identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
03E587A0FFC1FFD6FE88FEB8DAE8F8DB.text	03E587A0FFC1FFD6FE88FEB8DAE8F8DB.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Hiatella Bosc 1801	<div><p>Hiatella Bosc, 1801</p><p>Type: Hiatella monoperta Bosc, 1801 (by subsequent designation).</p></div>	https://treatment.plazi.org/id/03E587A0FFC1FFD6FE88FEB8DAE8F8DB	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zelaya, Diego G.;Güller, Marina	Zelaya, Diego G., Güller, Marina (2023): Decrypting the feared genus Hiatella (Bivalvia): South American species. Zoological Journal of the Linnean Society 199 (4): 882-905, DOI: 10.1093/zoolinnean/zlad064, URL: http://dx.doi.org/10.1093/zoolinnean/zlad064
03E587A0FFC1FFD9FF32FF30D8C9FD50.text	03E587A0FFC1FFD9FF32FF30D8C9FD50.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Hiatella meridionalis (d'Orbigny 1846)	<div><p>Hiatella meridionalis (d’Orbigny, 1846)</p><p>(Figs 3A–L, 4, 5, 6A, B, G, J, 7F, G)</p><p>Saxicava meriodionalis d’Orbigny, 1846: 521, pl. 81, figs 21, 22.</p><p>Saxicava chilensis Hupé, 1854: 379; Hupé 1858: pl. 8, figs 7, 7a; Rochebrune and Mabille 1889: H101.</p><p>Saxicava antarctica: Martens and Pfeffer 1886: 113–114, pl. 4, fig. 2 (not Philippi, 1845).</p><p>Saxicava lebruni Mabille and Rochebrune in Rochebrune and Mabille, 1889: H101–H102.</p><p>Saxicava mollis Mabille and Rochebrune in Rochebrune and Mabille, 1889: H102–H103.</p><p>Saxicava arctica var. antarctica: Melvill and Standen 1907: 151 (in part) (not Saxicava antarctica Philippi, 1845).</p><p>Saxicava subantarctica Preston, 1913: 223, fig. 12.</p><p>Saxicava solida: Carcelles 1944: 293–294, pl. 13, fig. 107; Carcelles 1950: 82, pl. 5, fig. 91 (not Sowerby I, 1834).</p><p>Hiatella meridionalis: Zelaya 2005: 117; Simone and Penchaszadeh 2008: fig. 18 (only).</p><p>Hiatella A: Laakkonen et al. 2015: 389.</p><p>Type localities: Îles Malouines (= Malvinas / Falkland Islands) ( Saxicava meridionalis); Calbuco, [41°46 ʹ S], Chile ( Saxicava chilensis); Baie Orange [= Bahia Orange] ( Saxicava lebruni; Saxicava mollis); [Malvinas]/ Falkland Islands ( Saxicava subantarctica).</p><p>Material examined: Lectotype of Saxicava meridionalis (NHMUK 1854.12.4.772); two syntypes of Saxicava lebruni (MNHN-IM-2000-31626); one syntype of Saxicava mollis (MNHN-IM-2000-31625); lectotype of Saxicava subantarctica (designated herein: RBINS MT 753); and 94 additional lots (Supporting Information, ESM 1).</p><p>Description: Shell ≤ 61.0 mm L, rectangular to ovate, longer than high, compressed to slightly inflated, with the maximum width at about the posterior third of shell length; thin to moderately solid (Figs 3A–L, 4). Subequivalve in smaller specimens, slightly to markedly inequivalve in larger specimens, with one of the valves (either the right or the less) wider and larger than the other; larger valve overlapping ventrally over the opposite valve. Posterior end of shell greatly projected; anterior end moderately projected. Posterior area of shell narrow, usually flat, sometimes slightly sunken, ill defined. Posterior and ventral gaps between valves narrow. Anterodorsal margin straight, steeply sloping. Anterior margin extremely short, rounded, sometimes indistinct from anterodorsal margin. Ventral margin straight to slightly sinuous. Posterior margin rounded to obliquely flaưened, usually higher than anterior margin. Posterodorsal margin long, convex to straight. Umbo low, wide, evenly rounded; located at anterior third of shell length. Lunule narrow, depressed in smaller specimens, usually indistinct in larger specimens.</p><p>Outer shell surface white, chalky (Figs 3C–L, 4). Dissoconch sculptured with low, narrow, commarginal folds near the umbo, gradually increasing in width, forming cords ventrally. In addition, two thin, low and rounded posterior radial ribs, present, similar to each other in solidness. In specimens of ≤ 16 mm L, radial ribs extending all along dissoconch and bearing hollow spines, which increase in size distally. In larger specimens, radial ribs become less evident, lacking spines distally, and early secreted spines, in the vicinity of the umbo, reduced to their bases. Periostracum thick, pale yellowish to yellowish brown; forming thin periostracal folds; usually lost in older parts of the shell.