Lophiotoma jickelii, (WEINKAUFF, 1875)

Puillandre, Nicolas, Fedosov, Alexander E., Zaharias, Paul, Aznar-Cormano, Laetitia & Kantor, Yuri I., 2017, A quest for the lost types of Lophiotoma (Gastropoda: Conoidea: Turridae): integrative taxonomy in a nomenclatural mess, Zoological Journal of the Linnean Society 181, pp. 243-271 : 263-265

LOPHIOTOMA JICKELII ( WEINKAUFF, 1875)

( FIG. 11)

Pleurotoma jickelii Weinkauff, 1875 in Weinkauff & Kobelt, 1875 –1887: 20, pl. 4, figs 2, 3 (Massaua, Red Sea).

Lophiotoma acuta form jickelii . – Powell, 1964: 305, pl. 180, figs 14, 19.

Type material: Neotype MNHN IM-2013-13275 (here designated).

Type locality: Papua New Guinea, Tab Island , inner slope, 05°10.2′S, 145°50.3′E (Expedition PAPUA NIUGINI, st. PR42) .

Description (neotype): Shell thin, fusiform ( Fig. 11A– C), with high spire and long narrow siphonal canal very slightly inclined to left. Protoconch conical ( Fig. 11D), of about 3.75 evenly convex whorls, posteriormost 0.75 whorl before transition to teleoconch with ten distinct arcuate ribs, more closely spaced towards transition to teleoconch. Protoconch diameter 1.0 mm, height 1.22 mm. Teleoconch whorls weakly angulated at shoulder, 10.5 in total. Suture moderately deep, distinct, subsutural region wide, distinctly concave. Subsutural cord distinct, narrow on upper four teleoconch whorls, rounded on top, with two additional angular ridges appearing in upper part of cord on 5th and subsequent whorls. Ridges become progressively stronger and on last whorl cord of three distinct sharp triangular in profile ridges, middle one most elevated. Subsutural region smooth on upper teleoconch whorls, with one spiral ridge appearing on third whorl, two on the fourth, three on fifth, up to six on the last whorl. Paired sinus cords strongest, separated by interspace four times wider than cords, broadly obtuse triangular in profile and of same strength on last whorl. On upper whorls both cords similar in size, very closely spaced on upper four whorls progressively broader spaced on later whorls. Base of spire whorls smooth on upper two whorls, with one spiral cord on the third to fourth whorl, two on fifth, and then fast enlarging in number up to 11, strongly different in size cords on penultimate whorl. Base of last whorl with 15 cords, five of which much more prominent; canal with 34 cords, becoming gradually lower anteriorly. Cords slightly nodulose on intersections with growth lines. Shell base sharply narrowing towards narrow and long nearly straight siphonal canal. Aperture pear shaped, strongly constricted posteriorly, with parietal callus producing distinct tooth, outer lip concave in upper part and strongly convex below shoulder, gradually passing into canal. Anal sinus deep, narrow, with nearly parallel sides, and nearly straight posterior margin, parallel to shell axis; outer lip in side view rounded and opisthocline, stromboid notch well-defined. Shell light brown, protoconch and two first teleoconch whorls slightly darker. Subsutural cord(s) with light brown irregularly shaped spots. Sinus cords with narrow and irregularly spaced brown spots, minor spiral cords with spots sometimes chevron shaped and smaller flecks. Aperture light creamy, lirated deep inside. Measurements (neotype largest of our specimens): SL 39.4 mm, AL (with canal) 19.8 mm, SW 10.7 mm. Radula (neotype) ( Fig. 5G) long, of about 65 rows of teeth, of which 25 nascent. Radula similar to other congeners, with duplex somewhat stout marginal teeth. Anterior (inner) half is solid, lanceolate, dorso-ventrally compressed with sharp lateral cutting edges. In posterior half major and accessory limbs bifurcate at about 45° angle, rather thin. Central formation distinct, of small sharp narrow cusp.

