Ensis macha ( Molina, 1782 )

Giacomino, Sebastián & Signorelli, Javier H., 2021, Systematic redescription of Solen (Ensisolen) tehuelchus and Ensis macha (Bivalvia: Solenoidea) from Argentina, southwestern Atlantic Ocean, Zootaxa 4964 (3), pp. 541-558: 548-550

publication ID

https://doi.org/10.11646/zootaxa.4964.3.6

publication LSID

lsid:zoobank.org:pub:5A0D449C-B9E7-46E8-B297-3572410D6407

persistent identifier

http://treatment.plazi.org/id/03ED87C9-996D-FFEA-FF4C-FE47C91D1D15

treatment provided by

Plazi

scientific name

Ensis macha ( Molina, 1782 )
status

 

Ensis macha ( Molina, 1782)  

( Figures 3 View FIGURE 3 , 4 View FIGURE 4 , 5 View FIGURE 5 )

Solen macha Molina, 1782: 178   , 348— Molina & Molina, 1789: 328; Mawe, 1822: 28; d’Orbigny, 1846: 505; Hupe in Gay, 1854: 369; Sowerby II, 1874 (in Reeve & Sowerby, 1843-1878): 203, pl. 6, fig. 28; Clessin, 1888: 26, pl. 8, fig. 5; Dall, 1909: 274; Melvill & Standen, 1914: 135.

Ensis macha Molina   —Mörch, 1853: 7; Martínez y Sáez, 1869: 6, pl. 1, fig. 1; Bloomer, 1906: 18; Carcelles & Williamson, 1951: 346; Osorio & Bahamonde: 1970, 206; Reid & Osorio, 2000: 137, fig. 5M.

Solen scalprum King, 1832: 335   ; Mörch: 1853, 6; Sowerby II, 1874 (in Reeve & Sowerby, 1843-1878): pl. 3, fig. 12; Doering et al., 1881: 75; Clessin, 1888: 25, pl. 8, fig. 1; Ihering, 1907b: 317; Stuardo, 1969: 229.

? Solen gladiolus Sowerby I, 1839: 153   , pl. 43, fig. 4; Wood & Wood, 1857: 254, pl. 25, fig. 8a–8c; Mörch, 1853: 7; Philippi, 1887: 169, pl. 34, fig. 8.

Ensis luzonicus Dunker, 1862: 421   —Clessin, 1888: 31, pl. 12, fig. 7.

Solen poirieri Mabille & Rochebrune, 1889: 104   — Ihering, 1907b: 406.

Type material: Ensis luzonicus   ( ZMB 108700, holotype, 77 mm) ( Fig. 3A–B View FIGURE 3 ) and Solen poirieri   ( MNHN-IM 2000-31622, syntype) ( Fig. 3C–F View FIGURE 3 ) are the only species for which type material has been found   .

Types for Solen macha   are lacking. Type region is the “Arcipelago di Chiloe” by original notes. Actually, this name refers to Chiloe Island , Chile   .

Solen scalprus   is lacking in the cabinets of NHMUK. The type area was given as “Patagoniae oras Orientalis (Sea Bear Bay)” southwest of Pingüino Island , Santa Cruz province, Argentina  

Solen gladiolus   types are also missing. The species was described from “S. America”.

