Berthelinia Crosse, 1875

McCarthy-Taylor, Jennifer B., Krug, Patrick J., Muro, Sandra, Vendeti, Jann, Maestrati, Philippe, Wong, Nur Leena W. S., Gosliner, Terrence M. & Valdés, Ángel, 2025, Te slug within the bivalve: molecular and morphological systematics of the family Juliidae (Gastropoda: Panpulmonata: Sacoglossa), Zoological Journal of the Linnean Society 204 (2) : -

Genus Berthelinia Crosse, 1875

† Berthelinia Crosse 1875: 79 . Type species: Berthelinia elegans Crosse, 1875 , by monotypy.

† Ludovicia Cossmann 1887: 45 . Type species: Ludovicia squamula Cossmann, 1887 , by monotypy.

† Anomalomya Cossmann 1887: 169–170 . Type species: Anomalomya corrugata Cossmann, 1887 , by monotypy.

† Cossmannella Boetger 1962: 414 [non Cossmannella Mayer-Eymar, 1896 ; Bivalvia ], unnecessary replacement for Ludovicia Cossmann, 1887 .

† Squamulina Le Renard 1989: 23 [not Squamulina Schultze, 1854 ; Foraminifera], replacement name for Cossmannella Boetger, 1962 .

Diagnosis

Shell thin, delicate, semi-quadrangular in lateral view; anterior margin rounded, narrowing posteriorly, tapering into round tail end; shell tallest point near anterior end; right valve slightly smaller; hinge with inconspicuous condyloid (or cardinal) tooth on right valve, lef valve with fossete-like socket; protoconch on lef valve, slightly behind mid-length point; single, adductor muscle scar subcentral.

Remarks

Crosse (1875) introduced the genus name Berthelinia Crosse, 1875 based on a single specimen collected in the Miocene of the Paris Basin (Courtagnon), which he described as a new species, Berthelinia elegans . Because Crosse (1875) had only one valve, and owing to its small size and reduced number of whorls, he speculated that it could be an embryonic shell. Crosse (1875) struggled with the taxonomic placement of this species and suggested that it was probably related to the gastropod genera Pileopsis Lamarck, 1822 [= Capulus Montfort, 1810 , family Capulidae Fleming, 1822 ] or Hipponyx [incorrect spelling of Hipponix Defrance, 1819 , family Hipponicidae Troschel, 1861 ]. Fischer (1886) suggested, for the first time, that Berthelinia was a bivalve, possibly related to the Prasinidae Stoliczka, 1871 (a synonym of Juliidae ) or Aviculidae Goldfuss, 1820 [= Pteriidae ].

Cossmann (1887) formally described the genus Ludovicia Cossmann, 1887 (Deshayes’ manuscript name), for the new species Ludovicia squamula Cossmann, 1887 , based on the shells from the Eocene of the Paris Basin. Cossmann (1887) placed Ludovicia in the bivalve family Galeommidae [sic.] [= Galeommatidae Gray, 1840 ]. Hedley (1920) indicated that W. J. Wintle pointed out to him that Ludovicia Cossmann, 1887 is preoccupied by the genus name Ludovicius Rondani, 1843 , because according to Marschall (1873) this name was rendered as Ludovicia by Rondani (1845). Boetger (1962) agreed with this assessment and proposed the replacement name Cossmannella Boetger, 1962 for Ludovicia Cossmann, 1887 . However, a review of the pertinent literature shows that Rondani (1843) introduced the new genus name Ludovicius in the family Dolichopoda [ Diptera ]. Subsequently, Rondani (1845) reported the name Ludovicius again with the same spelling, and Marschall (1873: p. 336) listed the name as ‘Ludovicia’ with authorship of Rondani, 1845. Because there is no evidence that Marschall’s (1873) spelling was an intentional emendation ( ICZN 1999: Article 33.2), it is considered here as an incorrect subsequent spelling ( ICZN 1999: Article 33.5) and therefore unavailable for the purposes of homonymy. Tus, Ludovicia Cossmann, 1887 remains available, and Cossmannella Boetger, 1962 is an unnecessary replacement. Later, Le Renard (1989) noticed that Cossmannella Boetger, 1962 was preoccupied by Cossmannella Mayer-Eymar, 1896 [ Bivalvia] and proposed the replacement name Squamulina Le Renard, 1989 , which is also preoccupied by Squamulina Schultze, 1854 [Foraminifera].