Remarks: The species is rather variable in terms of sculpture and coloration. All intermediate specimens can be found from very light, hardly speckled specimens from Vietnam ( Fig. 11K) to very dark ones from Mozambique, similar to the dark form of L. acuta ( Fig. 11J). Interestingly, the dark form was found only in Mozambique and the only two studied specimens from this region were dark. The degree of development of spiral cords (other than subsutural and sinus cords) can also be rather different: there can be as few as four subequal cords on the subsutural zone, up to six strongly unequal cords in the neotype. In all studied specimens, there are two or even sometimes three closely spaced cords immediately below the suture. On the contrary, in L. acuta and L. semfala sp. nov. the subsutural cord is single, sometimes with two much weaker additional threads running along it. This allows a reliable differentiation of L. jickelii from both L. acuta and L. semfala sp. nov. There seems to be geographically determined shell variability, with only dark forms sampled in Mozambique, and very light ones in Vietnam; however, very limited material available from the mentioned localities does not allow us to draw final conclusions. The species was for a long time considered to be a synonym of L. acuta ( Powell, 1964: 305 and many others), or a Red Sea subspecies of L. acuta . The name was used as a valid one recently for specimens from the Philippines ( Heralde et al., 2007; Fedosov et al., 2011), but its validity was never addressed from the viewpoint of taxonomy. The type of Pleurotoma jickelii Weinkauff, 1875 originated from C. Jickeli’s collection, which is now partially stored in the Humboldt Museum, Berlin (http://www. conchology.be/?t=9001&id=21727). Nevertheless, the types were not found in the Berlin Museum, nor in SMF, where the material of some other Weinkauff species is kept. Therefore, we consider them to be lost. The species was described from Massawa (presently Eritrea) based on a beach-collected specimen. The illustration of Weinkauff & Kobelt (1875 –1887): pl. 4, figs 2, 3) is a bit ambiguous and depicts the large shell (SL 53 mm) with poorly pronounced sinus cords and nearly straight sided bases of spire whorls, similar to those in our specimens. Powell (1964: pl. 180, fig. 19) illustrated a specimen of ‘form jickelii ’ from the Red Sea very similar to ours and provided an adequate and accurate description of Lophiotoma acuta form jickelii . Finally, Verbinnen & Dirkx (2007) discussed the occurrence of Lophiotoma acuta in the Red Sea and the status of L. acuta jickelii ( Weinkauff, 1875) . They illustrated the shell of acuta (fig. 21) as well as two shells which represent L. jickelii (21a, 21b). We were able to examine one shell, collected in Egypt ( Fig. 11O) and it, as well as specimens illustrated by Verbinnen & Dirkx, falls within intraspecific variability of a single species as defined herein by molecular data. In the absence of sequenced material from the Red Sea and due to the confusing situation with the taxonomy of the species, we designate herein the specimen collected in Tab Island, Papua New Guinea, Madang Lagoon ( Fig. 11A–C) as the neotype of Lophiotoma jickelii . The species is most similar to Lophiotoma kina sp. nov., found in Vanuatu and Papua New Guinea. For differences see the remarks for Lophiotoma kina sp. nov. The species can be readily distinguished from L. acuta by its less pronounced subequal sinus cords rounded on top, while in L. acuta the upper sinus cord is much more pronounced than the lower and both sinus cords have a sharp upper edge. Lophiotoma jickelii also differs from both L. acuta and L. semfala sp. nov. in that the subsutural cord is subdivided into several cords on the last and penultimate whorls in the former species while in the latter two it is uniform with a sharp upper edge and very weak additional ridges. The studied radula of L. jickelii has a broader anterior solid part of marginal teeth and a more pronounced cusp on the central formation.

Distribution: Confirmed distribution of the species (based on sequenced specimens) – tropical Indo-West Pacific from Mozambique to Vietnam, Philippines, Papua New Guinea, Vanuatu. Based on published data also the Red Sea.