Taxonomic review of the genus Adelomelon ( Gastropoda ; Volutidae ) , based on type material

The genus Adelomelon Dall, 1906 comprises a group of South American marine gastropods. We present updated information on the genus Adelomelon, with emphasis on the status and location of type material, including that of junior synonyms. Scaphella arnheimi Rivers, 1891 and Voluta paradoxa Lahille, 1895 are removed from the synonymy of Adelomelon ancilla (Lightfoot, 1758) and Adelomelon barattinii Klappenbach and Ureta, 1966 is included. The subgenus Weaveria Clench and Turner, 1964 is placed in synonymy with Adelomelon s.s. A key to the species of Adelomelon is provided.


Introduction
The genus Adelomelon Dall, 1906 was described to accommodate a group of South American gastropods, to which Dall (1906) referred as a "dull-colored group of South American volutes".Clench and Turner (1964) substantially revised the genus and resolved several taxonomic problems, especially regarding the proper identification of Adelomelon ancilla (Lightfoot, 1786) and Odontocymbiola magellanica (Gmelin, 1791).
Clench and Turner (1964) also described the species Adelomelon riosi, which they assigned to a new subgenus, Weaveria.The subgeneric arrangement proposed by Clench and Turner (1964) is still accepted by many authors.It consists of seven species distributed in three subgenera: Adelomelon s.s., Weaveria Clench andTurner, 1964, andPachycymbiola Ihering, 1907.In a subsequent paper, Clench and Turner (1970) proposed that Adelomelon (?) subnodosa (Leach, 1814) be transferred to Odontocymbiola Clench and Turner, 1964, based on the anatomy of its radula.Poppe and Goto (1992) proposed that the genera Adelomelon and Odontocymbiola are synonyms, although Adelomelon has radular teeth cuspids in the same plane and very short racemose salivary ducts, whereas Odontocymbiola has strongly curved, "fang-like" teeth, and very long racemose salivary ducts, as described by Clench and Turner (1964).Furthermore, Poppe and Goto (1992) proposed that the subgenus Pachycymbiola be elevated to genus status based solely on conchological characters; however, this arrangement has not been widely accepted and even criticized (Bondarev, 1996).
Herein, we present updated information on valid names and junior synonyms in the genus Adelomelon based on type material.