Cossmann (1887) described additional bivalve taxa in the family Prasinidae , including the new genus Anomalomya Cossmann, 1887 , based on the new species Anomalomya corrugata Cossmann, 1887 . Cossmann (1887) also examined additional specimens of Berthelinia elegans , which he formally placed in the Prasinidae . Cossmann (1887) noticed that specimens of Berthelinia from Le Ruel (Haravilliers, France) differed slightly from those found in coarse limestone, and introduced a variety, Berthelinia elegans elata , for those specimens.

Crosse and Fischer (1887) commented further on the taxonomic placement of Berthelinia in Pelecypoda (= Bivalvia) based on newly discovered complete specimens of B. elegans that included both valves and with visible muscle scars. Crosse and Fischer (1887) had difficulties placing Berthelinia among bivalves and speculated that it was probably related to the families Aviculidae and Prasinidae as suggested by Fischer (1886). In a postscript in the same article, Crosse and Fischer (1887) mentioned that afer their paper was writen, they received the second delivery of Cossmann’s (1887) illustrated catalogue of the fossil shells of the Eocene of the environs of Paris, where this author placed Berthelinia in the family Prasinidae .

Te discovery of the first live bivalved sacoglossans by Kawaguti and Baba (1959) prompted the reclassification of Berthelinia as a gastropod ( Burn 1960b, Keen 1960b); see remarks on Edentellina . Based on morphological similarities, some authors considered Ludovicia and Anomalomya as subgenera of Berthelinia (Keen & A. G. Smith 1961; Boetger 1962), whereas others maintained them as separate genera ( Le Renard et al. 1996, Schneider et al. 2008).

In this study, morphological evidence indicates that Berthelinia cannot be used for Recent species. Te PCA recovered Recent and fossil species of Berthelliniinae in two distinct clusters, indicating that they are morphologically distinct. Terefore, the genus Berthelinia is used herein only for the extinct taxa listed below.

Species list

† Berthelinia elegans Crosse 1875: 79–81 , pl. 2, fig. 3. Type locality: Courtagnon , France (Eocene) .

† Ludovicia squamula Cossmann 1887: 45–46 , pl. 2, figs 21, 22. Type locality: Parnes , France (Eocene) .

† Anomalomya corrugata Cossmann 1887: 170 , pl. 7, figs 30, 31. Type locality: Le Fayel, France (Late Eocene) .

† Berthelinia elegans elata Cossmann 1887: 175 , pl. 7, figs 24–27. Type locality: Le Ruel, France (Early–Late Eocene) .

† Berthelinia? elongata Cossmann 1906: 262–263 , pl. 20, figs 18, 19. Type locality: Bois-Gouët , Loire-Atlantique, France (Early Eocene) .

† Berthelinia burni Ludbrook and Steel 1961: 229 , pl. 12. Type locality: Elizabeth Oval bore, Hundred of Munno Para, 15 miles north of Adelaide, Australia (Early Pliocene) .

† Berthelinia oligocaenica Janssen 1979: 75–78 , figs 1, 2 (Middle Oligocene).

Genus Namnetia Cossmann, 1905 † Namnetia Cossmann 1905b: 147 .

Type species: Namnetia discoides Cossmann, 1905 , by monotypy.

Diagnosis

Shell thin, delicate, ovoid, nearly round in lateral view; anterior and posterior margins rounded, similar in height, or posterior end narrower, sharper; shell tallest point near centre; hinge with anterior and posterior parts interrupted beneath apex, condyloid (or cardinal) tooth on right valve, lef valve with fossete-like socket; protoconch on lef valve, near mid-length point; single, adductor muscle scar nearly central.

