Beu: Evolution of Janthina and Recluzia 
171 
Diagnosis. Teleoconch moderately large (to c. 40 mm 
wide), whorls evenly convex; most specimens heliciform 
throughout growth, spire consistently low; completely 
covered with fine, closely spaced axial ridges; 8-12 evenly 
convex spiral folds per whorl (9 or 10 on most specimens) 
over entire teleoconch surface, as prominent on sutural 
ramp as elsewhere. Outer lip sinus relatively small, narrow, 
semicircular, located at base of lip, generating lowermost, 
wide spiral fold parallel to columella. Protoconch not seen. 
Original description. Bronn’s (1861: 119-120) original 
description of Hartungia typica reads: “ Hartungia typica 
n. g. sp. [new genus and species], A very delicate thin and 
also Ianthina- like shell, filled with rock, 18 mm high and 
22 mm wide, with three whorls, which (as in I. communis) 
[i.e., Janthina janthina ] form a flatly arched upper side and 
of which the first two [whorls] are only 5 mm in height. In 
contrast, the wide ovate aperture measures 17 mm in height 
and 15mm in width, while its complete lower edge (as in 
I. nitens Menke) [i.e., Janthina globosa ] wraps around 
vertically towards the base. In the same way the umbilicus 
is not open, but is just in the form of a narrow chink behind 
the inner lip, which lies conspicuously on the penultimate 
whorl, as in the said species. The dense fine and elegant 
vertical striation also recalls it [presumably referring to 
Janthina exigua ], but does not form a re-entrant sinus in the 
middle of the outer lip as in Ianthina , but is straight there; 
in contrast, further down opposite the end of the umbilical 
chink, [the striation] bends in on a spiral rib [to form] a 
somewhat insignificant small arch [sinus]. However, what 
distinguishes this gastropod immediately from all known 
Ianthina species and would better accord with Narica are 
8 flat, broadly rounded spiral cords, which extend down 
along the outermost convexity of the last whorl, remaining 
somewhat distant from the suture and even more from the 
umbilicus, and [of] which the fourth, without forming a keel, 
is situated furthest towards the outside and scarcely exceeds 
its upper and lower neighbours in strength. The height of two 
spiral cords conforms to the width of 6-7 vertical striations. 
Thus this species is distinguished from Ianthina by the form 
of the sinuosity and the sculpture of the shell, with which it 
stands closely in a family and seems to form its own genus, 
which we name after the indefatigable explorer of the west 
European islands. This genus probably has some similarity in 
shape and lip sinus with Neritoma Morris from the Portland 
beds, but Neritoma is bi-sinuate, somewhat thick-shelled and 
not umbilicate, behind the inner lip somewhat canal-forming, 
the growth lines simple. The shell seems too thin for the early 
whorls of a Magilus and the aperture too regular” (slightly 
modified translation from German by T. A. Darragh, NMV, 
pers. comm. 12 Nov 2015). 
Remarks. Bronn (1861:119-120) compared Hartungia typica 
with “ Ianthina ” species in several places in his description, 
stating that it “stands closely in a family” with Janthina , and 
clearly regarded Hartungia as a new genus of Janthinidae. He 
appreciated that H. typica is similar to living Janthina species, 
differing in its small basal sinus and the presence of spiral 
folds. Mayer (1864: 62) later redescribed the same species in 
Janthina , apparently changing the species name to maintain 
the association with the collector, Georg Hartung. 
Mayer’s (1864b: i-ii) foreword explained that Bronn 
had died, and so Hartung asked Mayer “in the autumn of 
1861” to describe the fossils collected by Reiss at Madeira 
and Porto Santo. On examining the fossils he found they 
had a lot in common with those described by Bronn in the 
works by Hartung and Reiss on the Azores. Therefore, he 
thought the whole assemblage should be written up together, 
and asked Hartung and Reiss to help arrange a loan of 
Bronn’s material from the University of Heidelberg. “With 
the greatest willingness Professors Blum and Pagenstecher 
immediately fulfilled my wish, sending me the material able 
to be found, and so in the first half of the last winter I could 
attend to my expanded task” (translation from German by T. 
A. Darragh, NMV, pers. comm. 12Nov 2015). This statement 
suggests that some of Bronn’s material already could not 
be traced in 1861. Mayer (1864: 62) listed the description 
of Hartungia typica by Bronn (1861: 119, pi. 19, fig. 3) 
in a chresonymy below the species heading for Janthina 
hartungi, along with the listing of H. typica by Bronn in 
Reiss (1862: 32). So it is clear that he renamed Bronn’s 
species, although he did not state a reason for doing so. He 
also compared Janthina hartungi with J. communis (i.e., J. 
janthina) and with J. capreolata Montrouzier (i.e., J. exigua). 
He stated the dimensions as “Alt. 19, lat. 22 mill.”, only 
subtly different from the dimensions of 18 mm high and 22 
mm wide provided by Bronn (1861: 119). The list of material 
at the end of the description makes it clear that Mayer had 
actual shells before him, as he said the six examples he had 
included three typical ones from Feiteirinhas (i.e., Ponta das 
Salinas), another from “Ponta dos Mattos” (presumably the 
modelling clay impression in Fig. 24M), one without spiral 
folds from Pinheiros and one with weak folds from Sao 
Vicente (Madeira). The lack of an express statement of a 
type specimen suggests that Mayer regarded all these as type 
material of J. hartungi. Mayer’s and Bronn’s illustrations are 
particularly similar, including the unusual lateral view of the 
angular columellar base. As Mayer had Bronn’s material 
before him, the very similar illustrations (Mayer’s: copied 
as Figs 25D-F; Bronn’s: copied as Figs 250-P, S) likely are 
different artist’s drawings of the same specimen. In view of 
the brittleness of Janthina fossils, this material possibly has 
disintegrated over the intervening years. 
Janthina typica is characterized by its moderately 
large size, reaching about 40 mm in diameter and 38 mm 
in height, although most specimens are 25-35 mm in 
diameter; its consistent, more-or-less equidimensional, 
heliciform shape, with a moderately low spire; the few, 
rapidly expanding teleoconch whorls; the low, thin, closely 
spaced axial ridgelets covering the entire teleoconch surface, 
about 1 mm apart over the periphery of large specimens; the 
quite prominent, evenly convex spiral folds with equally 
wide, evenly concave interspaces that also cover the entire 
teleoconch surface, 8-12 on the last whorl (most specimens 
have 9 or 10 folds), visible on spire whorls as well as on the 
last whorl; and its relatively small, semicircular sinus in the 
outer lip, situated at the base of the lip against the columella 
base. In most specimens, the sinus generates a particularly 
prominent, wide spiral ridge parallel to the other spiral folds 
and to the columella and the inner lip of the aperture, higher 
and wider than the normal spiral folds, although this basal fold 
is not obviously differentiated in a few specimens. The whorl 
outline is regularly and strongly convex on most specimens, 
although a few large shells develop a slightly to quite strongly 
concave sutural ramp over the last half-whorl. Some of these 
develop a thickened, smoothly rounded lip edge over the 
concave area, whereas the lip edge is simple and thin in all 
