Hiatella
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"Northern rock borer ( Hiatella arctica )" |
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| Scientific name | ||||||||||||
| Hiatella | ||||||||||||
| Daudin in Bosc , 1801 |
Hiatella is a shell - genus from the family of rock drill (Hiatellidae). Housing and way of life are extremely variable, up to now five species have been differentiated by housing morphology. However, the first molecular biological investigations discovered at least 13 species, which, however, cannot be differentiated on the basis of housing features. The oldest representatives of the genus come from the Lower Jura ( Hettangium ).
features
The same-hinged to slightly uneven-hinged, distended and very variable cases are up to 4 centimeters long, but usually only up to two centimeters. The left flap is occasionally a bit smaller and sits in the right flap. The cases are very unequal, the clear, forward curled vertebrae sit near the front end (front third). They are elongated-elliptical / egg-shaped, elongated-rounded-rectangular to elongated-rounded-trapezoidal, occasionally even irregular. They are significantly longer than they are high. The rear dorsal edge rises flat, it is straight, also slightly concave, then convex and merges into the widely rounded or truncated rear edge. The anterior dorsal margin drops steeply, almost vertically. The front edge is tightly rounded, occasionally also pointed or trimmed. The ventral margin is slightly concave, slightly convex or almost straight. The lunula is sunk and well marked. The area is clearly limited. The ligament lies externally and sunk into a longitudinal pit and extends to about a quarter of the dorsal margin as seen from the vertebra. The lock has a single nodular tooth in the right flap and two nodular teeth in the left flap. Posterior teeth are absent. Usually, the teeth in both valves in adults are abraded. The two rounded sphincters are unequal in size, with the posterior sphincter slightly larger than the anterior sphincter. The surface line is deeply indented at the back.
The whitish skin is thick, brittle and rather fragile. The ornamentation consists of irregular ribs and lines parallel to the edge. One or two radial keels may extend from the vertebra to the posterior end. They are usually covered with short hollow thorns in juvenile specimens, which are often abraded in adult specimens. The straw-colored periostracum is membrane-like and persistent, is hardly rubbed off, except in the area of the vertebrae, where the shell is often attacked. The inner surface is white. The inner edge of the case is smooth.
Geographical distribution and habitat
The genus Hiatella occurs in the Atlantic , Arctic, and Eastern Pacific . The species settle from shallow water (less than 10 meters deep) to greater depths (several hundred meters). The animals live pinned to byssus in crevices, under empty shell flaps, stones or open on hard ground. However, you can also mechanically (and chemically?) Drill holes in softer limestone and sandstone and then stay in your cave for life. Only the siphons then protrude from the opening , through which they take in food and breathing oxygen.
Taxonomy
The genre was first published in 1801 by Louis Augustin Guillaume Bosc . However, he attributed it to François-Marie Daudin , so that this must be considered the author of the taxon. The scope and subdivision of the taxon are, however, highly controversial because the species are very variable. So far some authors have assumed only one single recent, cosmopolitan, very variable species, other authors considered at least five recent species to be valid. There are also some fossil species. In 1987 Andrzej Pisera synonymized four fossil species with Hiatella phaseolus from the Middle and Upper Jurassic . Here is the "classic" breakdown of the genre:
- Genus Hiatella Daudin in Bosc, 1801
- Northern rock borer ( Hiatella arctica (Linnaeus, 1767))
- Hiatella arenacea (EA Smith, 1910)
- Hiatella australis (Lamarck, 1818)
- Hiatella azaria (Dall, 1881)
- Common rock borer ( Hiatella rugosa (Linnaeus, 1767))
- † Hiatella phaseolus (Deslongchamps, 1838)
However, recent molecular biological studies show that the previously recognized species cannot be differentiated on the basis of housing features.
The genus Hiatella - a complex of cryptic species
According to the previous (“classic”) view, the northern rock borer ( Hiatella arctica ) is one of two species of the genus Hiatella in the North Atlantic, alongside the common rock borer ( Hiatella rugosa ) . Hiatella arctica is also said to occur in the northern Pacific . There are also three other species in the Pacific.
According to molecular biological investigations by Hanna Laakkonen, Petr Strelkov and Risto Väinölä, however, these five “classic” species form a complex of (at least) 13 molecular biological species that cannot be distinguished by their morphological characteristics ( cryptic species ). Specimens with the same housing morphology were among others. U. to different molecular biological species, specimens with very different housing morphology and the like. U. to the same molecular biological type.
Six of these cryptic species have been found in the North Atlantic and five cryptic species in the northern eastern Pacific. Two other molecular biological species have been found in the eastern South Pacific. These 13 molecular biological species were named Hiatella AM by the authors of the study . The two molecular biological species of the eastern South Pacific were named Hiatella A and B. Restricted to the North Atlantic are Hiatella C, D, E, F, and K. Restricted to the Northern Pacific are Hiatella G, H, I, J, and M. Hiatella L was found in the northwest Atlantic and the northern Pacific.