Remarks

Cossmann (1905b) introduced the new genus Namnetia Cossmann, 1905 for the species Namnetia discoides Cossmann, 1905 and provisionally placed it in the family Galeommidae [sic.] [= Galeommatidae Gray, 1840 ]. Le Renard (1980) described the new Juliidae species Anomalomya ( Namnetia ?) sphaerica Le Renard, 1980 . Le Renard (1980), based on this interpretation of the original description of Namnetia discoides by Cossmann (1905b), suggested that Namnetia could be a subgenus of Anomalomya and belong to the family Juliidae . Tis placement has not been confirmed with the examination of specimens. Le Renard (1989) examined additional specimens of this group and, using morphometric data, confirmed the placement of Namnetia in Juliidae . Le Renard (1989) also considered Anomalomya sphaerica Le Renard, 1980 as a possible synonym of Anisodonta sphaericula Cossmann, 1886 , and proposed both as members of Namnetia . Finally, Le Renard (1989) pointed out the similarities between Namnetia and Anomalomya but preferred to maintain them as separate genera.

Species list

† Anisodonta sphaericula Cossmann 1886: 141–142 , pl. 2, figs 34–36. Type locality: Valmondois , France (Late Eocene) .

† Namnetia discoides Cossmann 1905b: 147 , pl. 9, figs 47–49. Type locality: Bois-Gouët , Loire-Atlantique, France (Middle Eocene) .

† Anomalomya sphaerica Le Renard 1980: 21–23 , fig. 11. Type locality: Baron , Oise, France (Middle Eocene) .

Genus EdenTellina Gatliff & Gabriel, 1911 Edentellina Gatliff & Gabriel 1911: 190 . Type species: Edentellina typica Gatliff & Gabriel, 1911 , by original designation.

Tamanovalva Kawaguti & Baba 1959: 178–179 . Type species: Tamanovalva limax Kawaguti & Baba, 1959 , by original designation.

Midorigai Burn 1960b: 45–46 . Type species: Midorigai australis Burn, 1960 , by original designation.

Diagnosis

Shell thin, delicate, translucent, colourless, semi-quadrangular in lateral view; anterior margin rounded, narrowing posteriorly, tapering into sharp tail end; shell tallest point near anterior end; right valve slightly smaller; hinge with faint corrugations, lacking teeth or with small condyloid (or cardinal) tooth on right valve, lef valve ofen with reduced triangular hinge socket; protoconch on lef valve, slightly behind mid-length point; single, adductor muscle scar subcentral; gill occupies height of right valve; heart dorsally in mantle fold; intestine on surface of mantle floor, behind bulge formed by female reproductive system; mantle cavity covering only right side of the body; radular teeth elongate, blade-shaped, with row of hair-like denticles along each side; teeth cusps either with single sharp tip or bifid.

Remarks

Dautzenberg (1895) reported the first Recent shell of the fossil genus Berthelinia based on a right valve (with the protoconch) collected by Schlumberg in Madagascar. Dautzenberg (1895) illustrated and described this shell as a new species, Berthelinia schlumbergeri , and commented on the taxonomic placement of this group in the Bivalvia (as Pelecypoda).

Gatliff and Gabriel (1911) described the genus Edentellina based on Recent specimens collected in Port Phillip, Australia. Gatliff and Gabriel (1911) designated their new species Edentellina typica Gatliff & Gabriel, 1911 as the type, but mentioned that a second species collected by C. Hedley also belonged to the same genus and was going to be described at a later date. Gatliff and Gabriel (1911) placed Edentellina among other bivalve species but did not discuss the taxonomic placement of this group or compare it with other previously described taxa in Bivalvia. Hedley (1912) suggested that Edentellina was not a bivalve (or pelecypod) but the internal shell of a tectibranch gastropod (obsolete term for some shelled sea slugs). Hedley (1912) also pointed out the similarity between Edentellina and the fossil genus Ludovicia Cossmann, 1887 . Years later, Hedley (1920) described a second Recent species of Edentellina , Edentellina corallensis , and commented that because this animal had a ligament joining the right and lef valves, it was clearly a bivalve. Additionally, Hedley (1920) examined the paratypes of Ludovicia squamula Cossmann, 1887 (the type species of Ludovicia Cossmann, 1887 , borrowed from Dautzenberg), and based on the morphological characteristics of these two taxa, considered Edentellina and Ludovicia to be congeneric, although he did not explicitly propose a formal synonymization of the two names. Additionally, based on similarities between Edentellina and J. exquisita, Hedley (1920) proposed the placement of Edentellina in the family Juliidae and related to the Chamacea [= Chamoidea Lamarck, 1809, Bivalvia].

