Italian crab

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Italian crab
Italian crab (Eriphia verrucosa), male

Italian crab ( Eriphia verrucosa ), male

Systematics
Sub-stem : Crustacea
Class : Malacostraca
Order : Decapoda
Family : Eriphiidae
Genre : Eriphia
Type : Italian crab
Scientific name
Eriphia verrucosa
( Forsskål , 1775)

The Italian crab ( Eriphia verrucosa ) is a crab of the genus Eriphia from the Eriphiidae family that lives near the coast and is found in the Black Sea, the Mediterranean Sea and the east Atlantic coast. The species Eriphia verrucosa was first described by Peter Forsskål in 1775 in the Izmir region of the Aegean Sea . It is a benthic species whose habitat is limited to coastal areas with a water depth of up to 15 m. Popular in the Mediterranean as a table crab, the Italian edible crab has a major impact on the local ecosystem as prey and predator.

morphology

Italian pocket cancer can be recognized by the following characteristics: It is a heavily armored, dorsoventrally flattened cancer. Its cephalothorax consists of eight segments and is wider than it is long, it is, as with all crabs, covered by a carapace , this has no rostrum (a pointed process forward, between the eyes). Spines are located on the front edge of the carapace and between the eyes. The spines are slightly arched, not very pointed and relatively short.

As is typical for crabs, the abdomen is folded forward and carried under the cephalothorax. Of the five pairs of peraeopods , the first is transformed into asymmetrical chelipeds . The remaining pairs of peraeopods are walking legs. The pleopods are largely regressed in males and are only used in females to carry the eggs.

Scissors

The scissors (or chelae) are asymmetrical, with the larger rounded cusps and the smaller one with many pointed smaller cusps arranged in rows. In terms of color, the powerful scissors are clearly distinguishable from the rest of the body by a reddish-brown to black color. There are six somites in the abdominal area. In areas where the prey of the Italian crab consists largely of shell-armored molluscs , the claws of individuals tend to be larger than those of other diets.

coloring

The color of the carapace is between green-brown and red-brown, depending on the individual, with random patterns of yellow spots spread over the body. The pattern and color are dependent on environmental factors, growth and sexual maturity and can change during the life cycle. The reason for the coloring is the camouflage for visual protection against predators, which with green, red and brown tones offers an optimal adaptation to the rocky subsoil overgrown with plants. The yellow spots, which are distributed on the body, are used for self-representation, recognition of other individuals and communication. The color is either in the exoskeleton itself or in the epidermis below and is formed by the protein complex crustacyanin (CRCN) by converting the carotenoid astaxanthin. All of the coloring results from pigments on the exoskeleton, as well as the variation of chromatophores in the epidermis. The constellation and number of chromatophores form a unique pattern for each individual and are the reason for the common English names of the Italian crab "warty crab" or "yellow crab".

Sex discrimination

The distinction between the sexes is made by checking the folded abdomen. In males, the valves are rather small and triangular, while the females have large oval valves. The two front pairs of pleopods are converted to gonopods in males . In addition, females can be recognized by eggs carried under the pleon during the breeding season from May to June .

Females and males of the same age differ in body size with the ratio between weight and carapace length, in the form weight = 15.02 × carapace length 0.3228 for males and weight = 8.86 × carapace length 0.4073 . A maximum carapace width of up to 10 cm and a maximum carapace length of 6.1 cm in males and up to 7 cm in width and 5.5 cm in length in females were found in various study areas.

Taxonomy

The Italian crab was assigned to the Xanthidae family by Rupert Riedl in 1983 . The Eriphiidae are often mentioned as a subfamily of the Xanthidae. Although there are similarities, the current state of the systematic classifications is a separation into two different families, in which E. verrucosa is assigned to the family of the Eriphiidae.

