Edentellina chloris, (Dall, 1918)

EdenTellina chloris ( Dall, 1918)

( Figs 4C–F, 5C, D, 9–11)? Scintilla chloris Dall 1918: 5 . Type locality: Magdalena Bay , Baja California Sur, Mexico.

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

Type material

? Scintilla chloris , syntypes, right and lef valve (not from same specimen), 9 mm long (USNM 218179); right valve 9 mm long ( CASIZ 064093).

Berthelinia chloris belvederica , holotype, dry, 8.2 mm long ( CASIZ 064091 ) ; paratypes, four valves 2.3–4 mm long ( CASIZ 064092 ) .

Additional material examined

Pacific Coast of Baja California: East of Punta Estrada at Sail Rock, north entrance of Bahía Magdalena , Baja California Sur, Mexico, 30–31 January 1974, three valves 4–11 mm long, leg. J. McLean ( NHMLA 1974 - 14.9 ) .

Gulf of California: Punta Pelícano , Puerto Peñasco, Sonora, Mexico, 30 March 1979, one specimen 10 mm long (shell), leg. C. J. O’Kelley ( CASIZ 018381 ) . Half a mile south of Rancho Algodones, near Bahía San Carlos, Sonora, Mexico, December 1975, two specimens 8 mm long (shells), isolates JC3A–B, leg. Forrest and Poorman ( NHMLA 186690 ) . Isla San José , Baja California Sur, Mexico, 2 April 1974, 10 specimens 4–9 mm long (shells), leg. G. Sphon ( NHMLA 1974 - 33.1 ) . Bahía Partida , between Isla Partida and Isla del Espiritu Santo, Baja California Sur, Mexico, 10 April 1966, one specimen 7 mm long (shell), leg. J. McLean ( NHMLA 1966 - 28.30 ) ; three valves 6–6.5 mm long, leg. J. McLean ( NHMLA 1966 - 28.31 ) ; four valves, 4–4.5 mm long, leg. J. McLean ( NHMLA 1966 - 28.31 ) . Bahía Candelero , Isla del Espiritu Santo, Baja California Sur, Mexico, 31 August 1960, 10 specimens (dry) 1.5–4.5 mm long, leg. M. Keen & A. G. Smith ( CASIZ 201953 ) ; 1959–60, six specimens (dry) 4–7 mm long, leg. Belveder Science Expedition ( CASIZ 201955 ) ; 18 valves 1–3 mm long ( CASIZ 201951 ) ; two specimens + two valves 1–4 mm long ( CASIZ 201952 ) . Puerto Ballena , Isla del Espiritu Santo, Baja California Sur, Mexico, 19 December 1960, five specimens (dry) 3–6.5 mm long, leg. M. Keen & M. L. Valdez de Adcock ( CASIZ 201954 ) ; one specimen (dry) 3 mm long, leg. Belveder Science Expedition ( CASIZ 201954 ) . Puerto Balandra , Baja California Sur, Mexico, 4 October 1960, 28 specimens (dry) 4–8.5 mm long, leg. A. G. Smith & K. K. Bechtel ( CASIZ 201967 ) ; five specimens (dry) (possible paratypes of B. chloris belvederica ) 3.9–7.5 mm long, leg. A. G. Smith & K. K. Bechtel ( CASIZ 201965 ) ; 17 valves (possible paratypes of B. chloris belvederica ) 1–3 mm long, leg. A. G. Smith & K. K. Bechtel ( CASIZ 201963 ) .

Galapagos Islands: Flamingo Cove, Isla Floreana , Galapagos Islands, Ecuador, 15 March 1971, one specimen 5 mm long (shell), leg. Ameripagos Expedition (stn. 10) ( NHMLA 1971 - 52.14 ) ; 15–16 March 1971, one specimen (dry), 4.5 mm long (shell), leg Ameripagos Expedition (stn. 11) ( NHMLA 1971 - 53.15 ) . Punta Espinosa , Isla Fernandina , Galapagos Islands, Ecuador, 25 January 1972, one shell 9 mm long, leg. R. M. Lease ( Searcher stn. 333) ( NHMLA 1972 - 197.8 ) ; Nov 1992, one specimen 4 mm long (shell), leg. T Gosliner ( CASIZ 087112 ) . Bahía Urbina , Isla Isabela , Galapagos Islands, Ecuador, 1–3 m depth, 24 January 1972, two valves 9 mm long, leg. S. Earle ( NHMLA 1972 - 192.1 ) .

Description

Body elongate, ≤ 10.5 mm in length, completely retractable inside of shell. Body colour vibrant dark green, with minute white speckles throughout ( Fig. 5C, D). Head elongate, with eye spots located on dorsal swelling near centre, surrounded by white pigment. Rhinophores enrolled, green, with small white speckles ofen forming a ring at the apex, cluster of white speckles on dorsal side. Oral tentacles short, green with white speckles on long edge. Foot lighter than rest of animal, with small spots along edge. Mantle visible through shell, vibrant dark green, covered with a few whitish to pale green spots, variable in size; edge surrounded by conspicuous alternating opaque white patches composed of densely arranged speckles. Foot extending to posterior end of shell, forming small triangular projection.

Shell up to 9 mm × 5.6 mm in size, tallest point near centre, widest point near ventral margin; shell shape ovoid, dorsal margin regularly curved, ventral margin more flatened; anterior margin convex, irregularly curved, slightly more flatened dorsally, posterior margin narrowing gradually, forming a nearly triangular, elongate shape, with round end ( Fig. 9G, H). Protoconch on lef valve of teleoconch, ~110 µm long, with 1.5 whorls ( Fig. 9K). Hinge on dorsal margin of shell, formed by flatened, corrugated, nearly straight area, margin on both valves; small, oval condyloid tooth on right valve at posterior end of hinge, and triangular, fossete-like hinge socket on lef valve, at posterior end of hinge ( Fig. 9I, J). Shell translucent, with no visible markings or spots on shell surface, and sof parts of body visible through it ( Fig. 9A–F).