Dall (1918) reported a third Recent species of this group based on two lef shells collected in Magdalena Bay, Baja California Sur, Mexico that he described as? Scintilla chloris . Because of the limited material available (only two valves, with no protoconch), Dall (1918) did not make the connection between his specimens and previous records by Dautzenberg (1895) and Gatliff and Gabriel (1911), thus he suggested his specimens should probably be placed in the bivalve genus Scintilla Deshayes, 1856 (family Galeommatidae Gray, 1840 ) until more material became available.

Kawaguti and Baba (1959) discovered the first live specimens of Sacoglossa with a bivalved shell, for which they proposed the new genus Tamanovalva and the new species Tamanovalva limax . Kawaguti and Baba (1959) were unaware of any other species of sacoglossans with such an unusual morphology, and therefore introduced the new family Tamanovalvidae and the new suborder Tamanovalvacea for this group. Kawaguti and Baba (1959) compared the shell of Tamanovalva with that of Edentellina , which they considered a member of Bivalvia, and concluded that they were different. However, Cox and Rees (1960) stressed the morphological similarities between Tamanovalva and Edentellina and with the fossil genus Ludovicia , and suggested that they could be synonyms. Keen (1960a) agreed with Cox and Rees (1960) but proposed that the fossil genus name Berthelinia could be a more senior synonym for this group.

Burn (1960a), in a brief note, described, for the first time, live specimens of Edentellina typica in Torquay, Victoria, Australia. Burn (1960a) also mentioned collecting a second species of the same group belonging to a different genus. In a second paper the same year, Burn (1960b) re-emphasized Tamanovalva as a synonym of Edentellina , but also proposed that these two genera are synonyms with the fossil genus Berthelinia from the Eocene of the Paris Basin, as suggested by Keen (1960a). Burn (1960b) confirmed that the species he collected from Victoria belonged to E. typica (renamed Berthelinia typica ) and that E. corallensis was a synonym, but that the specimens described by Verco (1916) as E. typica constituted a second, distinct species. Burn (1960b) suggested that T. limax described by Kawaguti and Baba (1959) was also a synonym of B. typica , and? Scintilla chloris Dall, 1918 (from Baja California), although larger, was probably another synonym of B. typica . Finally Burn (1960b) considered the second species he collected in Victoria to belong to a new genus that he named Midorigai , based on the new species Midorigai australis Burn, 1960 . According to Burn (1960b), the main differences between Midorigai and Berthelinia were the more swollen shape of the shell, the size and arrangement of the protoconch (in a horizontal plane across the hinge line), the presence of two adductor muscles, the foot narrower than the neck, and some other anatomical details.

In subsequent years, a number of papers described additional species of bivalved gastropods and provided alternative assessments of the taxonomy of this group. First, Keen (1960b) formally synonymized Tamanovalva with Edentellina and Berthelinia and suggested a close relationship with Julia , which was not yet known from live animals. Tis opinion was followed by Ludbrook and Steel (1961) in the description of the new species Berthelinia burni Ludbrook & Steel, 1961 [not Julia burni Sarma, 1975 ]. Baba (1961a) provided a comprehensive revision of the morphological characteristics of Tamanovalva and compared them with those of Edentellina and other shelled sacoglossans. Baba (1961a) also mentioned that Tamanovalva was different from Edentellina in shell and radula morphology, and that Edentellina seemed more similar to Ludovicia than to Tamanovalva , which appeared closer to Berthelinia . Baba (1961a) concluded that it is difficult to compare Recent and fossil taxa and more data are needed to establish a definitive taxonomy for the group, but should all these genera become synonyms, Berthelinia would have priority. In a second paper the same year, Baba (1961b) concluded that Berthelinia , Ludovicia , Edentellina , Tamanovalva , Midorigai , and possibly Anomalomya were synonyms and provided a detailed review of the radular and conchological characteristics of this group. Te same year, Keen and A. G. Smith (1961) described the new subspecies Berthelinia chloris belvederica and revisited the taxonomy of the bivalved sacoglossans, formally proposing that both Julia and Berthelinia were members of the family Juliidae . Keen and A. G. Smith (1961) also proposed that the genus Berthelinia included five subgenera, Berthelinia s.s., tentatively represented by three fossil taxa (including the type B. elegans ) and the Recent B. schlumbergeri ; Ludovicia , including only the type species L. squamula ; Anomalomya , represented by the type species A. corrugata and possibly a Recent undescribed species from Australia; Midorigai , represented only by the type species M. australis ; and Edentellina , including all other Recent species. Boetger (1962) followed a similar classification scheme to the one proposed by Keen and A. G. Smith (1961), but regarded Midorigai as a genus distinct from Berthelinia , instead of a subgenus, and proposed the new subgenus name Cossmannella to replace Ludovicia , which he erroneously thought was preoccupied (see remarks on Berthelinia ). Boetger (1962) also described the new fossil species Julia borneensis .