Material and Methods
This study is based on examination of type material and, in some cases, on high-resolution photographs sent by curators, together with comparisons of the original descriptions.
Institution names and abbreviations are as follows
Remarks: Lightfoot (1786) made reference to two specimens in the Duchess of Portland Collection (which was later auctioned), and to Davila and Romé de L'Isle (1767).None of these specimens, considered syntypes under ICZN (1999) article 73.2.1, could be located, and were presumed lost by Clench and Turner (1964).According to Weaver and duPont (1970), Voluta ancilla Lightfoot, 1786 and Voluta spectabilis Gmelin, 1791 are based on the same type material [illustrated by Davila and Romé de L'Isle (1767)] and therefore must be considered objective synonyms.
According to Clench and Turner (1964), the long-lasting confusion regarding A. ancilla and O. magellanica began when Lamarck (1811) described his V. magellanica (= ancilla Solander), non Gmelin, 1791, making Chemnitz' name available with a direct bibliographic reference.Many subsequent authors perpetuated Lamarck's misidentification, until Clench and Turner (1964) described the radular morphology and properly distinguished both taxa.At our request, Dr. Yves Finet located Lamarck's type material housed at MNHG 1103/31 (Figure 1), and Dr. Ole Tendal located Chemnitz' syntype in the Spengler Collection, housed at ZMUC.The similarity between specimen MNHG 1103/31 and the illustration by Küster (1845) on Plate 31, Figure 6 (reproduced in Figure 2) is note worthy but we could not determine whether Lamarck´s specimen was actually illustrated by Küster (1845).Lahille (1895) remarked that the characters given by Rochebrune and Mabille (1889) to describe V. bracata could not distinguish it from A. ancilla.At our request, Dr Jacques Le Renard (in 2004) located the two syntypes mentioned by Rochebrune and Mabille (1889) housed at MNHN.Weaver and duPont (1970) indicated that the individuals described as Voluta martensi Strebel, 1906 are only specimens of A. ancilla that show longitudinal ribbing on the early whorls.This observation was confirmed by our observation of syntypes from ZMB 18483 and 108666 (Figures 3-5).Two syntypes, stated by Strebel (1906) to be housed in ZMUH, were destroyed by bombing during World War II, according to Dr. Bernhard Hausdorf (in 2004, pers. comm.).
Adelomelon barattinii Klappenbach and Ureta, 1960 is very rare, and only empty shells have been reported (Carranza, 2005).Rios (1994) stated that A. barattinii is only a gerontic form of A. ancilla.Our examination of the holotype and paratype of A. barattinii, some specimens from the private collection of Mr. Juan Carlos Zaffaroni (Uruguayan Malacological Society) and the report of Carranza (2005) confirmed that A. barattinii is only an extreme variation of A. ancilla.We observed a great deal of variation in the size of nodules on several specimens, which otherwise could be taken as A. ancilla.We therefore consider A. barattinii very similar to A. ancilla form martensi, in which nodules present on the early whorls of the spire continue to the body whorl.Klappenbach and Ureta (1966) stated that the paratype of A. barattinii was housed in the private collection of Dr. Ureta.After his passing, the paratype was donated to the MNHM collection and assigned to lot MNHM 15134.
Rivers described Scaphella arnheimi in 1891, in an article in the Proceedings of the California Academy of Sciences.In the following year, the article was reprinted in The Nautilus.Neither of these articles provided an illustration of the specimen, or named a depository institution.Rivers (1891) reported one specimen trawled in Monterey Bay, a location noted to be in error by Clench and Turner (1964) and Weaver and duPont (1970), without further discussion.Although the correct classification of this taxon will only be possible after a proper examination of the type material, attempts to locate this material were unsuccessful.Shell description and type locality would lead us to compare S. arnheimi with the genus Arctomelon Dall, 1915, and until the material can be located, we propose this taxon to be considered incertae sedis and removed from the synonymy of A. ancilla as given by Clench and Turner (1964) and Weaver and duPont (1970).Weaver and duPont (1970) considered Adelomelon paradoxa (Lahille, 1895) a valid species, but remarked that some specimens illustrated by Lahille (1895) belong to Odontocymbiola magellanica (Gmelin, 1791).Poppe and Goto (1992), on the other hand, indicated Voluta paradoxa Lahille, 1895 in the synonymy list of A. ancilla.Our examination of the syntypes illustrated by Lahille (1895) and deposited in MLP, indicated that all specimens are actually O. magellanica, and therefore the taxon should be removed from the synonymy of A. ancilla and considered a synonym of O. magellanica.Weaver and duPont (1970) referred to the holotype of Voluta paradoxa Lahille, 1895 as having been deposited at BMNH, as lot 1901.8.1.35.This indication is in error, as this lot number refers to the holotype of Cymbiola mangeri Preston, 1901(Dr. Kathie Way, pers. comm., 2004), which is a synonym of V. paradoxa Lahille, 1895.The V. paradoxa type series (nine syntypes) is deposited at MLP.
Kiener (1839) also referred to material brought to Paris by d'Orbigny when returning from his voyage to southern South America, which was later incorporated into the British Museum Collection (BMNH) and listed by Gray (1854).However, when listing the specimens brought from this voyage, d'Orbigny (1841) did not mention Voluta fusiformis, but instead Voluta festiva Lamarck, 1811 and Gray (1854) remarked on this speci- men as being a young V. beckii.Strebel (1906) remarked that d'Orbigny´s collection arrived in Paris in 1847 and at that time, d'Orbigny most probably identified his material as V. festiva based on Lamarck´s writings, which had no illustrations.The d'Orbigny specimen is now housed at BMNH (lot 1854.12.4.427), and should be regarded as a syntype of Voluta fusiformis Kiener, 1839, by its reference in the original description.Concerning V. festiva sensu d'Orbigny (Figure 7), it has long been known that his identification was in error.Therefore, Voluta festiva Lamarck, 1811 is restricted to West Africa, as thoroughly discussed by Lahille (1895) and Strebel (1906).
Adelomelon indigestus Ihering, 1908 was described based on two specimens collected in southeast Brazil.The taxonomic status and type locality were discussed by Wiggers and Veitenheimer-Mendes (2005).
Remarks: Adelomelon riosi (Figure 8) commonly has, besides the fine spiral lines, flat, axially elongated nodules restricted to early whorls, similar to those of A. ancilla form martensi.We believe that this characteristic has no taxonomic importance.
Diagnosis: Shell globose without brown zigzag markings, spire low, apex globose to mammillated, and protoconch without a calcarella.
Remarks: Ihering (1907) proposed the subgenus Pachycymbiola to accommodate two recent species (A.brasiliana and A. ferussacii) and one fossil species (A.ameghinoi).According to Ihering (1907), Pachycymbiola is characterized by heavy and globose shells, a low spire, and uniform color.Remarks: The type location restricted by Weaver and duPont (1970) as "the estuary of the Rio Grande do Sul, southern Brazil" does not refer to any specific location and is doubtful.The indication of Weaver and duPont (1970) probably refers to the estuary of the Patos Lagoon, Rio Grande city, Rio Grande do Sul, southern Brazil, because it is the major estuary of the region.Still this is a doubtful assumption.Moreover, A. brasiliana is not an estuarine species, and restriction of the typelocality to an estuary may lead to erroneous conclusions regarding the animal's habitat.Therefore, we find no reason for such type locality restriction.

