Lomis hirta
| Lomis hirta | ||||||||||||
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Lomis hirta |
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| Systematics | ||||||||||||
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| Scientific name of the superfamily | ||||||||||||
| Lomisoidea | ||||||||||||
| Bouvier , 1895 | ||||||||||||
| Scientific name of the family | ||||||||||||
| Lomisidae | ||||||||||||
| Bouvier, 1895 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Lomis | ||||||||||||
| H. Milne Edwards , 1837 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Lomis hirta | ||||||||||||
| ( Lamarck , 1818) |
Lomis hirta is a central cancer and the only species in the superfamily of the Lomisoidea . It becomes about 3 centimeters wide and isnativeto the south coast of Australia and the north coast of Tasmania .
features
External morphology
Lomis hirta has a broad, very flat and symmetrical build. It appears almost rectangular, with a maximum carapace width and length of 3 centimeters. Their claws are wide and flat, opening horizontally rather than vertically, which helps in the flat appearance of this cancer. The color of Lomis hirta is grayish-brown, the entire body is covered by hair ( setae ), which gives it a rather brown appearance. The antennae and mouthparts are distinctly blue in color.
Individual areas of the carapace are not delimited, it is completely covered by tufts of hair. The rostrum is small and triangular. There are no clearly defined marginal areas (ocular scales) at the eye sockets. The base of the antennas (antennal peduncle) has six sub-areas and thus an excess segmentation compared to other anomuric crabs. The flagella of the antennae are thick and have long, paired bristles. There is a sting on the epistome . The third pair of maxillipedas is pediform. Lomis hirta has 14 gills (Trichobranchia) on each side. The abdomen is symmetrical and has calcified tergites . It is easily struck under the cephalothorax. The second tergite is visible in the dorsal view.
In addition to the scissors on the first striding leg , there are also small scissors on the second to fourth pairs of legs. As with all Anomura, the fifth pair of legs is comparatively small and modified to make cleaning legs. In males, the first two pairs of are swimming legs as gonopods present, the missing third to fifth pair or has atrophied. All five pairs of swimming legs are present in females. The uropods are stunted in males, the telson is a relatively small, calcified plate in both sexes. The sexual dimorphism in the uropods is the characteristic apomorphism of Lomis hirta .
Internal morphology
Digestive system: The stomach (chewing stomach + pylorus) of L. hirta sits dorsally in the front area of the cephalothorax. Different muscles insert into the more calcified areas of the stomach, the gastric ossicles. Starting from the pylorus, the tubular (end) intestine moves into the telson or anus. A short pair of cecae arises dorsally at the transition between pylorus and (end) intestine and an unpaired cecum arises laterally on the left in the fifth pleon segment. The unpaired rear (posterior) cecum runs forward (anterior) and rolls up in the second pleonic segment. The hepatopancreas fills most of the cephalothorax and parts of the pleon and consists of two lobes of tubular diverticula that are connected to the pylorus by a common duct. The underside of the stomach is encompassed by the hepatopancreas, the latter stretching down to the ventral nerve chain and extensions of the hepatopancreas extending between the leg nerves. The hepatopancreas extends to the front of the stomach and to the back to the fourth pleon segment.
Excretion system: The antenna glands of L. hirta are located laterally in the anterior (anterolateral) cephalothorax and are complexly structured. The lobes of the antenna bladder associated with the glands lie in front (anterior) and side (lateral) to the stomach and cover a large part of the hepatopancreas.
Reproductive system: The female sex glands, the ovaries, of L. hirta are paired and located above the hepatopancreas. They are connected below the heart, which gives them an H-shape. In the anterior area, the ovaries encompass the posterior area of the stomach; in the posterior area, the glands extend to the sixth pleonic segment. The male sex glands, the testes or testicles, are also paired, but their extent is limited to the cephalothorax. They are connected on both sides with a draining duct, which, rolled up several times, pull to the genital orifices (gonopores). The latter are located on the coxal segments of the eighth thoracic segment. The rolled up drainage ducts (vasa deferentia) extend into the second pleonic segment on their way.
Nervous system: The foremost part of the central nervous system is the brain. It is relatively small compared to the rest of the body. Nerves move from the brain to the sensory organs (eyes, antennas, antennae). A pair of circumesophageal ("throat enclosing") connective connects the brain of L. hirta with the cephalothoracic ganglion, a compression of several neuromeres in the anterior lower cephalothorax (thorax segments 3–5), which form the ganglia of the segments of the mandible and 1st + 2nd The maxilla, the thoracic segments (I-VIII) and the first pleonal segment correspond. The nerve fiber densities (neuropiles) of the neuromers of the mouthparts are clearly placed together and separated from the individual neuropiles of the treadmill segments (pereiopod segments). The neuromers of the pleon segments 2–6 lie close together in the 7th – 8th. Thoracic segment together and are attached directly to the cephalothoracic ganglion.