Additional records and new species from the Hawaiian Islands ( Kay 1962a, b, 1964), Berthelinia pseudochloris , and the Caribbean ( Edmunds 1962, 1963), Berthelinia caribbea , largely followed the classification scheme proposed by Keen and A. G. Smith (1961). However, Burn (1965) indicated that he considered Berthelinia an exclusively fossil genus and that the Recent genus Tamanovalva was distinct and included the species T. limax , E. corallensis , S. chloris . Burn (1965) also recognized that among the paratypes he described as M. australis ( Burn 1960b) , there were some specimens that belonged to the true E. typica as described by Gatliff and Gabriel (1911), a point already made by Baba (1961a). Burn (1965) concluded that the specimens he described in his earlier work ( Burn 1960b) as E. typica were different from those in the original description by Gatliff and Gabriel (1911) and belonged to the genus Tamanovalva , thus he introduced the new name Tamanovalva babai for them. Finally, although not clearly stated, Burn (1965) appeared also to consider Edentellina as a valid genus and distinct from both Tamanovalva and Berthelinia . Burn (1966) described a new species of Tamanovalva from Fiji, Tamanovalva fijiensis , and stated clearly that he considered Edentellina and Tamanovalva as distinct genera but did not provide distinguishing characters. Burn (1966) also distinguished Berthelinia and Tamanovalva because of the presence of one and a half whorls in the protoconch of Tamanovalva instead of two, as in the protoconch of Berthelinia .

Kay (1968) proposed a classification, informed by that of Keen and A. G. Smith (1961) and Boetger (1962), in which Midorigai was a subgenus of Berthelinia (because it possessed a uniquely swollen shell and two adductor muscle scars) and the subgenus Berthelinia could be applied only to fossils. Tis classification scheme was followed by some authors (e.g. Ganapati and Sarma 1972, Sarma 1975), but Jensen (1993, 1997a, b, 2015) synonymized all the subgenera under Berthelinia . Burn (1998, 2006) accepted Berthelinia and Tamanovalva as synonyms, but retained Edentellina and Midorigai as separate genera and continued to use Tamanovalva . Importantly, conchological traits ofen used to distinguish these genera are variable. For example, Edmunds (1963) found that the position of the protoconch varies within B. caribbea , and Jensen (1993) noted that the overall shape of the shell and the angle of the protoconch vary within B. rotnesti , with small specimens having a fairly erect protoconch and larger specimens having an almost horizontal one. Tus, it seems that owing to ontogenetic and/or intraspecific variability, these characters are not taxonomically informative.

In this study, molecular phylogenetic analyses revealed that the type species of Edentellina , Tamanovalva , and Midorigai belong in the same clade. Terefore, we find no compelling reasons to maintain these as different genera, and we agree with Jensen’s (1993) proposal to synonymize Edentellina , Tamanovalva , and Midorigai . However, geometric morphometric analyses revealed that fossil and Recent members of this group clustered in different groups, with significant morphological differences. Tus, we propose to maintain Berthelinia as a valid genus for fossil taxa and retain Edentellina (the oldest available name) for Recent species.

Species list

Berthelinia schlumbergeri Dautzenberg 1895: 37–38 , figs A, B. Type locality: Nosibé [= Nosy Be], Madagascar.

Edentellina typica Gatliff & Gabriel, 1911: 190 , pl. 46, figs 5, 6. Type locality: Portsea , Port Phillip, Victoria, Australia.

? Scintilla chloris Dall 1918: 5 . Type locality: Magdalena Bay , Baja California Sur, Mexico.

Edentellina corallensis Hedley 1920: 76 , figs 6–8. Type locality: Hope Island , Queensland, Australia.

Tamanovalva limax Kawaguti & Baba 1959: 179–180 , figs 1–10. Type locality: Vicinity of the former Tamano Marine Laboratory , Okayama University, by the Great Seto Bridge, Japan.

