Julia Gould, 1862

Genus Julia Gould, 1862 View in CoL

Julia Gould 1862: 283 View in CoL . Type species: Julia exquisita Gould, 1862 View in CoL , by monotypy.

Prasina Deshayes 1863: 25–29 View in CoL . Type species: Prasina borbonica Deshayes, 1863 View in CoL , by monotypy.

Parasina Habe 1951: 122 [error for Prasina Deshayes, 1863 ].

Diagnosis

Shell, thick, heavy, opaque, typically coloured; oval in lateral view, cordate in anterior/posterior views; anterior margin rounded, narrowing posteriorly, deeply excavated at umbo, with sharp posterior peripheral margin; shell tallest point near mid-length; valves equal in size; hinge with pronounced condyloid (or cardinal) tooth on lef valve, right valve with fossete-like hinge socket; protoconch on lef valve, towards posterior of shell; adductor muscle scar subcentral; shell typically green, with white, brown, or black spots or lines; gill continues across mid-dorsal line to lef side; heart on lef side near the posterior end of gill; short segment of intestine visible dorsally on surface of digestive gland; mantle cavity extends across mid-dorsal line of shell; radular teeth elongate, blade-shaped, inflated, with row of hair-like denticles along each side; teeth cusps with bifid tips.

Remarks

Carpenter ex. Nutall (1857) introduced the species name Smaragdinella thecaphora Carpenter ( ex. Nutall), 1857 from Mazatlán, Mexico, which constitutes the first description of a species now in the genus Julia . Carpenter (1857) considered this new species a member of the Gastropoda, primarily because he had access to only one valve. However, when describing the apical morphology of the shell, he noted that it looked remarkably like the ligamental cavity of Anatinella Sowerby G. B. II., 1833 ( Bivalvia).

Gould (1862) described the genus Julia based on the single species Julia exquisita Gould, 1862 , the type species by monotypy. Although Gould (1862) unequivocally included Julia in Bivalvia, he was unsure of the taxonomic placement within this group and discussed its affinities with other bivalve genera, including Vulsella Röding, 1798 [Family Pteriidae Gray, 1847 (1820)], Pedum Bruguière, 1792 (Family Pectinidae Rafinesque, 1815 ), or even members of the family Veneridae Rafinesque, 1815 . However, Gould (1862) also recognized the affinities between Julia and heterobranch sea slugs, by indicating, ‘A beautiful litle shell, colored like Smaragdinella A. Adams, 1848 from the same islands. Te sudden and profound depression in front of the beaks is quite striking, and thus produces a very pointed somewhat upturned anterior end. A single valve looks much like some of the Bullidae , Chelidonura , for instance’. Gould’s (1862) short description of Julia in Latin summarizes the main diagnostic traits, which are consistent with the modern usage of the name.

Deshayes (1863) introduced the genus name Prasina for the species Prasina borbonica Deshayes, 1863 , the type species by monotypy, collected in Réunion, Indian Ocean. Deshayes (1863) examined a series of single valves collected by Louis Maillard, and because of their green colour, brilliant internal surface, and shell projection, initially concluded they belonged to the genus Smaragdinella . However, by assembling the shells together, Deshayes (1863) realized they were bivalved, regular and symmetrical. Although Deshayes (1863) found the external characteristics of these shells peculiar, he afforded other traits in the interior of the valves ‘much greater importance’, such as the unique shape of the hinge, the insertion of the lunula, and the position of the muscle scars. Tus, Deshayes (1863) introduced the new genus name Prasina for these shells, but as in the case of Gould (1862) and Julia, Deshayes (1863) was unsure of the taxonomic placement of Prasina . Deshayes (1863) proposed that Prasina had intermediate characteristics between the monomyarians (bivalves with a single posterior adductor muscle) and the dimyarians (bivalves with two adductor muscles, one anterior one posterior), but proposed that Prasina was closer to the family Mytilidae Rafinesque, 1815 , of which it could constitute a subfamily. Prophetically, Deshayes (1863) suggested this species could perhaps be, ‘destined to play a more important role, for it may be that the animal offers in its organization facts of greater zoological value than the shell’, and hoped that this small shell would be collected and observed alive. Two additional species of Juliidae were described in the genus Prasina , Prasina cornuta De Folin in De Folin and Périer (1868) (Recent, Mauritius) and Prasina lecointreae Dollfus & Dautzenberg, 1901 (Miocene, Touraine, France).