</p><p>Hinge (Fig. 5): With a single, small cardinal tooth at each valve and a socket to accommodate the tooth of the opposite valve. Right valve cardinal high, thin to thick, sharply pointed, ventrally directed. Less valve cardinal elongate, posteroventrally directed, usually narrow, but sometimes strong in larger specimens. Less valve socket anterior to cardinal tooth; right valve socket posterior to cardinal tooth. Teeth present throughout shell ontogeny. Nymph elongate, narrow, delicate. Ligament strong, external, opisthodetic. Pallial sinus deep. Inner shell surface porcellanaceous, white.</p><p>Anatomy (Fig. 6A, B, G, J): Mantle margin fused for most of its length, with a relatively large (anterior) pedal opening and two smaller (posterior) siphonal openings. Suture behind pedal opening extremely short. Anterior and posterior adductor muscles large, the anterior ovoid, the posterior subcircular, somewhat dorsally displaced. Gills low (~40% of shell height), greatly elongate, with the axis almost horizontal; composed of two complete demibranchs at each side; less and right demibranchs posteriorly fused among them and to mantle margin. Outer demibranch uniform in height all along its length. At anterior end, outer demibranch one-third the height of inner demibranch. At anterior half of the gill, ascending lamella of outer demibranch higher than descending lamella, and descending lamella of inner demibranch higher than ascending lamella. At posterior half of the gill inner and outer demibranchs, and ascending and descending lamellae of each demibranch similar in height. Less and right inner demibranchs ventrally connected by ciliary junctions. Foot relatively large, composed of a compressed stalk, a small heel and a markedly projected anterior ‘toe’; base narrow, flat, with byssal groove extending for ~75% of foot sole. Byssus composed of numerous long, narrow, flat byssus threads, arising from a stout byssus seam; each byssus thread bearing a distal adhesive disc. Byssal gland remains functional in adult specimens. Siphons large, fused at the base, distally separated, reddish brown in all their extensions in living specimens. Inhalant siphon slightly wider than the exhalant; both siphons with numerous series of club-shaped papillae surrounding their openings (Fig. 7G). Inhalant siphon retractor muscle longer and stronger than exhalant siphon retractor muscle. Anterior and posterior labial palps triangular, similar in size, with ≤ 15 sorting ridges in a 57-mm-long specimen.</p><p>Habitat: Infaunal on soss sediments (Fig. 7F), sometimes byssally aưached to gravel, boulders or other rocky substrates.</p><p>Distribution: Along the South American coast, from 41°46 ʹ S in the Pacific to 54° S in the Atlantic, including the Magellan Strait, Isla de los Estados, Burdwood Bank, Malvinas / Falkland Islands and South Georgia (Fig. 1A). From 1.5 to 553 m depth.</p><p>Remarks: d’Orbigny (1846) described H. meridionalis from îles Malouines (= Malvinas / Falkland Islands) and ‘côte de la Patagonie’. The total number of specimens he had at hand when describing this species was not indicated by the author. Only one of these lots (the former) appears in the NHM database (‘ NHMUK 1854.12.4.772’), with no other contemporary lots in the collection (T. White, personal communication, June 2022). This lot currently contains six valves, although, according to the museum book register, it was originally composed of only two (broken) valves. None of the valves of this lot corresponds to the specimen figured by d’Orbigny (1846: pl. 81, figs 21, 22). Nevertheless, this issue was surpassed with the lectotype designation by Simone and Penchaszadeh (2008), and the concomitant (although not formally pointed out by the authors) restriction of the type locality to Malvinas / Falkland Islands. The lectotype (Fig. 3C) of 4 mm length closely resembles the specimen figured by d’Orbigny (1846) (here reproduced in Fig. 3A). However, the other specimens studied by Simone and Penchaszadeh (2008), collected as ‘epizoic on … Zygochlamys patagonica (King &amp; Broderip, 1832) [sic] in grounds 90-130 m depth’ from ‘ Argentina, Buenos Aires, off Mar del Plata’, and assigned by these authors to H. meridionalis do not correspond to this species but to a new species of Hiatella, which is described below.