Other material examined: Chile: Caulin Beach , North Chiloe ( MLP 5354 View Materials , dry, 3 specimens)   ; Ancud, Chiloé Island ( CNP-INV 849, dry, 10 specimens)   ; Punta Arenas, Magellan strait ( CNP-INV, 1302, dry, 20 specimens)   ; Magellan strait ( CNP-INV 295, dry, 15 specimens; 856, dry, 30 specimens; 859, dry, 10 specimens; 861, dry, 10 specimens; 862, dry, 12 specimens)   . Argentina: Río Negro : Punta Villarino, San Antonio Oeste ( MACN 13347 View Materials , dry, 2 specimens)   ; San Antonio Este, port ( MACN 9379 View Materials , dry, 11 specimens)   ; El Sótano, Golfo San Matías ( CNP-INV 294, dry, 10 specimens; 858, dry, 12 specimens; 867, dry, 15 specimens; 871, dry, 20 specimens; 890, dry, 10 specimens; 1351, dry, 10 specimens)   . Chubut: Gulf of San Matías , Puerto Lobos, ( CNP-INV 256, dry, 30 specimens; 257, dry, 30 specimens; MLP 7397 View Materials , wet, 3 specimens)   ; Riacho, Gulf of San José ( MACN 35357 View Materials , dry, 3 specimens; MLP 6747 View Materials , dry, 2 specimens)   ; La Tapera beah, Gulf of San José ( CNP-INV 249, dry, 35 specimens; 250, dry, 12 specimens)   ; de los Pájaros Island , Gulf of San José ( MLP 3748 View Materials , dry, 2 specimens)   ; Lat. 41°04’ South Long. 65°03’ West ( MACN 18396 View Materials , dry, 1 specimen) GoogleMaps   ; Fracasso beach, Gulf of San José ( CNP-INV 231, dry, 50 specimens; 232, dry, 50 specimens)   ; Villarino, Gulf of San José ( CNP-INV 838, dry, 30 specimens; 840, dry, 30 specimens, 277, dry, 15 specimens)   ; Puerto Pirámides ( MLP 4156 View Materials , dry, 1 specimen)   ; Bahía Camarones ( CNP-INV 285, dry, 20 specimens; 843, dry, 20 specimens; 846, dry, 20 specimens; 870, dry, 20 specimens; 877, dry, 20 specimens)   ; Bahía Bustamante ( CNP-INV 1308, dry, more than 50 specimens; MACN 26443 View Materials , dry, 8 specimens)   ; Comodoro Rivadavia ( CNP-INV1307, dry, 30 specimens; MACN 1960 View Materials , dry, 6 specimens; MACN 6583 View Materials , dry, 96 specimens; MLP 2069 View Materials , wet, 6 specimens; MLP 10244 View Materials , dry, 13 specimens)   ; Rada Tilly ( MACN 14441 View Materials , dry, 65 specimens)   ; Gulf of San Jorge , Alsina beach ( CNP-INV276, dry, 10 specimens; 850, dry, 14 specimens; 852, dry, 10 specimens; 876, dry, 20 specimens; 883, dry, 30 specimens; 842, dry, 20 specimens; 851, dry, 25 specimens; 853, dry, 22 specimens; 854, dry, 12 specimens)   . Santa Cruz: del Fondo Bay ( MLP 2702 View Materials , dry, 1 specimen)   ; Caleta Olivia, Golfo San Jorge ( CNP-INV 291, dry, 10 specimens)   ; Mazarredo, Gulf of San Jorge ( CNP-INV 289, dry, 20 specimens)   ; Puerto Deseado ( MACN 29507 View Materials , dry)   ; Punta Buque, Puerto Deseado ( CNP-INV 287, dry, 30 specimens)   ; Puerto San Julián ( CNP-INV 1304, dry, 10 specimens; MLP 1877 View Materials , dry, 20 specimen; MLP 1874 View Materials , dry, 3 specimens)   ; Monte León, NP, ( CNP-INV 277, dry, 20 specimens; 278, dry, 22 specimens)   ; mouth of Río Gallegos ( MLP 1878 View Materials , dry, 11 specimens)   . Tierra del Fuego: Malvinas / Falkland Islands ( MACN 10158 View Materials , dry)   ; Buen Suceso Bay ( MLP 6829 View Materials , dry, 2 specimens)   ; Puerto Roca, Staten Island ( MACN 21986 View Materials , dry, 1 specimen)   ; San Pío Cape ( MACN 23890 View Materials , dry, 1 specimen)   ; Canal del Beagle , Puerto Almanza ( CNP-INV 286, dry, 10 specimens; 845, dry, 10 specimens; 847, dry, 15 specimens)   ; Ushuaia ( MACN 4059 View Materials , dry, 1 specimen; MACN 23607 View Materials , dry, 2 specimens)   .

Diagnosis: Shell up to 211 mm long, anterior end rounded and posterior end almost straight; dorsal margin concave and ventral margin convex; anterior adductor scar bigger than the posterior one, lentiform, elongated, projecting postero-ventrally; posterior adductor oval, close to the dorsal margin.

Description: Shell length up to 211 mm approximately (MACN 10158), equivalve, inequilateral, cylindrical; ( Fig. 4A–D View FIGURE 4 ); anterior end rounded, posterior end slightly straight; umbo anteriorly placed; dorsal margin slightly concave and ventral one moderately convex ( Fig. 4A–B View FIGURE 4 ); external surface smooth or presenting growth lines; brownish to yellowish periostracum, usually eroded ( Fig. 4A–B View FIGURE 4 ); internal surface white to violet ( Fig. 4C–D View FIGURE 4 ).