Semper (1865) was the first to note the similarities between Julia and Prasina , indicating that it was nearly impossible to separate these two genera. E. A. Smith (1885) examined shells of J. exquisita from the Hawaiian Islands and introduced the family name Juliidae for it, although without a taxonomic placement beyond confirming its membership in Bivalvia. One year later, Fischer (1886) formally considered Julia as a subgenus of Prasina and suggested that Berthelinia Crosse, 1875 could also belong to the Prasinidae or Aviculidae Goldfuss, 1820 [= Pteriidae ]. Fischer (1886) also discussed the similarities between Prasinidae , which he considered to be bivalves, and Mytilidae .

E. A. Smith (1885) placed P. borbonica in the synonymy of J. exquisita without further explanation, and Dall (1898) formally synonymized these two genera. Some authors maintained Prasina as a synonym of Julia but considered J. borbonica as a distinct species and pointed out that specimens examined by E. A. Smith (1885) from the Hawaiian Islands belonged to J. borbonica ( Beets 1944, 1949; Howard 1951, Boetger 1962). Other authors agreed to maintain Prasina as a synonym of Julia (e.g. Kay 1968, Kawaguti and Yamasu 1982). Kay (1968) went further and indicated that all Julia shells she examined from the Indian and Pacific Oceans fell within the range of variation of the Hawaiian specimens and suggested that J. japonica and J. equatorialis might represent geographical subspecies.

Kawaguti and Baba (1959) described the first live specimens of Juliidae , which they placed in the Sacoglossa ( Gastropoda) (see remarks on Edentellina ). However, these authors did not immediately make a connection between their newly discovered species and the extensive Recent and fossil literature on this group ( Cox and Rees 1960, Keen 1960b). Keen (1960b) suggested that when specimens of Julia were found alive, they would prove to be gastropods. Two years later, Kay (1962b) reported the first known live animals within the genus Julia , confirming that they belonged unequivocally to Sacoglossa ( Gastropoda).

Additional Recent species of Julia have been described from Japan: Julia japonica Kuroda & Habe, 1951 [also reported from Pleistocene deposits ( Mimoto 1984)], Julia zebra Kawaguti, 1981 , Julia mishimaensis Kawaguti & Yamasu, 1982 , and an unnamed species from Okinawa ( Mizofuchi and Yamasu 1987); India: Julia burni Sarma, 1975 ; and the Eastern Pacific: Julia equatorialis Pilsbry & Olsson, 1944 . Te genus name Julia has also been widely applied to fossil species, including Julia floridana Dall, 1898 (Oligocene, Florida), Julia girondica Cosssman & Peyrot ( ex. Benoist), 1914 (Miocene, Nouvelle-Aquitaine, France), Julia douvillei Cosssman & Peyrot, 1914 {Oligocene, Nouvelle-Aquitaine, France, tentatively assigned to the Helvetian Stage [= Serravallian] in the original description, but subsequently re-assigned to the Late Oligocene by Schneider et al. (2008)}, Julia gardnerae Woodring, 1925 (Miocene, Jamaica), and Julia borneensis Boetger, 1962 (Late Miocene, East Borneo).

Based on the molecular analyses presented here, Julia is clearly distinct from other Juliidae genera described to date, and therefore is considered valid. However, the geometric morphometrics analysis recovered substantial morphological diversity that will be examined in more detail in a separate monograph. Several species regarded as Julia herein cluster in different groups (clusters 1–3; Fig. 3), and it is particularly noteworthy that J. japonica and J. borbonica (cluster 1; Fig. 3) are substantially distant from the rest of Julia . In this study we regard J. borbonica as a synonym of J. exquisita (see remarks on J. exquisita ), which is also highly variable morphologically and represented in two different groups of the PCA. Unfortunately, we did not have access to material of J. japonica suitable for molecular analysis to determine its phylogenetic placement. Additionally, representatives of the fossil genus Candinia are clustered with other members of Julia in the PCA, casting doubt on the validity of the former genus. Further work is necessary to resolve these outstanding issues. Currently, Julia includes Recent and fossil species, which are listed below in chronological order.

Species list

Smaragdinella thecaphora Carpenter ( ex. Nutall) 1857: 533. Type locality: Mazatlán , Mexico.

Julia exquisita Gould 1862: 284 View in CoL . Type locality: Sandwich Islands [= Hawaiian Islands].

Prasina borbonica Deshayes 1863: 29 View in CoL , pl. 4, figs 4–8. Type locality: Réunion.

Prasina cornuta De Folin in De Folin and Périer 1868 [1867– 1872]: 83–84, pl. 9, fig. 7. Type locality: Île Maurice [= Mauritius] .

† Julia floridana Dall 1898: 811 View in CoL , pl. 35, figs 1–3. Type locality: Chipola River , Florida (Early Miocene) .