</p><p>Preston (1913) described S. subantarctica also from the Malvinas / Falkland Islands. The specimen originally figured by the author (Preston 1913: fig. 12) was located in the collections of the Royal Belgian Institute of Natural Sciences (RBINS MT 753; Figs 4A, 5B). This shell (18.5 mm long) fits within the intraspecific variability here recognized for H. meridionalis and, consequently, is considered a synonym. Taking into account that Preston (1913) did not indicate the total number of specimens he had at hand when describing this species and the fact that he sold his collections to several museums and private collectors from different parts of the world, the figured specimen is here designated as the lectotype (following ICZN recommendation 74B), with the express purpose of fixing the species concept.</p><p>The study of the type material of two of the species described by Mabille and Rochebrune (in Rochebrune and Mabille 1889) from Cape Horn, i.e. S. lebruni (MNHN-IM-2000-31626; Figs 3D, 4E) and S. mollis (MNHN-IM-2000-31625; Fig. 4B), allows us to confirm that these taxa are also synonyms of H. meridionalis, as is also the case for the material identified by Carcelles (1944: fig. 107; 1950: fig. 91) as S. solida (MACN-In 13560) and for some of the specimens reported by Melvill and Standen (1907) as S. arctica var. antarctica (NMS.Z.1921.143.728.4). The original illustration of S. chilensis by Hupé (1858: pl. 8, figs 7, 7a, reproduced herein in Figs 4F, 5C) also fits within our current concept of H. meridionalis . Hiatella meridionalis is also the name to apply to the molecular taxon ‘ Hiatella A’ of our Molecular Study section (see above) and of Laakkonen et al. (2015).</p><p>Hiatella meridionalis is morphologically similar to the Australian H. australis (Lamarck, 1818) [= Saxicava angasi A. Adams, 1865 in Angas 1865] (figured by Blainville 1827: pl. 78, fig. 3 and pl. 80 bis, fig. 4; Brunckhhorst 1998: fig. 8.44A; Lamprell and Healy 1998: 199, fig. 578). This is another largesized species (up to 53.5 mm long), which retains the hinge teeth at a large size (see Brunckhhorst 1998: fig. 8.44B, C). Beu (1971) pointed out that ‘it is possible that South American specimens are conspecific with Hiatella australis ’. However, H. australis has a proportionally shorter and higher shell than H. meridionalis, with a more raised umbo, and the cardinal tooth of the less valve directed anteroventrally (see Brunckhhorst 1998: fig. 8.44C). In addition, H. australis has a different habitat from H. meridionalis, occurring in the intertidal and shallow subtidal zones (Middelfart et al. 2010). Molecular data provide further evidence to recognize these two entities as distinct (Laakkonen et al. 2015; this study).</p><p>Hiatella meridionalis also resembles the Miocene Antarctic specimens reported by Beu and Taviani (2014: fig. 9a–c) as Hiatella cf. antarctica . However, the Recent (Magellanic) specimens have a more projected posterior end of the shell, a more differentiated posterior area, and a smaller and lower umbo than the Antarctic fossil material. Furthermore, Beu and Taviani (2014) mentioned that hinge teeth were not seen in the specimens they studied (including specimens from 6 to 28 mm in length), whereas similar-sized specimens of H. meridionalis show well-developed teeth. In addition, the authors reported Hiatella cf. antarctica aưached to the surface of the pectinid Austrochlamys forticosta Beu and Taviani, 2013, whereas H. meridionalis lives as infaunal.</p></div>	https://treatment.plazi.org/id/03E587A0FFC1FFD9FF32FF30D8C9FD50	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zelaya, Diego G.;Güller, Marina	Zelaya, Diego G., Güller, Marina (2023): Decrypting the feared genus Hiatella (Bivalvia): South American species. Zoological Journal of the Linnean Society 199 (4): 882-905, DOI: 10.1093/zoolinnean/zlad064, URL: http://dx.doi.org/10.1093/zoolinnean/zlad064