Circulatory system: The heart of L. hirta lies in the upper area of the cephalothorax below the carapace and above the anterior section of the intestine. It is held in place by several ligaments and is located in the pericardial sinus, which is bounded laterally and below by the pericardial septum. Three pairs of valve-like openings (ostia) connect the sinus space with the interior of the heart. The inside of the heart is criss-crossed by asymmetrically arranged muscle bundles that represent parts of the heart muscle (myocardium). A total of seven arteries, which can be assigned to five arterial systems (2 pairs, 3 unpaired), run from the heart to the respective organs and body regions. After the blood, the hemolymph, and the arteries have flushed around or through the tissue, it reaches the sinuses of the gills via tissue gaps (lacunae) and canals (sinuses) and, once oxygen has been enriched, is returned to the pericardial sinus via the wide-lumen Branchioperikardialinus .
Muscle systems: The structure or arrangement of the various muscle systems in L. hirta essentially corresponds to that of other decapods. But a specialty concerns the muscles of the pleons. It is largely reduced to a few thin muscle groups. This reduction in muscles is associated with the evolutionary development of the crab habit (carcinization) of L. hirta and the associated turning and flattening of the pleon.
distribution and habitat
Lomis hirta is native to the coast of South Australia. Their distribution area extends from eastern Victoria and Tasmania to around Bunbury in Western Australia . It lives there on mostly stony coasts or on reefs at sea level to depths of a maximum of 30 meters. There it is usually close-fitting below flat stones and boulders. It moves rather slowly and does not flee from attackers, but remains in place, well camouflaged, almost invisible, with all limbs close to the body. Probably fed Lomis hirta as filter feeders of plankton .
Systematics
Jean-Baptiste Lamarck described this type of crayfish in 1818 as Porcellana hirta and thus placed it in the family of porcelain crabs (Porcellanidae). Henri Milne Edwards noted significant differences between Porcellana hirta and the other types of porcelain crabs and believed that they were related to stone and king crabs (Lithodidae). Because he mistakenly described the species and not just the males with missing uropods, which would have been typical for the Lithodidae. He established the genus Lomis with this one species in 1837 . This family assignment was questioned by Eugène Louis Bouvier as early as 1894. He justified his concerns with the symmetry of the physique, which is usually asymmetrical in Lithodidae. Milne Edwards assignment, however, still existed until 1965, before Robert Louis Cecil Pilgrim recognized Milne Edwards errors and corrected the assignment in order to follow Bouvier's work and to place the species in its own family, the Lomisidae. Within the Anomura, Pilgrim suspects a relationship with the land hermit crabs (Coenobitidae) and thus placed them in the superfamily of the Coenobitoidea, which was still described at the time. In 1983 Patsy McLaughlin even raised Lomis hirta into her own superfamily. She found that the species due to its characteristics (number of gills, body symmetry, sexual dimorphism of the uropods, epistome sting, number of antenna base segments and lack of the orbital scale) must have a separate lineage from the other Anomura.
In 2010, Patsy McLaughlin called the question of the phylogenetic allocation of the superfamily within the Anomura as unsolved. According to a molecular genetic and morphological study by Kareen Elisabeth Schnabel and co-authors, Lomis hirta together with the monotypic family of Aeglidae form a common clade ( Australopoda ) with the Chirostyloidea .
The specific epithet hirta comes from Latin and means "shaggy" or "hairy". The name of the genus is derived from the Greek word loma and means "edge" or "hem".
Individual evidence
- ↑ a b c J. Taylor, GCB Poore: Hairy Stone Crab, Lomis hirta. In: Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria. 2011, accessed January 26, 2013 .
- ↑ a b c d K. Davey: Lomis hirta (Family Lomisidae). Australian Government - Department of Sustainability, Environment, Water, Population and Communities, February 7, 2007, accessed January 26, 2013 .
- ↑ a b c d e f g h i Jonas Keiler, Stefan Richter, Christian S. Wirkner: Revealing their innermost secrets: an evolutionary perspective on the disparity of the organ systems in anomuran crabs (Crustacea: Decapoda: Anomura) . In: Contributions to Zoology . tape 85 , no. 4 , p. 361-386 ( contributionstozoology.nl ).
- ↑ a b c P.A. McLaughlin, T. Komai, R. Lemaitre, DL Rahayu: Annotated checklist of anomuran decapod crustaceans of the world (exclusive of the Kiwaoidea and families Chirostylidae and Galatheidae of the Galatheoidea) Part I - Lithodoidea, Lomisoidea and Paguroidea . In: The Raffles Bulletin of Zoology . Supplement No. 23, 2010, p. 5–107 ( PDF, 4.7 MB [accessed January 24, 2013]).
- ↑ Jonas Keiler & Stefan Richter: Morphological diversity of setae on the grooming legs in Anomala (Decapoda: Reptantia) revealed by scanning electron microscopy . In: Zoologischer Anzeiger . tape 250 , 2011, pp. 343-366 , doi : 10.1016 / j.jcz.2011.04.004 .
- ^ PA McLaughlin: A Review of the Phylogenetic Position of the Lomidae (Crustacea: Decapoda: Anomala) . In: Journal of Crustacean Biology . tape 3 , no. 3 , 1983, p. 431-437 , JSTOR : 1548143 .
- ↑ KE Schnabel, ST Ahyong, EW Maas: Galatheoidea are not monophyletic - Molecular and morphological phylogeny of the squat lobsters (Decapoda: Anomura) with recognition of a new superfamily . In: Molecular Phylogenetics and Evolution . tape 58 , 2011, p. 157–168 ( PDF, 1.3 MB [accessed January 24, 2013]).