Anterior adductor muscle scar bigger than the posterior one, lentiform, elongate, projected inside the mantle cavity ( Fig. 4C–D, H View FIGURE 4 ); posterior adductor muscle scar oval, close to the dorsal margin ( Fig. 4C–D View FIGURE 4 ); pallial line elongated, antero-ventrally, postero-ventrally and postero-dorsally projected ( Fig. 4C–D View FIGURE 4 ); pallial sinus shallow ( Fig. 4C–D View FIGURE 4 ).

Hinge plate like genus diagnosis ( Fig. 4E–F View FIGURE 4 ), the horizontally oriented teeth are four to six times longer than the vertically oriented, the teeth of the right valve fitting between the 2 of the left valve; dark ligament, opisthodetic ( Fig. 4G View FIGURE 4 ).

Mantle Cavity Organs. Three mantle folds, pellucid; ctenidia type C(2a) of Atkins (1937), eulamelibranch, formed by two demibranchs, one left and one right, placed across the antero-posterior axis, each demibranch with one inner descending arm and one outer ascending arm, both arms equal in length and width ( Fig. 5A View FIGURE 5 ), food groove positioned on the distal edge of each demibranch ( Fig. 5G View FIGURE 5 ); two pairs of labial palps, large, up to 6 mm of length, slightly longer than wider, inner surface plicate and outer smooth ( Fig. 5F View FIGURE 5 ); foot highly developed, elongated, pedal groove observed ( Fig. 5A, E View FIGURE 5 ); anterior adductor muscle antero-ventrally elongated, lentiform ( Fig. 5C View FIGURE 5 ); posterior adductor muscle smaller, circular ( Fig. 5D View FIGURE 5 ); siphons type B of Yonge (1982) very short, separate, only fused in the basal region, incurrent siphon bigger than the excurrent one, base of both siphons surrounded by three rows/categories of tentacles, the external crown with 23–25 conical, rounded tentacles, the intermediate crown with 26–28 smaller, and the inner crown with the smallest tentacles, surrounding each siphon separately, incurrent siphons with three categories of tentacles on the aperture ring, excurrent siphon without tentacles on the edge of aperture ring ( Fig. 5B View FIGURE 5 ).

Distribution: Specimens of E. macha   from Chiloe, Chile to San Antonio Oeste, Argentina, were examined. However, its distribution range is usually mentioned to the coasts of Peru ( Osorio & Bahamondes 1970; Paredes et al. 2016; Valentich-Scott et al. 2020; Zaixso et al. 2015, among others). This range must be restricted after the genetic studies that revealed two genetic units ( Márquez et al. 2020; Vierna Fernández 2014). The southern unit, distributed from Chiloe in the Pacific to San Antonio Oeste, in the Atlantic, must be attributed to Ensis macha   and the northern unit, from Tubul, Chile to northern Peru to a new species, currently in process of description ( Márquez et al. 2020).

Habitat: shallow waters (5–30 m depth) of muddy and sandy bottoms ( Barón et al. 2004).

Remarks: Solen macha Molina, 1782   , is the original combination proposed by the author on pages 178 and 348 (description) of his “Historia Natural de Chile ”. Many authors included E. macha   in Solen   ( Küster & Clessin 1842 -1889; d’Orbigny 1846; Dall 1909; Hupe in Gay 1854; Mawe 1822; Melvill & Standen 1914; Sowerby II 1874, in Reeve & Sowerby 1843-1878).

Four junior synonyms of Ensis macha   were checked and confirmed. They are Solen scalprus King, 1832   , Solen gladiolus Sowerby I, 1839   , Ensis luzonicus Dunker, 1862   , and Solen poirieri Mabille & Rochebrune, 1889   . Solen scalprus   and S. poirieri   were described based on juvenile specimens. Although type material of Solen scalprus   was not found, its type locality and hinge description confirmed it as a junior synonym of E. macha   . Martínez y Sáez (1869) considered Solen gladiolus   as a junior synonym of E. macha   . The type material has not been found in the NHMUK, but the original description and illustration suggest affinities with Molina’s species. This synonymy is currently open awaiting further analysis.