03E587A0FFCEFFDCFEE5FABBDB7CFBD8.text	03E587A0FFCEFFDCFEE5FABBDB7CFBD8.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Hiatella umbonata Zelaya and Marina Güller 2023	<div><p>Hiatella umbonata sp.nov.</p><p>(Figs 3M–O, 6C, D, H, K, 7A–E, 8, 9)</p><p>Zoobank LSID: urn:lsid:zoobank.org:act: 7E5C1E17-9183- 4BE1-8618-37FDC8B1C421</p><p>Saxicava arctica var. antarctica: Melvill and Standen 1907: 151 (in part) (not Philippi, 1845).</p><p>Hiatella solida: Branch et al. 1991: 47, 51 (not Saxicava solida Sowerby I, 1834).</p><p>Hiatella sp: Zelaya 2005: 117.</p><p>Hiatella meridionalis: Simone and Penchaszadeh 2008: 119–127 (not fig. 18); Schejter et al. 2010: 63–67 (not Saxicava meriodionalis d’Orbigny, 1846).</p><p>Hiatella O: Güller et al. 2020: 143, fig. 3.</p><p>Type locality: 54°44 ʹ 49″ S, 59°56 ʹ 51″ W, <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-59.947502&amp;materialsCitation.latitude=-54.746944" title="Search Plazi for locations around (long -59.947502/lat -54.746944)">Marine Protected Area</a> Namuncurá I, Burdwood Bank, 177 m depth, B.O. Puerto Deseado, April 2016 .</p><p>Type material: Holotype (MACN-In 44195: H9) and one paratype (MACN-In 44196: H10) from the type locality.</p><p>Etymology: The name derives from the peculiar umbo of this species.</p><p>Additional material examined: 94 lots (Supporting Information, ESM 1).</p><p>Diagnosis: Shell thick, inflated, with anterior end truncated or only slightly projected. Umbo wide, inflated, obliquely truncated, located at or close to anterior end. Outer shell surface with low and wide commarginal folds. Posterior area of shell wide, defined by a well-developed but narrow umbonal ridge. Hinge with teeth throughout the shell ontogeny. Nymph narrow.</p><p>Description: Shell ≤ 23.0 mm long, usually low and rectangular, sometimes high and square or trapezoidal, sometimes greatly distorted; moderately to widely inflated, with the maximum width at about the posterior third of total shell length; very solid (Figs 3M–O, 8). Markedly inequivalve throughout ontogeny: right valve larger and wider than less valve, ventrally overlapping over less valve. Posterior end greatly projected, sometimes curved or recurved; anterior end abbreviated, truncated, rounded or shortly pointed, lower than posterior end. Posterior area of shell wide, depressed to flat; usually defined by a narrow, rounded to keeled umbonal ridge, indistinct in some specimens. Ventral and posterior gapes between valves small. Anterior area usually with a narrow sulcus, running from the umbo to the ventral margin. Anterodorsal margin frequently indistinct from anterior margin; when distinct, straight and steeply sloping obliquely. Anterior margin short, straight to slightly curved. Ventral margin straight to slightly sinuous. Posterior margin high, obliquely straight to widely arched, exceptionally sinuous. Posterodorsal margin long, horizontally straight to markedly arcuated dorsally or ventrally; sometimes with a sinuation interlocking the opposite valve. Umbo prominent, wide, inflated, usually high but sometimes low, obliquely truncated, higher posteriorly than anteriorly; located at or close to anterior end. Right valve umbo larger than less valve umbo. Lunule elongated, depressed. Outer shell surface white, chalky. Dissoconch sculptured with irregularly distributed, low and rounded commarginal folds, increasing in solidness ventrally. Some folds (primary folds) relatively wide; space between primary folds with thinner (secondary) folds. Sometimes dissoconch showing strong growth disruption, giving the shell a gradated appearance. Posterior end with two radial ribs: one of them running from prodissoconch/dissoconch limit to the junction of the posterior and ventral margins (umbonal ridge) and the other to the junction of the dorsal and posterior margins; the laưer weaker than the former. In specimens &lt;6 mm long, the two radial ribs bear hollow spines, which increase in size distally. In larger specimens, spines do not develop, and early formed spines (in the vicinity of the umbo) appear reduced to their bases, resembling tubercles. Periostracum thin, yellowish straw coloured, forming thin periostracal folds.</p><p>Hinge (Fig. 9): With a single, small cardinal tooth at each valve and a small, triangular socket to accommodate the tooth of the opposite valve. Less valve cardinal triangular, pustular to massive, high to low, sharply to bluntly pointed. Right valve cardinal delicate to solid, elongate, ventrally directed, smaller than less cardinal. Less valve socket anterior to cardinal tooth; right valve socket posterior to cardinal tooth. Teeth present throughout ontogeny. Nymph elongate, narrow, delicate. Ligament strong, external, opisthodetic. Pallial sinus deep. Inner shell surface porcellanaceous, white.