Adelomelon brasiliana (Lamarck, 1811)
The "Holotype" [sic] of A. brasiliana, which was stated by Kiener to be in the Paris Museum, could not be located by Dr. D. F. McMichael in 1961(fide Clench and Turner, 1964), nor by Dr. Le Renard in 2004 (pers. comm.), and is therefore presumed lost.The two specimens described by Chemnitz (1795) and referred to in Lamarck's description must, under ICZN (1999) article 73.1.4,be considered part of the type series.
The specimen illustrated by Chemnitz ( 1795) is part of the Spengler Collection, and Dr. Ole Tendal (pers.comm.)located it in 2004, housed in the ZMUC Collection (Figure 9).This specimen, being the sole traceable specimen in the type series, is here designated as a lectotype, to assure correct usage of the taxon name.The specimen mentioned but not illustrated by Chemnitz (1795) could not be located; still, it must be considered a paralectotype, as well as Lamarck's Paris Museum specimen.
Although not a usual case, the specimens cited by Chemnitz (1795) and considered the lectotype and paralectotype of V. brasiliana Lamarck, 1811, should be name-bearing syntypes of Voluta colocynthis because Dillwyn (1817) made the taxon name available, with a direct reference to Chemnitz (1795) (ICZN, 1999;articles 11.5 and 72.6).Therefore, V. brasiliana and V. colocynthis are objective synonyms.
Remarks: Donovan (1824) described V. ferussacii (Figure 10) with two spellings in the same text.In the title, he spelled the species name "Voluta ferussacii", and further on in the species description he spelled it "Voluta ferrusacii".Given the principle of priority and the dedication of the species to the Baron of Ferussac, the cor-rect spelling should be the first presented, i.e., Voluta ferussacii Donovan, 1824.Weaver and duPont (1970) stated that the holotype of A. ferussacii is housed in the BMNH under No.19920177 (Figure 11), but the indication is in error because this lot number refers to the holotype of V. rudis Griffith and Pidgeon , 1834(Dr. Kathie Way, pers. comm., 2004).The holotype of A. ferussacii could not be located and is probably lost.Lahille (1895) illustrated several specimens of V. oviformis (some are illustrated more then once in different plates).Among the material figured, 19 are here recognized as syntypes (Table 1).Three specimens were expressly stated to be variants, and therefore should not be considered syntypes under ICZN (1999) article 72.4.1.All specimens are housed in the MLP.

Subgenus Adelomelon s.s.
Shell globose to fusiform, medium to large, generally with elongated spire.Aperture large, semi-circular.Columella with one to five oblique folds.Surface smooth or with knobs at the whorl shoulder.Radula with a single row of flat tricuspid teeth.

Table 1 .
List of specimens figured by Lahille (1895) as V. oviformis.Specimens marked with * should not be considered syntypes.All specimens housed in MLP (unnumbered).