Adductor muscle located closer to anterior end of shell, slightly below widest point of shell ( Fig. 10A), connected to narrow and elongate head retractor muscle. Adductor scar visible on shell ( Fig. 9H). Gill large, occupying almost height of body, posterior to adductor muscle, covering anterior portion of digestive gland. Anterior half of body in preserved specimens with pair of elongate pharyngeal appendages visible between head retractor muscle and gill ( Fig. 10B), connecting to the pharyngeal bulb dorsally ( Fig. 10C). Penis elongate; distal end pointed, with no stylet visible; proximal end wider, with two strong retractor muscles atached, and long, tubular deferent duct ( Fig. 10D).

Radula with 29 teeth in descending limb and 9 fully formed teeth + 1 ghost tooth in ascending limb, in 9-mm-long specimen from Baja California Sur, Mexico ( NHMLA 1974 - 33.1 ) ( Fig. 11A), and with 25 teeth in descending limb and 7 fully formed teeth + 2 ghost teeth in ascending limb, in 8-mm-long specimen from Sonora, Mexico ( NHMLA 186690 ) ( Fig. 11C). Active tooth ~130 μm long, with sharp, pointed tip; blade elongate, with central row of numerous long, delicate denticles; base elongate, slightly curved ( Fig. 11B, D). Ascus containing a rod-shaped pre-radular tooth plus about five intermediate teeth ( Fig. 11C) .

Biology

Keen and A. G. Smith (1961) reported finding living animals of this species in shallow water ( 0–2.5 m depth) on Caulerpa sertularioides (S. G. Gmelin) M. Howe, 1905 and Caulerpa racemosa var. turbinata [= Caulerpa chemnitzia (Esper) J. V. Lamouroux, 1809], which is a member of the Caulerpa racemosa –peltata species complex (see Belton et al. 2014).

Range

Eastern Pacific Ocean: Baja California ( Dall 1918, Keen and A. G. Smith 1961; present paper), Costa Rica ( Camacho-García et al. 2005), and Galapagos Islands ( Sphon and Mulliner 1972; present paper).

Remarks

Dall (1918) introduced the name? Scintilla chloris Dall, 1918 based on two shells collected in Magdalena Bay, Baja California Sur, Mexico. He described the shells as pale green, translucent, with paler rays, the posterior end [anterior] wider, longer, and more rounded than the anterior end [posterior], which was shorter, with a hinge, a single noduliform denticle, and a faint lateral lamella ( Dall 1918). Dall (1918) interpreted the two shells as lef valves and suggested that they could belong to the bivalve genus Scintilla Deshayes, 1856 . Keen and A. G. Smith (1961) examined manuscript illustrations of the type material of this species and additional specimens from the Pacific coast of the Baja California Peninsula and concluded that the two shells examined by Dall (1918) were, in fact, opposite valves. Tis has been corroborated by recent examination of the type material (USNM 218179) ( Fig. 4C, D). Keen and A. G. Smith (1961) placed this species in Berthelinia and described the subspecies B. chloris belvederica based on additional specimens from the Gulf of California coast of Baja California Sur, which were morphologically different from the type material of B. chloris chloris . Specifically, Keen and A. G. Smith (1961) noted that the syntype of B. chloris chloris they examined was larger, more inflated, and had a more prominent lamellar tooth in the hinge than their specimens of B. chloris belvederica . Boetger (1962) considered the differences between B. chloris belvederica and B. chloris chloris to fall within the normal range of variation of a species and therefore regarded them as synonyms. Tis opinion is generally accepted, and more recent records refer to B. chloris belvederica as B. chloris ( Sphon & Mulliner 1972; Camacho-García et al. 2005). We obtained the holotype of B. chloris belvederica ( Fig. 4E, F) and did not find any distinguishing differences between it and B. chloris chloris here examined. Terefore, we consider both to be B. chloris .

Camacho-García et al. (2005) and Behrens et al. (2022) illustrated live animals of B. chloris , which were nearly uniformly green, with white dots concentrated on the rhinophores (forming a longitudinal line) and around the eyes, in addition to faint white patches around the mantle margin, visible through the shell. Photographs of additional specimens ( Fig. 5C, D) are similar but have more white pigment on the mantle, occupying almost the entire periphery of the shell, except for areas interrupted by green pigment, forming a dashed patern.

For this study, we examined specimens from the Eastern Pacific Ocean ( Sonora, Baja California, and Galapagos Islands) matching the original description of B. chloris . Molecular phylogenies and geometric morphometric analyses nest this species within Edentellina and therefore it is here transferred to this genus. Edentellina chloris is similar to E. pseudochloris , but both are morphologically and genetically distinct, thus herein both are regarded as valid.

EdenTellina corallensi s Hedlep, 1920

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

Type material

Edentellina corallensis , syntype, one right valve, 5 mm long ( AM C.27643).

Remarks

Hedley (1920) introduced the name Edentellina corallensis Hedley,1920 forseveralshellspecimenscollectedinQueensland, Australia. Hedley (1920) described the species briefly in the context of its differences from E. typica , commenting that the shell of E. corallensis was more solid, more compressed, and more pointed ‘anteriorly’ [= posteriorly, based on the convention used in the present paper]. Hedley (1920) also described the colour of the shell as pale sulphur yellow. Examination of the syntype of E. corallensis does not reveal any distinctive features consistent with any of the material here examined. Terefore, we are unable to determine the taxonomic status of E. corallensis and regarded it as a nomen inquirendum.