</p><p>Anatomy (Fig. 6C, D, H, K): Mantle margin fused for most of its length, with a small (anterior) pedal opening and two smaller (posterior) siphonal openings. Suture behind pedal opening large. Anterior and posterior adductor muscles small, subcircular in section, the anterior one anteroventrally located, the posterior dorsally displaced. Gills high (~80% of shell height), composed of two complete demibranchs at each side; less and right demibranchs posteriorly fused among them and to mantle margin. Outer demibranch gradually increasing in size backwards, with the maximum height at about the middle gill length. At anterior end, outer demibranch two-thirds the height of inner demibranch. At anterior half of the gill, ascending lamella of outer demibranch higher than descending lamella, and descending lamella of inner demibranch higher than ascending lamella. At the posterior half of the gill, inner and outer demibranchs, and ascending and descending lamellae of each demibranch, similar in height. Foot minute, composed of a compressed stalk, a small heel and a somewhat projected anterior ‘toe’; base narrow, flat, with byssal groove, extending for ~85% of foot sole. Byssus composed of numerous, narrow and flat byssus threads arising from a stout byssus seam; each byssus thread bearing a distal adhesive disc. Byssal gland functional in adult specimens. Siphons short, fused at the base, distally separated, grey to pinkish in living specimens (Fig. 7A); both with numerous series of club-shaped papillae surrounding their openings. Inhalant siphon retractor muscle longer than exhalant siphon retractor muscle. Anterior and posterior labial palps small, triangular, with ≤ 10 sorting ridges. Gonad well developed in specimens&gt; 8 mm long. Additional anatomical characters for this species were described by Simone and Penchaszadeh (2008: as ‘ Hiatella meridionalis ’).</p><p>Habitat: Seưlement occurs on the hydroid Symplectoscyphus subdichotomus (Kirchenpauer, 1884) (Schejter et al. 2010) . In the northernmost distributional range, adult specimens were found as epibionts on the pectinid Zygochlamys patagonica (King, 1832) (Fig. 7E), the gastropods Fusitriton magellanicus (Röding, 1798) (Fig. 7B) and Trophon sp., and polychaete tubes. In the southernmost distribution range, the species also appears as an epibiont on the hydrozoan Errina antarctica (Gray, 1872) and the kelp Macrocystis pyrifera (Linnaeus) C. Agardh, 1820 . Hiatella umbonata is also found nestling on barnacle shells and sponges (Fig. 7C, D).</p><p>Distribution: Along the South American coast, from 45°27 ʹ 48″ S in the Pacific to the Atlantic coast of Tierra del Fuego; Magellan Strait; Isla de los Estados; Burdwood Bank; and extending northwards along the outer Argentine continental margin to 38°09 ʹ 03″ S. Also present in Prince Edward Islands (Fig. 1B). From 7.6 to 785 m depth.</p><p>Remarks: Hiatella umbonata is widely variable in shell outline, projection of the anterior end, height of the umbo, development of commarginal and radial sculpture and solidness of hinge teeth. This variability is evident not only when considering specimens from different areas but also among specimens from a single site. However, the study of a large series of specimens and the combination of morphological, anatomical and molecular data allow us to confirm that all the variability described above represents the intraspecific variability of a single species.</p><p>Hiatella umbonata resembles H. solida (Sowerby I, 1834) by having elongated shells and anteriorly displaced umbos. The laưer is a species that was based on specimens from ‘Sanctam Elenam’ (= Santa Elena, Ecuador); although the end of the original description reads ‘there are other varieties from Payta and the Isle of Muerte’ (Perú). With the information available so far, it is impossible to determine whether Sowerby’s I (1834) ‘varieties’ correspond to subspecies of the same species he described from Ecuador or a different species. To increase the confusion, Sowerby II (1875, 1884) reported this species as coming from an unknown locality. The original description of H. solida was not accompanied by an illustration. The first illustration was provided by Sowerby II (1875: species 6; subsequently copied by Sowerby II 1884: pl. 471, fig. 12), showing only the outer shell surface. Dell (1964) regarded the figured specimen (34.5 mm long) ‘as the type’ (= lectotype, according