas.

7 Janthina pallida Thomson, 1840 , living only, almost cosmopolitan in warm seas; not recorded from New Zealand or eastern Australia.

8 Janthina umbilicata d’Orbigny, 1841 , living only, cosmopolitan in warm seas.

Taxa not included. The following taxa have been included in Janthinidae by earlier authors, but are excluded here from Epitonioidea:

1 Röding (1798: 75–76) included six species in Janthina , first section, “Elevata”, and a further nine species and four varieties in a second section, “Depressiuscula”. The second section obviously has nothing to do with Janthina as used now, as most names refer to Gmelin (i.e., mostly Linnaeus) Helix species ( H. pomatia , with two varieties; H. scalaris , H. ligata , H. jamaicensis , H. picta ) and three are nomina nuda. Four of the six names in section Elevata also are nomina nuda, none of which has been referred to again to the writer’s knowledge ( J. singularis , J. turbinoidea , J. limbata , J. pellucida ). The fifth name, J. cytherea , refers to Chemnitz (1786: pl. 123, fig. 1063), a basal view of a small blue-grey shell on a plate showing terrestrial snails, so this is an available but probably unidentifiable name.

2 Janthina alba Anton, 1838 : Anton (1838: 50) noted that the specimen he described as Janthina alba might really be a young specimen of Helix pisana . Dr K. Schniebs (Senckenberg Naturhistorische Sammlung Dresden, pers. comm. 23 Feb 2016) stated that Anton’s own copy of his catalogue has a hand-written note by Anton: “It is Helix pisana Mllr. juv.”, so this name is a synonym of Theba pisana (Müller, 1774) , Helicidae . A type specimen is not present in Dresden.

3 Kaiparathina Laws, 1941 : Laws (1941) presumably composed this generic name because he thought the shallow sinus in the outer lip of the early Miocene type species indicated that it is related to Janthina ( K. praecellens Laws, 1941 , Pakaurangi Point, Kaipara Harbour, New Zealand; Otaian New Zealand Stage, 21.7–18.7 Ma, late Aquitanian–early Burdigalian). He did not refer the genus to a family, apparently deliberately, although he compared it with some of the characters of Heligmope (i.e., Hartungia ; synonymized here with Janthina ). This small (height 3.2 mm), thick, aragonitic shell with a nacreous inner layer was referred to the Trochidae by Beu (1973) because a nacreous inner shell layer is plesiomorphic for Vetigastropoda, particularly Trochoidea and Turbinoidea ( Williams et al., 2010). This position was confirmed by Marshall (1993) when he described five living Southwest Pacific species, recorded fossils as old as early Eocene, and referred the genus to Margaritinae Kaiparathini. Williams (2012: 589) placed Kaiparathina in family Trochidae , subfamily Kaiparathininae Marshall, 1993 .

4 Edithais pehuensis ( Marwick, 1926: 319, pl. 73, figs 6, 8), late Miocene (Tongaporutuan New Zealand Stage, Tortonian); referred to Lippistes Montfort, 1810 by Marwick (1926), to Heligmope by Finlay (1931: 5) following a suggestion by J. Marwick, and to Hartungia by Fleming (1953a; 1966: 49, pl. 90, figs 948, 950), Tomida & Nakamura (1981) and Tomida & Kitao (2002). However, it was referred to Concholepas Lamarck, 1801 by Beu (1970) and to the cosmopolitan muricid genus Edithais Vermeij, 1998 by Vermeij (1998). This unusual shell with an isostrophic spire and regular, low, wide spiral cords has a general resemblance to Janthina typica , but the enlarged spiral ridge bordering the wide umbilical hollow fades out before the aperture, i.e., it is not generated by a sinus in the lip, the axial ridges are low, wide and widely spaced, and the spire is below the top of the aperture. The similarity is increased by its thin, dark brown, calcitic outer layer over a thicker aragonitic inner layer, but this is seen also in many other muricids. Holotype (still the only known specimen): GNS TM4494, mid-Tongaporutuan New Zealand Stage (mid-Tortonian, late Miocene, c. 9 Ma), Okoke Road, 1.2 km west of Pehu trig. station, Waitara district, North Taranaki. Edithais , Family Muricidae .