Habitat

The Italian crab lives benthically in crevices, whereby the selection does not differentiate between natural rock formations and man-made ones such as walls or buildings in the surf zone. The decisive factor is the size of the opening in the rock. The construction can be divided into two categories depending on the depth at which it is located. The crevices in the rock, which lie just below the tide line in a water depth of up to 2 m and are overgrown by many plants, are often inhabited by younger and smaller crabs. Rock crevices at the outer borders of stone coasts, with a water depth of 2-15 m, are inhabited by larger individuals. In these, the removal of sediment and the pruning of plants in the entrance area of ​​the crevice can clearly be observed. A distinguishing feature of the crevices inhabited by crabs is that shell fragments of the animals that have become prey collect in front of the crevice. The accumulation of shells of former prey in front of the burrow becomes more likely with deeper water, as currents and waves ensure dispersion in the shallow water. The distance between the inhabited rock crevices increases with the size of the inhabitants and is between 6 and 20 meters. These distances are the effect of the radius of activity of E. verrucosa around its own burrow. The territorial behavior, which manifests itself in violent fights with a high risk of injury for the participants, ensures the irregular distances between the inhabited crevices.

nutrition

The Italian crab predatory feeds on mussels, gastropods, hermit crabs, molluscs and polychaetes. The size of the scissors has a direct impact on nutrition, as the larger the size of the scissors, the greater the chance of larger prey animals with harder shells, such as mussels, other crabs and shell-armored mollusks. Depending on environmental factors, the morphology of the shears and with it, the type of prey varies. The Italian crab is usually active at dusk and at night to avoid diurnal predators. The day is spent in the burrow and only left to search for food at dawn. The foraging usually only takes place near the burrow. As E. verrucosa moves further from the burrow, the prey is carried near the burrow before it is consumed. The bigger the prey, the more likely it is that the crab will first seek the vicinity of the burrow. This behavior is also the reason for the accumulation of shell residues from the prey near the burrow.

Reproduction and development

Reproduction takes place externally and separately. The Italian crab is one of the heterotremata, a group of crabs in which the sexual orifices of the females are located on the sternum and in the males on the first pair of pleopods that have been converted into gonopods. In the spring the individuals migrate into shallow waters. The mating season lasts from May to June and depends on environmental factors such as hours of sunshine, water temperature, diet and the salinity of the water. When mating, the female is placed on her back by the male using his claws. Spermatophores are then attached to the sternal genital opening with the help of the gonopods and an adhesive substance. The spermatophores are stored directly in the female genital tract. Compared to the spermatophores of other crab species, in which fertilization does not take place directly, they are relatively small and rather rounded. The shape can be explained by the possible blockage of the female's genital tract, since the blockage prevents successful mating with other males.

In addition, they belong to the group of pleocyemata, which means that the females carry the eggs around with them attached to their pleons. The pleon of the sexually mature females is wider than that of the younger ones or that of the males to protect the fertilized eggs. The development of the eggs can be divided into different stages based on their appearance. Stage one are recently produced eggs, which can be recognized by a light yellow color. Embryonic pigmentation is not yet evident. The second stage begins with the recognizable pigmentation of the embryo and a discoloration of the egg mass to brownish. In the third stage of the eggs one can see the clearly developed embryo. As the eggs age, the color becomes increasingly dark. The protection of the female ends when the larvae hatch. Males show no brood protection behavior, however, for a short period after mating, protection of the female was observed, which can, however, also be ascribed to repelling rivals. After hatching, the larva goes through four stages of metamorphosis from zoelope to megalope until it finally becomes a juvenile animal. Before the animal has reached adult age, it will go through several moults.

distribution

Italian edible crab is widespread. It can be found in the Black Sea, the Mediterranean Sea, and the east Atlantic coast from Brittany to Mauritania and the Azores. Although the coastal habitat is inhabited up to a water depth of 15 m, there is a greater abundance of coasts protected from direct waves.

Use and consumption

The Italian crab has a comparatively high commercial value in the Mediterranean area due to its high protein content as well as the amount of essential amino acids and unsaturated fatty acids and can often be found in the local fish markets depending on the season. In the Black Sea it is the largest crab with a carapace width of up to 10 cm, but is less used as a table crab. According to several recent studies, the crab meat has an average protein content of 20%. The protein content is thus higher than that of other edible crabs that are eaten in the Mediterranean region. In addition, an average of 2.35% ash was found in the muscle tissue.

ecology

In the Black Sea, the Italian crab is used as an indicator of heavy metal pollution. Metal enrichment has been demonstrated in coastal cities and traced back to the level of industrialization in the region. Since a simple connection between heavy metals in the environment and in the organism can be demonstrated, E. verrucosa is suitable as a bio-indicator for heavy metal pollution. According to analyzes from 2015, however, no metal content in the edible meat of E. verrucosa that is dangerous for humans was found.