to the ICZN Art. 74.5); although alerting that there is no information on the provenance of this material associated with the lot. Photographs of the lectotype (NHMUK 20220347) of this species are reproduced herein (Fig. 10). Hiatella umbonata clearly differs from the lectotype of H. solida by having a more prominent umbo, narrower posterior radial ribs, smaller anterior adductor muscle scars, and the nymph situated close to the umbo instead of posteriorly displaced. Furthermore, all the specimens of H. umbonata studied herein (independently of their size) show hinge teeth and the corresponding depression to accommodate the tooth of the opposite valve, whereas these elements are absent in the lectotype of H. solida .</p><p>Hiatella umbonata also resembles morphologically the Brazilian specimens identified by Narchi(1973) and Domaneschi and Narchi (1998) as H. solida . Although the correct identification of that material deserves further study, the Brazilian specimens differ strikingly from the new species described herein by having two cardinal teeth in the less valve (Narchi 1973), with at least one of the hinge teeth wearing away in larger specimens (Domaneschi and Narchi 1998); a large and ovoid anterior adductor muscle; long and bright orange–yellow siphons; the outer demibranch half the height of the inner demibranch, and the labial palps with 16 ridges. Furthermore, the Brazilian specimens inhabit the intertidal zone, where they are found nestling or boring.</p><p>In the Magellan Region, H. umbonata is frequently found coexisting with H. meridionalis, from which it differs by having a thicker shell, with broader posterior area; shorter anterior end; wider, higher and more anteriorly displaced umbos; and stronger and more irregular commarginal sculpture. Anatomically, H. umbonata differs from H. meridionalis by having smaller adductor muscles. This fact is particularly evident in the case of the anterior adductor muscle, which in H. umbonata is small, subcircular and restricted to the anteroventral part, whereas in H. meridionalis it is large, occupying most of the anterior end, and ovoid, dorsally projected. Another difference arises in the gill, which is higher in H. umbonata than in H. meridionalis (~80% vs. 40% of shell height, respectively), with the outer demibranch reaching the maximum height in the middle of its length, whereas in H. meridionalis the height of the outer demibranch is uniform throughout its length. Furthermore, H. umbonata has a smaller foot, with a less projected anterior region than that of H. meridionalis . All the above-mentioned anatomical differences are evident independently of the size of the specimens considered.</p><p>The morphological and anatomical characteristics recognized herein for H. umbonata are also recognizable in the specimens from off Mar del Plata, Buenos Aires Province, Argentina, identified by Simone and Penchaszadeh (2008) as H. meridionalis . Consequently, these specimens are here reassigned to H. umbonata . The material identified as Hiatella O in the Molecular Study section above, and by Güller et al. (2020), also corresponds to H. umbonata, as is also the case for some of the specimens from Burdwood Bank reported by Melvill and Standen (1907) as S. arctica var. antarctica . The specimens reported by Schejter et al. (2010: as H. meridionalis) and Branch et al. (1991: as H. solida) also seem to correspond to H. umbonata .</p><p>The persistence of hinge teeth in large specimens clearly allows the distinction of H. umbonata from the Northern Hemisphere ‘ H. solida ’, in which the teeth disappear with growth (e.g. Dell 1964).</p></div>	https://treatment.plazi.org/id/03E587A0FFCEFFDCFEE5FABBDB7CFBD8	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zelaya, Diego G.;Güller, Marina	Zelaya, Diego G., Güller, Marina (2023): Decrypting the feared genus Hiatella (Bivalvia): South American species. Zoological Journal of the Linnean Society 199 (4): 882-905, DOI: 10.1093/zoolinnean/zlad064, URL: http://dx.doi.org/10.1093/zoolinnean/zlad064
