Maulstachler

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Maulstachler
Cyclothone microdon

Cyclothone microdon

Systematics
Subclass : Neuflosser (Neopterygii)
Subclass : Real bony fish (Teleostei)
Overcohort : Clupeocephala
Cohort : Euteleosteomorpha
Sub-cohort : Stomiati
Order : Maulstachler
Scientific name
Stomiiformes
Regan , 1909

The Maulstachler (Stomiiformes (= Stomiatiformes Rosen, 1973)), also called big mouths , are an order of the bony fish (Osteichthyes). There are inhabitants of the deep sea , especially tropical or temperate marine regions.

features

Most of the species are black or silver in color, and all, with one exception, have luminous organs. Your swim bladder is usually reduced, your skeleton is light, and your body is high in lipids . Most species are small, not even 10 cm in length. The smallest species are 1.5 cm long, the largest half a meter. William Beebe reported that there were mouth-spikes six feet long, which he described as Bathysphaera intacta , but specimens of this size were never caught.

Many of them have a bizarre appearance, luminous organs in different parts of the body and huge fangs in large, deeply split mouths that reach far behind the eyes. The color of the whiskers is mostly dark brown or black, species of the bristle mouths (Gonostomatidae) are often silvery. The luminous organs are unique among all Teleostei and have a wall of flat connective tissue cells in which guanine platelets are embedded and which are covered on the outside by a layer of pigment. The guanine platelets act as reflectors. In the light organs are the photocytes, light-producing cells that have a very strongly developed endoplasmic reticulum , and gland cells that may have a function as a filter. Muzzle spikes produce their own luciferin . The glow is not generated here by bacteria such as B. with the lantern bearers (Anomalopidae). A total of three types of luminous organs can be distinguished. In the Alpha type, the luminous organs are arranged in rows that run perpendicular to the longitudinal axis of the luminous organs. In the Beta type, the light organs are arranged around a central cavity, which sometimes has an opening to the outside. The gamma-type luminous organs are arranged in a circle around a center. There are also six other Teleostei groups in numerous species that do not get their luminosity from bacteria, but their morphology is always different from those of the Maulstacher.

The teeth can be folded back. They rotate around an axis at the front base of the tooth. There they are connected to the base via mineralized connective tissue, on the back only by connective tissue. Both maxillary and premaxillary are dentate. Often the Maulstachler have a barb on the lower jaw. The eyes are often protruding telescopic eyes, those of the larvae often perched on stalks. Many species do not have scales; if they are present, they are round scales that easily fall off. The pectoral fins as well as the dorsal fin and adipose fin are missing in many species. If there are pectoral fins, they are set deep, the pelvic fins have four to nine fin rays . The swim bladder has no pneumatic duct or is completely absent. If it is present, there is a rete mirabile at its rear end , a network of the finest arteries that are used for gas exchange. In almost all the other Teleostei, with the exception of a few mucous head and thornfish species , the rete mirabile is arranged at the front end of the swim bladder or in the middle. The number of Branchiostegal rays is between 5 and 24, the posterior ones are greatly enlarged, some are articulated with the ventral hypohyalen, other bones of the Branchiostegal apparatus.

Way of life

In most cases, mouth spines live meso- and bathypelagic , i.e. at depths of 200 to 4000 meters. Many are among the most common marine fish. In particular, the genera Cyclothone from the bristle-mouthed family and Vinciguerria from the luminous fish family are repeatedly named as the species of fish with the greatest number of individuals, and many ichthyologists assume that they make more individual specimens than all other vertebrate genera on earth and that their total mass is greater than that of all other fish species. Other species and genera are apparently rare and have only been rarely caught ( Sonoda , Rhadinesthes decimus , Araiophos eastropas ). Muzzle spikes are carnivorous and mainly eat crustaceans and smaller fish. They themselves are an important source of food for marine predatory fish and marine mammals .