5 Janthina cimbrica Sorgenfrei (1958: 176 , pl. 32, fig. 110), Arnum Formation, Denmark (Miocene), from a depth of 55 m in a well at Glejbjerg. This minute (H 1.68, D 1.37 mm) evenly inflated shell with sculpture of microscopic cancellate lirae does not belong in Epitoniidae . It is a larval shell, type species of Mioseguenzia Nordsieck (1973) (nomen nudum), recognized as cypraeacean by Quinn (1983: 727, 744) following comments by P. Bouchet, and referred to Cypraea by Janssen (1984: 195). Janssen (1984: pl. 8, figs 7–8) illustrated very similar protoconchs of Cypraeidae from Winterswijk-Miste, the Netherlands (middle Miocene). Cypraea (sensu lato), Family Cypraeidae .

6 Janthina primigenia Seguenza (1867: 18 , figs 1a–3) and J. delicata ( Philippi, 1844) var. subangulosa Seguenza (1867: 19) , Pliocene, Messina, Sicily. In a review of Seguenza’s types remaining in the University of Florence, Bertolaso and Palazzi (2000: 34, figs 54–55) illustrated type material of Janthina delicata var. subangulosa , and concluded that it is a synonym of Torellia delicata ( Philippi, 1844) . Evidently no type material remains of J. primigenia ; many of Seguenza’s types were destroyed in the Messina earthquake. The small size (D c. 8 mm), low, wide shape, numerous narrow whorls and simple, close, fine spiral sculpture revealed in Seguenza’s illustrations show that these names do not refer to species of Janthina ; both are assumed to refer to Torellia delicata ( Philippi, 1844) . Torellia , Family Capulidae .

7 Shuto (1969: 98, pl. 6, figs 15–18) recorded Janthina janthina from latest Miocene rocks of Panay Island, Philippine Islands. His illustrations show a small, smooth, low-spired shell with a narrowly open umbilicus, evenly inflated whorls without the peripheral angulation of J. janthina , a straight acline outer lip, and a large (width 3.25 mm) low protoconch of less than one whorl, so it is clearly a direct-developing species; apparently based on a juvenile specimen of a terrestrial pulmonate snail.

8 Sherborn (1922–1933) listed four further names in Janthina based on Palaeozoic fossils. Mörch (1860: 272) also listed several Palaeozoic genera that he thought might be related to living pelagic gastropods, including pteropods and heteropods: Platyschisma , Raphistoma , Scalites , and several species of Murchisonia and Pleurotomaria . This list was repeated by Tryon (1887). In view of suggestions of a poorly known pre-late Miocene fossil record ( Nützel, 1998: 89) it is important to record that all these Palaeozoic fossils are now referred to superfamilies Murchisonioidea or Pleurotomarioidea and have no relationship to Epitonioidea. The species listed by Sherborn are all Carboniferous:

a Janthina glabrata (Phillips) .—McCoy in Griffith (1842: 19); Pleurotomaria glabrata Phillips (1836: 228) , Pleurotomarioidea.

b Janthina helicoides (Phillips) .—McCoy in Griffith (1842: 19); Pleurotomaria helicoides (J. Sowerby) in Phillips (1836: 228); Ampullaria helicoides J. Sowerby (1826: 40) , Pleurotomarioidea.

c Janthina issedon Verneuil in Murchison et al. (1845: 341, pl. 23, figs 5a–b); Scalites issedon (Verneuil) in d’Orbigny (1850: 121); Scalites was referred to Raphistomatidae (Pleurotomarioidea) by Knight et al. (in Moore 1960: 201).

d Janthina ovoidea (Phillips) .—McCoy in Griffith (1842: 19); Pleurotomaria ovoidea Phillips (1836: 228) , Pleurotomarioidea.

Nomina nuda. Several names proposed in Janthina were not accompanied by descriptions or illustrations and remain nomina nuda. They are listed here with comments, and are not included in any of the synonymies below.

1 Janthina subsinuosa Bronn : Bronn (1826: 328) merely listed this name. Presumably based on a Recent Mediterranean species of Janthina , but unrecognisable; not J. exigua , which is listed on the same page.

2 Janthina vulgaris Grant : Grant (1833: 14) recorded large numbers of Janthina “ vulgaris Lam. ” and Velella cast ashore at Whitsand Bay, near Land’s End, Cornwall. No description or reference accompanied the name. Gray later published the name J. vulgaris in several places, but it remained a nomen nudum until validated by Gray (1850: 101), referring to earlier illustrations by Lister, “Forskael”, Cuvier, Lesueur, and Quoy [& Gaimard] as referring to this species. These references demonstrate that Gray (1850) intended to use the name J. communis (= J. janthina ) rather than J. vulgaris ; he used the name J. communis for the same Quoy & Gaimard illustration earlier in the same work ( Gray 1850: 9; referring to Lister, Quoy [& Gaimard, 1833, pl. 29, figs 1–2] and “Forskael”), and there is no voucher material bearing the name Janthina vulgaris in NHMUK.