03E587A0FFCBFFC0FC48FC05D93CF850.text	03E587A0FFCBFFC0FC48FC05D93CF850.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Hiatella barnea (Ihering 1907) Zelaya and Marina Güller 2023	<div><p>Hiatella barnea (Ihering, 1907) comb. nov.</p><p>(Figs 3P, 6E, F, I, L, 7H, 11–13)</p><p>Saxicava carnea (sic) Ihering, 1907: 105 (nomen nudum; listed only).</p><p>Saxicava barnea Ihering, 1907: 325, pl. 14, fig. 96; Ihering 1914: 63.</p><p>Hiatella solida: Carcelles 1953: 222–223, pl. 5, fig. 111; Aldea and Valdovinos 2005: fig. 11I (not Sowerby I, 1834).</p><p>Barnea saxicava Parodiz, 1996: 267.</p><p>Type locality: Camarones [44°48 ʹ S, 65°42 ʹ W, Chubut Province, Argentina] .</p><p>Material examined: Holotype (MACN-Pi N 510); and 37 additional lots (Supporting Information, ESM1).</p><p>Other published records: 37°02 ʹ 55″ S, 73°30 ʹ 41″ W, Isla <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=-73.51139&amp;materialsCitation.latitude=-37.04861" title="Search Plazi for locations around (long -73.51139/lat -37.04861)">Santa María</a> (Aldea and Valdovinos 2005: as H. solida) .</p><p>Description: Shell ≤ 37.5 mm long, narrowly elongate, very inflated, with the maximum width at about the anterior third of total shell length; moderately solid (Fig. 12). Right valve somewhat larger and ventrally overlapping over less valve. Anterior and posterior ends projected. Posterior area of shell narrow, flat, ill defined. Anterior area of shell with a wide, deep sulcus, radiating from the umbo to the ventral margin. Ventral gape very wide throughout ontogeny; posterior gape small. Anterodorsal margin short, sloping straight. Anterior margin short and rounded. Ventral margin deeply sinuated anteriorly at the gape, rounded to flat posteriorly. Posterior margin widely arched to flaưened, higher than anterior margin. Posterodorsal margin horizontal, straight to slightly convex, longer than the anterodorsal margin. Umbo low, wide, evenly rounded; located at about the anterior third of total shell length. Lunule short, wide, sunken.</p><p>Outer shell surface white, chalky (Figs 11, 12). Dissoconch sculptured with strong, regularly distributed commarginal elements, separated by wide interspaces. Commarginal sculpture consisting of low, wide cords near the umbo, gradually narrowing and increasing in height, originating lamellae ventrally. Lamellae deeply sinuated at anterior sulcus, where they also bear short but stout, triangular, ventrally projected scales. In specimens ≤ 5 mm L, two extremely thin radial ribs bearing small, hollow spines extend posteriorly: one of them running from the prodissoconch–dissoconch limit to the junction of posterior and ventral margins, the second to the junction of dorsal and posterior margins. In larger specimens, ribs lack spines distally, and early secreted spines (in the vicinity of the umbo) appear reduced to their bases, appearing as tubercles; the radial ribs are recognizable only by an abrupt change in the orientation of commarginal sculpture. Periostracum thick, yellowish straw coloured to brownish, forming thin periostracal folds.</p><p>Hinge (Fig. 13): Small-sized specimens (≤ 8 mm long) with a delicate, small cardinal tooth at each valve, and the corresponding depression to accommodate the tooth of the opposite valve. Less valve cardinal triangular; depression anterior to cardinal tooth. Right valve cardinal low, peg-like, ventrally directed; depression behind cardinal tooth. Teeth and depressions lost in specimens&gt; 10 mm long, where valve articulation occurs only by means of the ligament. Nymph short but stout, flaring. Ligament opisthodetic. Pallial sinus deep. Inner shell surface porcellanaceous, white.</p><p>Anatomy (Fig. 6E, F, I, L): Mantle margin fused for most of its length, with a small (anterior) pedal opening and two smaller (posterior) siphonal openings. Suture behind pedal opening extremely short. Anterior and posterior adductor muscles large, ovoid in section, the posterior somewhat dorsally displaced.Gills low (~40% of shell height), elongated, with almost horizontal axis; composed of two complete demibranchs at each side; less and right demibranchs posteriorly fused to each other and to mantle margin. Outer demibranch gradually increasing in height backwards, reaching the maximum size at about two-thirds of its total length. At anterior end, outer demibranch one-third the height of inner demibranch. Ascending and descending lamellae of inner demibranch similar in height throughout their length. Outer demibranch rectangular, anteriorly with ascending lamella higher than descending lamella; similar in size posteriorly. Less and right inner demibranchs