Beu: Evolution of Janthina and Recluzia 
191 
shaded, darker violet on ventral surface and paler on dorsal 
surface, some with pale zone around centre of base; highly 
variable in all characters. Broods eggs in oviduct, releasing 
rapidly bursting packets of veligers. 
Remarks. The huge number of specimens of Janthina 
janthina in collections all over the world exhibits a wide 
range of variation in both shape and colour. Failure to 
recognize this as the variation of a single species led to 
the recognition of many nominal species by early authors, 
particularly Reeve (1858). Laursen (1953: fig. 15) provided 
a useful figure of specimen outlines (Fig. 33) revealing the 
completely intergrading variation in shape, particularly in 
spire height, anterior columellar shape and the degree of 
angulation at the periphery of the last whorl, demonstrating 
that all these forms are part of the variation of one species. In 
collections the writer has examined, specimens resembling 
Laursen’s (1953: fig. 15) numbers 5-9 are the most common 
shape, and juvenile specimens all resemble Laursen’s 
numbers 10-12; extremely tall-spired forms such as 
Laursen’s numbers 1-2 are rare. Wilson and Wilson (1956) 
& Wilson (1958) also compared the dimensions of a large 
number of stranded southern British specimens graphically, 
again demonstrating their intergradation. Specimens from 
near the southern limit of its range in New Zealand bear 
obvious, fine, close, axial ridgelets similar to those of 
Janthina exigua on the initial 1—1.5 teleoconch whorls, 
whereas the rest of the teleoconch surface is essentially 
smooth, with weak growth lines and many weak, irregular 
spiral threads. Laursen (1953: 18) described this sculpture as 
“The first 1 !4 whorls may have sharp, regular striae, which 
pass into a fainter, irregular striation”, it was illustrated by 
Robertson (1971: pi. 5, fig. 17; 2007a: 8, upper left fig.), and 
this axial sculpture occurs on most specimens throughout 
its range. The remainder of the surface in J. janthina is 
not as smooth and polished as in J. globosa and J. pallida. 
Spiral coiling is rather irregular. A small proportion of 
adult shells also bears low spiral folds and grooves below 
the shoulder angulation, producing sculpture not unlike the 
more prominent and much more consistently present spiral 
folds of J. typica and J. chavani , although the folds are much 
fewer and weaker in J. janthina (Figs 2A, D, 4A, 5A). The 
radular teeth of J. janthina (Laursen 1953: figs 16-18) are 
moderately long and moderately strongly hooked, much 
longer than those of J. pallida , but similar to those of J. 
exigua and J. umbilicata. They vary significantly in length 
within one radula. 
Priolo (1959:185-186) provided a list of numerous usages 
in the literature on Mediterranean molluscs of the name 
Janthina bicolor , which he evidently considered to apply 
to a species distinct from J. janthina. 
Time range. Holocene fossils and living only. 
Janthina exigua Lamarck, 1816 
Figs 2M, O, 34A-C, E-F 
Janthina exigua Lamarck, 1816, “Liste des objets”: 12, pi. 
456, figs 2a-b; Eschscholtz, 1825: column 737; Gray, 
1827: 495; Deshayes, 1843: 5; Gray, 1843: 241; Benson, 
1860: 40; Kuster, 1868: 7, pi. 2, figs 6-7; Monterosato, 
1878: 95; Hutton, 1882: 128, pi. 14, fig. G (radula); 
Hutton, 1904: 80; Moss 1908: 28, pi. 7, fig. 1; Suter, 1913: 
299, pi. 44, fig. 12; Oliver, 1915: 525; Bucknill, 1924: 
50, pi. 19, fig. 4; Finlay, 1928: 246; Powell, 1937: 74, pi. 
10, fig. 30; Mermod, 1953: 201, figs 200.1-2; Pasteur- 
Humbert, 1962: 52, fig. 72; Bennett, 1966: 41, pi. 9, fig. 
2; Morton & Miller, 1968: 472, fig. 175.5; Cemohorsky, 
1972: 198, pi. 56, fig. 10; Powell, 1976: 107, pi. 17, fig. 