3 Janthina bifida “Nuttall ”: Jay (1839: 68) listed this name without any indication or description, other than the locality “Wahoo” (Oahu, Hawaii) and it has never been made available.

4 Ianthina rotundata (Leach ms) Dillwyn and Ianthina mediterranea (Jeffreys ms) Dillwyn: Dillwyn (1840: 59) included in a section “Zoological memoranda” the following statement: “1824, July—many thousand shells of Janthina , of which some retained the animals alive, and skeletons of the Medusa Velella and of the Medusa Navicula were thrown on the shores of Oxwich Bay—the weather was remarkably hot at the time. A few of these Janthina , which had before at different times been washed up in the same bay, received from Dr Leach his MS name of J. rotundata ; and Mr Jeffreys informs me, that among the multitude which now covered the shore, he detected a few shells of J. mediterranea mixed with them” [Italics added]. Smart & Cooke (1895: 298) also gave an account of strandings in the Scilly Isles under the name “ Ianthina rotundata Leach ”, presumably referring to J. janthina , although again there is no way of telling which species they intended. They noted: “Occasionally driven on shore from the westward, on the beaches facing south-west. The Scillonians have an idea that they come in at fixed periods of about seven years. The South Wales fishermen about Tenby have the same belief. … Occasionally they have occurred in such numbers that hundreds might have been collected at once”. The main other mention of these nomina nuda the writer is aware of is by Locard (1898: 1), who listed “[ Janthina ] rotundata, Leach, 1840 . In Dillwyn, Contr. Hist. Swans., p. 59” in the synonymy of J. communis . Laursen (1953) also included J. rotundata Dillwyn in the synonymy of J. janthina , but did not mention J. mediterranea . Some later authors have listed J. rotundata Leach as a nomen nudum in the synonymy of J. janthina , but the writer is not aware of any means of determining which species were intended by these names.

5 Iodes angulatus and Iodes norrisii Leach : Gray [ex Leach ms] (1847a: 269) published a list of names of British Mollusca, including the nomina nuda Iodes angulatus and Iodes norrisii . In Gray’s editorial introduction to Leach (1852: x) ( Petit, 2012: 94, note 29), Gray stated that Iodes angulatus Leach is “ Ianthina vulgaris Lam. ” (nomen nudum, presumably intended for J. communis Lamarck , = J. janthina ), but did not identify Iodes norrisii .

6 Janthina striata Montrouzier : Montrouzier (1860: 115) listed this name after his description of J. capreolata ( Montrouzier, 1860: 114, pl. 11, fig. 4) without providing any description or indication for J. striata , and the name has never been made available.

7 Janthina bipartita Tenison Woods : Tenison Woods (1878: 44) included in a list of Tasmanian shells the three names Ianthina exigua Lamarck , Ianthina communis Lamarck , and Ianthina bipartita “Gray ?”. No description, locality or other comments followed the last name, and the writer knows of no other mention of it.

8 Janthina nicobarica “Reeve ”: Laursen (1953: 16) mentioned after the synonymy of J. janthina that specimens in ZMUC are labelled “ Janthina nicobarica Reeve ”. He had also seen the name attributed to Röding. It was also listed by Rosenberg (2017) in the synonymy of J. janthina , attributed to Laursen. However, it was not made available by any authors, and remains a nomen nudum.

Figures

Figure 4 (facing page 129). Living animals in aquaria. (A) Janthina janthina (Linnaeus) (centre) and J. pallida Thomson (left, and part of another float at right) together, showing different bubble sizes in floats, and J. janthina feeding on pink eggs of J. pallida beneath float; collected at Arina Beach, Heraklion, Crete. (B) Janthina janthina, collected on beach in northern New South Wales, Australia, clearly showing forked cephalic tentacles;(C–E) Janthina janthina, all data as for Fig.4A; C, showing forked cephalic tentacles, lack of eyes, and teeth and odontophore protruding from mouth at end of extended snout; D–E, showing extended head and snout, odontophore visible in mouth, and partially expanded right epipodium lying over shell (A, C–E, reproduced with permission of Dimitris Poursanidis, Heraklion, Crete; B, reproduced with permission of Denis Riek, Brunswick Heads, New South Wales). Scale bars 10 mm.

Figure 5. (See facing page 131 for caption).