Midorigai australis Burn 1960b: 46 , figs 8–14. Type locality: Torquay , Victoria, Australia.

Berthelinia chloris belvederica Keen & A. G. Smith 1961: 53–61, figs 18, 19, 21–24, 27–32, pl. 5, lower fig. Type locality: Puerto Ballandra , near La Paz, Baja California Sur, Mexico.

Berthelinia caribbea Edmunds 1963: 731–737 , figs 1–5, pl. 1. Type locality: Port Royal , Jamaica.

Berthelinia pseudochloris Kay 1964: 191–193 , fig. 1, pl. 9, figs 1, 4. Type locality: Near Koloa Landing, Koloa, Kaua‘i, Hawaiian Islands.

Tamanovalva babai Burn 1965: 735–736 , fig. 3. Type locality: Point Danger , Torquay, Victoria, Australia.

Tamanovalva fijiensis Burn 1966: 54–55 , pls. 15–19. Type locality: Nukulau Island , Viti Levu, Fiji.

Berthelinia ganapatii Sarma 1975: 16–20 , figs 6–13, 28–29. Type locality: Visakhapatnam , India.

Berthelinia oaltairensis Sarma 1975: 20–21 , figs 23–27, 30. Type locality: Visakhapatnam , India.

Berthelinia rotnesti Jensen 1993: 209–214 , figs 1–4, 5A, 6A. Type locality: Rotnest Island , Western Australia.

Berthelinia daroini Jensen 1997a: 170–175 , figs 6–9. Type locality: Lee Point , Darwin, Australia.

Berthelinia singaporensis Jensen 2015: 233–235 , figs 1F, 5D, E, 6, 7. Type locality: Chek Jawa , Singapore.

EdenTellina schlumbergeri ( Dautzenberg, 1895)

Berthelinia schlumbergeri Dautzenberg 1895: 37–38 , figs A, B. Type locality: Nosibé [= Nosy Be], Madagascar.

Type material

Untraceable, not found in the Royal Belgian Institute of Natural Sciences or in the MNHN .

Remarks

Dautzenberg (1895) described Berthelinia schlumbergeri Dautzenberg, 1895 based on a single right valve dredged from sand in Nosy Be, Madagascar. Te very small shell (0.6 mm long) had the protoconch atached and was illustrated ( Dautzenberg 1895: figs A, B). Based on the size of the teleoconch in relationship to the protoconch, it appears to be a juvenile ( Dautzenberg 1895). Dautzenberg (1895) described the shell as uniformly white, oval, slightly trapezoid, with a rounded anterior end shorter than the posterior end. Te holotype is untraceable, and the limited description of the animal does not allow for a reliable identification of this species.

Ganapati and Sarma (1972) reported juvenile shell specimens from the Andaman Islands as B. schlumbergeri . Ganapati and Sarma (1972) also indicated that these shells were similar to the Madagascar specimen described by Dautzenberg (1895) but recognized that their species could not be determined until more material of fully grown individuals became available. In a later paper, Sarma (1975) reported two new species of Berthelinia from mainland India but made no reference to B. schlumbergeri . Gosliner (1987) and Ono (1999) reported and illustrated photographs of specimens identified as B. schlumbergeri from Sodwana Bay, South Africa and Okinawa, Japan, respectively. Both photographs show green animals with some white spots on the head and neck, white rhinophoral tips, a green mantle, with the edge of the shell surrounded by alternating white and dark bands. Gosliner (1987) confirmed that his specimens from South Africa fed on Caulerpa racemosa (Forsskål) J. Agardh, 1873. Te morphological characteristics of B. schlumbergeri are consistent with those of E. pseudochloris here examined, a species that also feeds on C. racemosa and has planktotrophic development. Terefore, we regard the records of B. schlumbergeri by Gosliner (1987) and Ono (1999) to be E. pseudochloris . Although it is possible that B. schlumbergeri is an older name for E. pseudochloris , this is impossible to determine with certainty based on the original description.

Because the original description of B. schlumbergeri is based on juvenile specimens and lacks details of the internal anatomy, we are unable to confirm the validity of this species. Terefore, B. schlumbergeri is here regarded as a nomen dubium until more information becomes available.