30: Kay, 1979: 158, fig. 55C; Powell, 1979: 254, pi. 48, 
fig. 21; Fretter & Graham, 1982: 394, fig. 281; Kilburn 
& Rippey, 1982: 79, pi. 11, fig. 19; Wells & Bryce, 
1986: 60, fig. 153; Wilson, 1993: 281, pi. 44, figs 37a-b; 
Giannuzzi-Savelli etal., 1999: 52,53, figs 94a-d, 95a-b; 
Smith, 1998: 813, figs 15.151C, G; Morley, 2004: 102; 
Robertson, 2007a: 5, fig. 1; Beu & Marshall, 2008: 285; 
Poppe, 2008: 722, pi. 306, fig. 1; Spencer et al, 2009: 
206; Raven & Bracegirdle, 2010: 27, text-fig.; Willan et 
al. , 2010: 385, text-fig.; Grove, 2011: 40, pi. 18, fig. 9; 
Sevems,2011: 198, pi. 82, fig. 1; Hernandez etal, 2011: 
97, figs 30A-D. 
Ianthina exigua.-G. B. Sowerbyl, 1822: 2nd Janthina page, 
pi. 191, figs 2-3; Bronn, 1826: 328; d’Orbigny, 1841:414; 
Reeve, 1842: 145, pi. 205, figs 2-3 (repeat of Sowerby’s 
1822 figs); d’Orbigny, 1846: 84; Forbes & Hanley, 1853, 
vol. 2: 555, pi. 69, figs 8-9; H. Adams & A. Adams, 1854: 
87; Reeve, 1858: pi. 5,figs21a-b; Chenu, 1859: 118, fig. 
519; Benson, 1860: 408;Angas, 1865: 190;Angas, 1867: 
231; Hutton, 1873a: 6; Martens, 1873: 39; Tenison Woods, 
1878: 43; Hutton, 1880: 71; G. B. Sowerby II, 1882: 51, 
pi. 444, figs 23-24; Watson, 1886: 134; Tryon, 1887: 
37, pi. 10, figs 17-22; Whitelegge, 1889: 262; Focard, 
1898: 4; Pritchard & Gatliff, 1900: 140; Tate & May, 
1901: 407; Martens, 1904: 143; Verco, 1908: 9; Iredale, 
1910: 71; Macpherson & Chappie, 1951: 124; Faursen, 
1953: 22, figs 22-24; Macpherson, 1958: 33, pi. 29, fig. 
4; Macpherson & Gabriel, 1962: 119, fig. 146. 
Janthina incisa Philippi, 1849: 149; H. Adams & A. Adams, 
1854: 87; Tryon, 1887: 38. 
Ianthina nana J. E. Gray, 1850: 9,101 (caption to M. E. Gray, 
1842: pi. 48, figs 3^1). 
Ianthina incisa Philippi.-H. Adams & A. Adams, 1854: 87. 
Ianthina bifida “Nuttall in Jay” Reeve, 1858: pi. 5, figs 25a-b. 
Janthina capreolata Montrouzier, 1860: 114, pi. 11, fig. 4; 
Hedley, 1918: M61; May, 1921: 63; May, 1923: pi. 19,fig. 
4; Fischer-Piette, 1950: 18; Allan, 1950: 95, text-fig. 22.4. 
Janthina (Janthina) nana Gray.-Morch, 1860: 281. 
Janthina (Iodina) exigua Famarck .-Morch, 1860: 282; 
Powell, 1946: 77, pi. 10, fig. 30; Powell, 1957: 98, pi. 
10, fig. 30; Powell, 1962: 91, pi. 10, fig. 30. 
Janthina (Iodina) capreolata Montrouzier.-Morch, 1860: 
283. 
Janthina (Iodina) bifida Nuttall.-Morch, 1860: 283. 
Ianthina vinsoni Deshayes, 1863: 94, pi. 11, figs 9-11. 
Jodina exigua (Famarck).—Monterosato, 1884: 106. 
Janthina courcellei Mabille & Rochebrune in Rochebrune 
& Mabille, 1889: 45, pi. 6, figs 3a-b [courcelli in text, 
courcellei in caption; the latter adopted by Rosenberg 
(Malacolog 4.1.1)]; Forcelli, 2000: 82, original illus. 
copied; Petit, 2010: 48. 
Janthina (Jodina) exigua Famarck.-Thiele, 1929: 225, fig. 
228; Abbott, 1974: 113, col. pi. 3, fig. 1181; Rios, 1994: 
102, pi. 33, fig. 416. 