The status of Solen luzonicus Dunker   as junior synonym of E. macha   is herein confirmed ( Fig. 3A–B View FIGURE 3 ). The records of Solen luzonicus   of authors (non Dunker, 1862), cited from the Indo- Pacific and eastern Pacific ( Bernard et al. 1993; Habe 1964; Liu 2008; Tsuchida & Hayashi 1994) would belong to S. canaliculatus Tchang & Hwang, 1964   (WoRMS 2020). It was G. B. Sowerby II, 1874 (in Reeve & Sowerby 1843-1878) who first synonymized Dunker´s species with E. macha   . Sowerby II stated “It is quite impossible to discover any specific difference between the Patagonian and Philippine shells…” (unpaged, see text of Species 12 of Sowerby II, 1874, in Reeve & Sowerby 1843-1878). In this context, it is probable that the registered type locality of Ensis luzonicus Dunker, 1862   (Luzon Island, Philippines) was erroneous. Solen poirieri   described by Mabille & Rochebrune (in Rochebrune & Mabille 1889) for Orange Bay, Tierra del Fuego, was mentioned by Carcelles (1944) as young specimens of E. macha   . After revising type material from the MNHN, Paris, we confirm this statement ( Fig. 3C–F View FIGURE 3 ).

The specimens identified as E. macha   by Ihering (1907a) from the San Sebastian Islands, Brazil, are beyond their currently confirmed geographic range and could belong to Solen (Ensisolen) tehuelchus   . Material, labelled as Solen scalprum King, 1832   , from MACN (16684; 12017; 11163; 10230; 10689; 635; 9363; 11667) belong to Solen (E.) tehuelchus   . According to Huber (2010), Solen scalprum Gould, 1851   (non King, 1832), is a valid species of Cultellus   ( Pharidae   ) from Singapore.

Comparisons: The results exposed by Atkins (1936) related to Ensis species   are similar to the morphology observed in E. macha   . The fusion of the anterior part of the dorsal edges of the ascending lamellae with the foot were also observed in the South American species. Ensis macha   shows food grooves on the ventral edge and between demibranchs ( Fig. 5G View FIGURE 5 ). This species is the only member of the family Pharidae   in the southwestern Atlantic. Records of this species from Tubul, Chile, to the north in the Pacific coast of South America belong to a new taxon, currently in process of description (Signorelli et al. in prep.). Compared to other Ensis species   , the shell of E. macha   reaches 22 cm in length, but can be considerably broader than E. siliqua ( Linnaeus, 1758) ( Cosel 2009)   . The free portion of the siphons in E. macha   is less prominent than in E. directus ( Conrad, 1843)   and E. ensis ( Linnaeus, 1758)   ( Bloomer 1905b, 1906) and the posterior end is not curved outwards or inwards as in those two species. Related to the musculature, the anterior adductor is more elongate towards the posterior end but less broad, and the posterior adductor is closer to the pallial sinus than in E. ensis ( Bloomer 1906)   . Whereas, compared with E. magnus   , E. macha   has the posterior adductor less elliptical and the anterior adductor less broad. Bloomer (1906) also observed that the fourth aperture in E. macha   is central and longer than in E. ensis   in which it is more posteriorly placed, but placed in a similar position as in E. magnus   . And the tentacles bordering the siphonal apertures are less numerous in E. macha   than in E. ensis ( Bloomer 1906)   .

ZMB

Museum für Naturkunde Berlin (Zoological Collections)

NHMUK

Natural History Museum, London

MLP

Museo de La Plata

Kingdom

Animalia

Phylum

Mollusca

Class

Bivalvia

Order

Adapedonta

Family

Pharidae

Genus

Ensis

Loc

Ensis macha ( Molina, 1782 )

Giacomino, Sebastián & Signorelli, Javier H. 2021
2021
Loc

Solen poirieri Mabille & Rochebrune, 1889: 104

Ihering 1907: 406
Rochebrune, A. T. & Mabille, H. 1889: 104
1889
Loc

Ensis macha

Reid, D. G. & Osorio, C. 2000: 137
Carcelles, A. R. & Williamson, S. I. 1951: 346
Bloomer, H. H. 1906: 18
Saez, F. 1869: 6
1869
Loc

Ensis luzonicus

Dunker, W. 1862: 421
1862
Loc

Solen gladiolus Sowerby I, 1839: 153

Philippi, R. A. 1887: 169
Wood, S. V. & Wood, S. V. 1857: 254
Sowerby, G. B. I. 1839: 153
1839
Loc

Solen scalprum

Stuardo, J. 1969: 229
Ihering 1907: 317
Doering, D. A. & Berg, C. & Holmberg, E. L. 1881: 75
King, P. P. 1832: 335
1832
Loc

Solen macha

Melvill, J. C. & Standen, R. 1914: 135
Dall, W. H. 1909: 274
Mawe, J. 1822: 28
Molina, J. I. & Molina, G. I. 1789: 328
Molina, G. I. 1782: 178
1782