Web links

Commons : Eriphia verrucosa  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e f g Ulas A. & Aydin C. (2011): Length-Weight Relationships of Eriphia verrucosa Forskal (1775) from the Aegean Sea (Linnaeus, 1758) . In Journal of Animal and Veterinary Advances 10 (8) , pp. 1061-1602
  2. ↑ a b c d e Silva et al. (2010): Cheliped morphological variation of the intertidal crab Eriphia verrucosa across shores of differing exposure to wave action . In Journal of Experimental Marine Biology and Ecology 391 , pp. 84-91
  3. ↑ a b Jouili S., Arculeo M., Mansour L. & Rabaoui L. (2016): Biological characteristics of three Brachyuran crab species in the Lagoon of Elbibane, South-Eastern Tunisia . In Cahiers de Biologie Marine .
  4. ↑ a b Wolf EM (2016): Habitat Litoral: A comparison of brachyuric crustacea in the rock littoral around the island of Krk, Croatia , Bachelor thesis, Innsbruck
  5. ↑ a b c d e Castro P. et al., Edited by FR Schram & JC von Vaupel Klein: Treatise on zoology - Anatomy, Taxonomy, Biology - The Crustacea, complementary to the volumes of the Traitè de Zoologie . Volume 9. Published by Brill, Leiden & Boston 2010
  6. ↑ Pessani D., T. & Tirelli flagella S. (2004): Key for the identification of Mediterranean brachyuran megalopae . In Mediterranean Marine Science Vol. 5/2, pp. 53-64.
  7. ↑ a b c Karadurmus U., Aydin M. (2016): An investigation on some biological and reproduction characteristics of Eriphia verrucosa (Forskål, 1775) in the South Black Sea (Turkey) . In Turkish Journal of Zoology 40 , pp. 461-470.
  8. ^ Rupert Riedl: Fauna and Flora of the Mediterranean Sea - a systematic marine guide for biologists and nature lovers , Paul Parey Verlag, Hamburg and Berlin 1983
  9. ↑ Ng PKL, Guinot D. & Davie PJ (2008): Systema Brachyurorum Part I: An annotated checklist of extant brachyuran crabs of the world. In The Raffles Bulletin of Zoology , 17/2008, pp. 1-286.
  10. ^ A b c Rossi AC & Parisi V. (1973): Experimental Studies of Predation by the CRAB Eriphia verrucosa on Both Snail and Hermit CRAB Occupants of Conspecific Gastropod Shells . In Bolletino di zoologia , 40: 2, 117-135, doi : 10.1080 / 11250007309430063
  11. ↑ a b Erkan M., Tunali Y., Balkis H. & Oliveria E. (2009): Morphology of testis and vas deferens in the xanthoid crab, Eriphia verrucosa (Forskal, 1775) (Decapoda: Brachyura) . In Journal of Crustacean Biology 29 (4), pp. 458-465.
  12. ^ Krol, RM, Hawkins WE & RM Overstreet (1992): Reproductive Components . In FW Harrison & AG Humes Microscopic Anatomy of Invertebrates, Vol. 10. Decapoda Crustacea . Pp. 295-343. Published by Wiley-Liss, Inc. New York.
  13. ↑ Ozogul Y. et al. (2013): The Effects of Season and Gender on the proximate and fatty acid Profile of male and female warty crab (Eriphia verrucosa) from black sea
  14. ↑ a b Kaya Y., Turan H. & Erdem EM (2009): Determination of Nutritional Quality of Warty Crab (Eriphia verrucosa Forsskal, 1775) . In Journal of Animal and Veterinary Advances 8 (1) , pp. 120-124.
  15. ↑ Zotti M. et al. (2016): Comparative analysis of the proximate and elemental composition of the blue crab Callinectes sapidus, the warty crab Eriphia verrucosa, and the edible crab Cancer pagurus .
  16. ↑ Bat L. & Öztekin HC (2015): Heavy Metals in Mytilus galloprovincialis, Rapana venosa and Eriphia verrucosa from the Black Sea Coasts of Turkey as Bioindicators of Pollution . In: Walailak Journal Sci & Tech 2016 ; 13 (9), pp. 715-728.