External system

The Maulstachler were usually assigned as a basal group to the Neoteleostei , the modern bony fish. However, recent studies come to the conclusion that they are outside the Neoteleostei and are the sister group of the smelt-like (Osmeriformes), a bony fish order whose members live mainly in cool and temperate regions in brackish and fresh water.

The following cladogram shows the systematic position of the Maulstachler as a sister group of the smelt-like:

  Euteleosteomorpha  

 Lepidogalaxii


   
  Protacanthopterygii  

 Golden salmon (Argentiniformes)


   

 Galaxies (Galaxiiformes)


   

 Pike-like (Esociformes)


   

 Salmonid fish  (Salmoniformes)





   
  Stomiati  

 Smelt-like (Osmeriformes)


   

 Maulstachler (Stomiiformes)



   

 Neoteleostei





Template: Klade / Maintenance / Style

Internal system

The internal systematics of the Maulstachler is still very uncertain, especially the luminous fish (Phosichthyidae) are considered paraphyletic . In total there are about 53 genera and 420 species in two suborders and four families:

Silver hatchet ( Argyropelecus olfersii )

Fossil record

The reliable fossil record of the order goes back to the Eocene . Numerous muzzle fossils are also known from the Miocene . Some of them are assigned to genera that still exist today. The Cretaceous genus Idrissa may be the oldest known fossil of the mouth-spined. However, this assignment is problematic and controversial.

literature

  • Shannon Colleen DeVaney: Interrelationships of Fishes of the Order Stomiiformes. Dissertation, online (PDF; 6.6 MB)
  • Kurt Fiedler: Textbook of Special Zoology, Volume II, Part 2: Fish . Gustav Fischer Verlag Jena, 1991, ISBN 3-334-00339-6
  • Joseph S. Nelson : Fishes of the World , John Wiley & Sons, 2006, ISBN 0-471-25031-7
  • Wilfried Westheide & Reinhard Rieger: Special Zoology Part 2: Vertebrae and Skull Animals , 1st edition, Spectrum Akademischer Verlag Heidelberg • Berlin, 2004, ISBN 3-8274-0307-3
  • EO Wiley & G. David Johnson: A teleost classification based on monophyletic groups. in Joseph S. Nelson, Hans-Peter Schultze & Mark VH Wilson: Origin and Phylogenetic Interrelationships of Teleosts. 2010, Verlag Dr. Friedrich Pfeil, Munich, ISBN 978-3-89937-107-9 .

Individual evidence

  1. ^ López, JA, WJ Chen, & G. Ortí. 2004. Esociform phylogeny . Copeia, 2004 (3): 449-464. Abstract
  2. ↑ Chenghong Li, Guoqing Lu & Guillermo Place: Optimal Data Partitioning and a Test Case for Ray-Finned Fishes (Actinopterygii) Based on Ten Nuclear Loci. Syst. Biol. 57 (4): 519-539, 2008 doi : 10.1080 / 10635150802206883
  3. ↑ Jun Li, Rong Xia, RM McDowall, J. Andrés López, Guangchun Lei, Cuizhang Fu: Phylogenetic position of the enigmatic Lepidogalaxias salamandroides with comment on the orders of lower euteleostean fishes. Molecular Phylogenetics and Evolution, Volume 57, Issue 2, November 2010, Pages 932-936 doi : 10.1016 / j.ympev.2010.07.016
  4. ↑ Ricardo Betancur-R, Edward O. Wiley, Gloria Arratia, Arturo Acero, Nicolas Bailly, Masaki Miya, Guillaume Lecointre and Guillermo Ortí: Phylogenetic classification of bony fishes . BMC Evolutionary Biology, BMC series - July 2017, DOI: 10.1186 / s12862-017-0958-3
  5. ^ Karl Albert Frickhinger: Fossil Atlas Fish , Mergus-Verlag, Melle, 1999, ISBN 3-88244-018-X

Web links

Commons : Maulstachler  - Collection of images, videos and audio files