† Prasina lecointreae Dollfus and Dautzenberg 1901: 271 View in CoL . Type locality: Ferrière-Larçon , France (Middle Miocene) .

† Julia girondica Cosssman & Peyrot View in CoL ( ex. Benoist) 1914: 62–63, pl. 12, figs 19–22. Type locality: Villandraut , France (Early Miocene) .

† Julia douvillei Cosssman and Peyrot 1914: 63–65 View in CoL , pl. 12, figs 30–32. Type locality: Peyrehorade , France (Late Oligocene) .

Julia equatorialis Pilsbry and Olsson 1944: 86–87 View in CoL , pl. 9, figs 10–11. Type locality: Caleto Sal , north of Mancora, Peru.

† Julia gardnerae Woodring 1925: 87–88 View in CoL , pl. 10, figs 15–16. Type locality: Bowden , Jamaica (Middle Miocene) .

Julia japonica Kuroda and Habe 1951: 86 View in CoL . Type locality: Nada , Wakayama Prefecture, Japan.

† Julia borneensis Boetger 1962: 422–423 View in CoL , fig. 3. Type locality: Gunung Mendong, East Borneo (Late Miocene).

† Julia borbonica erythraea Selli 1973: 201–203 , pl. 30, fig. 8A–C. Type locality: Massawa, Erytraea (Pleistocene).

Julia burni Sarma 1975: 12–15 View in CoL , figs 1–5. Type locality: Port Blair, Andaman Islands.

Julia zebra Kawaguti 1981: 9–13 View in CoL , figs 1A, 2–4. Type locality: Mishima , Hagi City and Tsunoshima, Yamaguchi Prefecture, Ishigaki Island , Okinawa Prefecture, Japan .

Julia mishimaensis Kawaguti & Yamasu 1982: 29–31 View in CoL , figs 1–4. Type locality: Tsunoshima , Yamaguchi Prefecture and Ishigaki Island , Okinawa Prefecture, Japan .

In this study, three additional, probably undescribed, species are recognized. As mentioned above, the taxonomy of species of Julia View in CoL and the formal description of these new species will be addressed in a separate monograph.

Genus Candinia Le Renard, Sabelli & Taviani, 1996 View in CoL

† Candinia Le Renard, Sabelli & Taviani 1996: 231–232 View in CoL .

Type species: Candinia pliocaenica Le Renard, Sabelli & Taviani, 1996 , by original designation.

Diagnosis

Shell thick, heavy, oval-trigonal in lateral view, cordate in anterior/posterior views; anterior margin rounded, narrowing abruptly posteriorly into sharp triangular margin; shell tallest point near anterior end; right valve larger than lef valve; hinge with anterior, posterior parts interrupted beneath apex, condyloid (or cardinal) tooth on right valve, lef valve with fossete-like socket; protoconch on lef valve, towards posterior third of shell; adductor muscle scar subcentral.

Remarks

Le Renard et al. (1996) introduced the genus Candinia Le Renard, Sabelli & Taviani, 1996 based on the new species Candinia pliocaenica Le Renard, Sabelli & Taviani, 1996 from the Pliocene of Italy. Le Renard et al. (1996) included Candinia in the subfamily Juliinae and indicated that Candinia is distinguishable from Julia by differences in shell hinge morphology. Le Renard et al. (1996) also suggested that Berthelinia krachi Bałuk & Jakubowski, 1968 , a Miocene species from Poland, is also a member of Candinia . Subsequently, Schneider et al. (2008) described another species of Candinia , Candinia lakoniae Schneider, Hochleitner & Janssen, 2008 , from the Pliocene of Greece. In the PCA presented here ( Fig. 3), members of Berthelinia krachi [= Candinia krachi ] are morphologically indistinguishable from some species of Julia , indicating that these two genera could be synonyms.

Species list

† Berthelinia krachi Bałuk & Jakubowski 1968: 294–297 View in CoL , pl. 1, figs 1–5. Type locality: Korytnica , 24 km SSW of Kielce, Holy Cross Mountains, Poland (Middle Miocene) .

† Candinia pliocaenica Le Renard, Sabelli & Taviani 1996: 232– 234 View in CoL , figs 1–4. Type locality: Pietrafita , Tuscany, Italy (Early Pliocene) .

† Candinia lakoniae Schneider, Hockleitner & Janssen 2008: 83–89 View in CoL , figs 3, 4. Type locality: Glykovrysi , Lakonia, Peloponnese, Greece (Late Pliocene) .

Subfamilp Bertheliniinae Keen View in CoL & A. G. Smith, 1961