ventrally connected by ciliary junctions. Foot medium sized, composed of a compressed stalk and a markedly projected anterior ‘toe’. A narrow byssal groove, extending for ~60% of foot sole. Byssus composed of a few, short, flat byssal threads arising from a byssus seam; each byssal thread bearing a distal adhesive disc. Byssal gland remaining functional in adult specimens. Siphons large, fused at the base, distally separated, orange towards the tip in living specimens. Inhalant siphon slightly wider than exhalant siphon; both with numerous series of club-shaped papillae surrounding their openings. Inhalant siphon retractor muscle longer and stronger than exhalant siphon retractor muscle. Anterior and posterior labial palps triangular, similar in size, with ≤ 10 sorting ridges in an 11-mm-long specimen.</p><p>Distribution: Along the South American coast, from 37°02 ʹ 55″ S in the Pacific to 41°44 ʹ S in the Atlantic and Isla de los Estados (Fig. 1C). From 0 to 309 m depth.</p><p>Habitat: Associated with hard substrates.</p><p>Remarks: Until this study, and for&gt; 100 years, H. barnea had remained known only from its original description, based on a single specimen, inferred to have been collected in Camarones ‘á la base de la formation patagonienne’ (Tertiary) (Ihering 1907, 1914). The original description is extremely poor in detail and unsatisfactorily figured, and the species was never redescribed. In addition, the type material had not been located subsequently, a fact that has led authors to consider this taxon as a species of questionable status (Parodiz 1996). To increase the confusion, Ihering (1907: 105) listed the species as Saxicava carnea (indubitably a lapsus calami), and Parodiz (1996: 297), in a revision of the taxa introduced by Ihering, referred to it as Barnea saxicava (instead of Saxicava barnea, the original binomen).</p><p>As part of this study, the holotype of Saxicava barnea was relocated in the palaeoinvertebrate collection of the MACN. It consists of an articulated specimen, with the right valve slightly broken dorsally. It is properly figured here, for the first time (Fig. 11). This specimen is morphologically indistinguishable from present-day specimens collected at the Atlantic and Pacific coasts of Patagonia (Figs 11, 12). Whether H. barnea is a species occurring in Patagonia since the Tertiary or a species from the Present wrongly described from the Tertiary remains uncertain. The exact geological and stratigraphic provenance of the holotype is unknown. Curiously, a well-preserved system of ºuaternary beach, containing several bivalve species, was described from ‘Camarones’ by Zanchetta et al. (2012), although H. barnea was not listed therein. Further palaeontological studies would help to add some precision to the fossil record of this species.</p><p>Hiatella barnea is an easily recognizable species owing to its elongated and low shell outline, broad, rounded and depressed umbos, wide byssal embayment and prominent commarginal lamellae, which project ventrally into scales. Another distinctive character is the loss of hinge teeth (and the corresponding hinge teeth depressions) through the ontogeny. Anatomically, a peculiar characteristic of this species is the presence of similarly high ascending and descending lamellae of the inner demibranch. The small foot and size of the pedal aperture of this species resemble the characteristics found in H. umbonata, whereas the shape and position of the adductor muscles resemble the condition found in H. meridionalis .</p><p>Based on the material studied herein, H. barnea is not a rare species. In fact, it was collected and figured by Carcelles (1953: fig. 111) and Aldea and Valdovinos (2005: fig. 11I), although, in both cases, identified as ‘ H. solida ’. Examination of the above-mentioned lots (MACN-In 9032-3 and MZUC 29034, respectively) allows us to confirm that these specimens correspond to H. barnea .</p></div>	https://treatment.plazi.org/id/03E587A0FFCBFFC0FC48FC05D93CF850	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Plazi	Zelaya, Diego G.;Güller, Marina	Zelaya, Diego G., Güller, Marina (2023): Decrypting the feared genus Hiatella (Bivalvia): South American species. Zoological Journal of the Linnean Society 199 (4): 882-905, DOI: 10.1093/zoolinnean/zlad064, URL: http://dx.doi.org/10.1093/zoolinnean/zlad064