Hiatella C was only found in the Mediterranean, but Hiatella D also occurs here sympatric . Hiatella F was only found in the Bay of Biscay ; here, too, Hiatella D appears sympatric. In Scotland, Hiatella E occurs predominantly , sympatric next to Hiatella D. In northern Norway and the Barents Sea as well as the Skagerrak and the southeastern Baltic Sea , Hiatella K has been identified, sympatric next to small populations of Hiatella D and Hiatella E. It is possible that two of these molecular biological species are associated with the two Identify Linnaeus species, as the type locality of both Linnaeus species is in Norway. The type locality of Hiatella striata (Fleuriau de Bellevue, 1802) is near La Rochelle (French Biscay coast). The type locality of Hiatella gallicana Lamarck, 1818, is the French Biscay coast.
So far, a reliable correlation of a molecular biological species with a scientific name has not been achieved in any case. In almost all cases, the molecular biological study also fails to answer the question, if the species cannot be distinguished by morphological characteristics, which criteria (ecological, anatomical, reproductive biology) keep the detected molecular biological species genetically separated from one another? Only in the case of Hiatella E ( Scotland and smaller populations in the Skagerrak and Kattegat) is it indicated that it is probably a species that prefers to live in water depths> 10 meters. We simply have to wait for further studies that combine the previous molecular biological data with morphological-anatomical, ecological and reproductive biological data.
Phylogeny
The North Atlantic molecular biological species Hiatella C, D, E and F are more closely related and form a clade. The molecular biological species Hiatella G, H, I, J, K and L, on the other hand, form the other large clade. This means that Hiatella K immigrated from the Pacific to the North Atlantic and subsequently became extinct in the North Pacific. Hiatella L, which occurs jointly in the North Atlantic and North Pacific, also migrated from the North Pacific to the Northwest Atlantic. These two clades form sister groups. The two molecular biological species of the eastern South Pacific, Hiatella A and B, do not form clades, but rather are each basal opposite the two clades or Hiatella A is the sister species of a clade consisting of all other species.
literature
- S. Peter Dance, Rudo von Cosel (arrangement of the German edition): The great book of sea shells. 304 pp., Verlag Eugen Ulmer, Stuttgart, 1977 ISBN 3-8001-7000-0 (p. 274)
- Rudolf Kilias: Lexicon marine mussels and snails. 2nd edition, 340 p., Verlag Eugen Ulmer, Stuttgart 1997 ISBN 3-8001-7332-8 (p. 243)
- Raymond Cecil Moore (Ed.): Treatise on invertebrate paleontology. Mollusca, 6, Part N, Bivalvia 2. XXXVIII S., S.N491-951, New York, 1969 (S.N849).
- Fritz Nordsieck : The European sea shells (Bivalvia). From the Arctic Ocean to Cape Verde, the Mediterranean Sea and the Black Sea. 256 p., Gustav Fischer Verlag, Stuttgart 1969 (p. 147)
- Guido Poppe and Yoshihiro Goto: European Seashells Volume 2 (Scaphopoda, Bivalvia, Cephalopoda) . 221 pp., Verlag Christa Hemmen, Wiesbaden 1993 (2000 unc. Reprint), ISBN 3925919104 (p. 137)
Individual evidence
- ↑ Simon Schneider, Andrzej Kaim: Early Ontogeny of Middle Jurassic Hiatellids from a wood-fall association: implications for phylogeny and palaeoecology of Hiatellidae. Journal of Molluscan Studies, 78: 119-127, 2012. doi : 10.1093 / mollus / eyr048
- ↑ Louis Augustin Guillaume Bosc :: Histoire naturelle des coquilles: contenant leur description, les moeurs des animaux qui les habitent et leurs usages: avec figures dessinées d'après nature. Tom III. Deterville, Paris, 1801 Online at www.biodiversitylibrary.org (p. 120)
- ↑ a b MolluscaBase: Hiatella Bosc, 1801
- ↑ Andrzej Pisera: Boring and nestling organisms from Upper Jurassic coral colonies from northern Poland. Acta Palaeont. Polonica, 32 (1-2): 83-104, 1987 PDF
- ↑ Hanna M. Laakkonen, Petr Strelkov, Risto Väinölä: Molecular lineage diversity and interoceanic biogeographical history in Hiatella (Mollusca, Bivalvia). Zoologica Scripta, 44: 383-402, 2015 doi : 10.1111 / zsc.12105
- ↑ Carl von Linné: Systema naturae, Tom. I. Pars II. Editio duodecima reformata. P. 533–1327, Stockholm / Holmia, Salvius, 1767 Online at www.biodiversitylibrary.org (p. 1113 Mya arctica , p. 1156 Mytilus rugosus )
- ↑ Louis Benjamin Fleuriau de Bellevue : Mémoire sur quelques nouveaux genres de mollusques et vers lithophages, et sur les facultés qu'ont ces animaux de percer le rochers. Journal de Physique, de Chimie, d'Histoire Naturelle et des Arts, 54: 345-369, Paris 1802. Online at www.biodiversitylibrary.org (p. 349)