Munida rugosa
Encyclopedia
Munida rugosa, commonly known as the rugose squat lobster or plated lobster, is a species
of decapod
crustacean
found in the north east Atlantic Ocean
and the Mediterranean Sea
.
for some time but in 1986, Rice and de Saint Laurent examined the literature and specimens in collections
and determined that there were four species involved. They determined that the correct names were Munida rugosa (Fabricius, 1775), M. tenuimana G. O. Sars, 1872, M. intermedia A. Milne Edwards & Bouvier, 1899, and M. sarsi Huus, 1935. The first three species occur in both the Atlantic Ocean and the Mediterranean Sea while M. sarsi is found only in the Atlantic. The name M. bamffia was used extensively in the 19th century and early 20th century but it seems to have been used for two species, M. intermedia and M. rugosa. The specific epithet "bamffius" was itself an error as Thomas Pennant
was naming his newly described species after the town of Banff
in Scotland near where his specimen was found.
and abdomen. It is up to 10 centimetres (3.9 in) long but like other members of the genus
, it folds its abdomen beneath its cephalothorax
. The carapace including the rostrum
is about 30 millimetres (1.2 in) long. The carapace has a few spines on the back edge and the rostrum has a single central spine
, flanked by two shorter spines above the eyes. The thread-like antennae
are slightly shorter than the first pair of appendages which are tipped by long narrow white pincers. The next three pairs of limbs also have white tips and are used for walking. The fifth pair is particularly thin and is usually held underneath the margins of the carapace. The eyes are relatively small in this species and the morphology varies over its range. More southerly specimens are more spiny, have more seta
e on the abdomen and have longer, more slender limbs
.
, around Madeira
, in the north eastern Atlantic Ocean
, in the North Sea
and adjacent continental waters north of 25°N
. at depths of up to 150 metres (492.1 ft), typically in cracks or under boulders.
is followed by spawning
, larva
l release and larval settling. The eggs are carried in the female's brood patch and the larvae
are released at the most favourable season for their survival when there is the most particulate food available. In a study of M. rugosa from the west of Scotland, it was found that 86% of the females carrying embryos had mated with more than one male.
It has been found that some larger males exhibit sexual dimorphism
in that their claws become arched rather than being straight. This seems to be a form of sexual selection and it may be that such chela are more able to inflict puncture wounds when males are interacting in competition for females.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of decapod
Decapoda
The decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
found in the north east Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
.
Taxonomy
There has been confusion over the nomenclature of certain members of the genus MunidaMunida
Munida is the largest genus of squat lobsters, with over 240 species.-Species:*Munida abelloi Macpherson, 1994 *Munida acacia Ahyong, 2007 *Munida acantha Macpherson, 1994 *Munida aequalis Ahyong & Poore, 2004 *Munida affinis A...
for some time but in 1986, Rice and de Saint Laurent examined the literature and specimens in collections
Zoological specimen
A zoological specimen is an animal or part of an animal preserved for scientific use.Various uses are : to verify the identity of a , to allow study, increase public knowledge of zoology.Zoological specimens are extremely diverse...
and determined that there were four species involved. They determined that the correct names were Munida rugosa (Fabricius, 1775), M. tenuimana G. O. Sars, 1872, M. intermedia A. Milne Edwards & Bouvier, 1899, and M. sarsi Huus, 1935. The first three species occur in both the Atlantic Ocean and the Mediterranean Sea while M. sarsi is found only in the Atlantic. The name M. bamffia was used extensively in the 19th century and early 20th century but it seems to have been used for two species, M. intermedia and M. rugosa. The specific epithet "bamffius" was itself an error as Thomas Pennant
Thomas Pennant
Thomas Pennant was a Welsh naturalist and antiquary.The Pennants were a Welsh gentry family from the parish of Whitford, Flintshire, who had built up a modest estate at Bychton by the seventeenth century...
was naming his newly described species after the town of Banff
Banff, Aberdeenshire
Banff is a town in the Banff and Buchan area of Aberdeenshire, Scotland. Banff is situated on Banff Bay and faces the town of Macduff across the estuary of the River Deveron...
in Scotland near where his specimen was found.
Description
M. rugosa is orange with transverse bands of darker colour on the carapaceCarapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
and abdomen. It is up to 10 centimetres (3.9 in) long but like other members of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, it folds its abdomen beneath its cephalothorax
Cephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
. The carapace including the rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....
is about 30 millimetres (1.2 in) long. The carapace has a few spines on the back edge and the rostrum has a single central spine
Spine (zoology)
A spine is a hard, thorny or needle-like structure which occurs on various animals. Animals such as porcupines and sea urchins grow spines as a self-defense mechanism. Spines are often formed of keratin...
, flanked by two shorter spines above the eyes. The thread-like antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
are slightly shorter than the first pair of appendages which are tipped by long narrow white pincers. The next three pairs of limbs also have white tips and are used for walking. The fifth pair is particularly thin and is usually held underneath the margins of the carapace. The eyes are relatively small in this species and the morphology varies over its range. More southerly specimens are more spiny, have more seta
Seta
Seta is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.-Animal setae:In zoology, most "setae" occur in invertebrates....
e on the abdomen and have longer, more slender limbs
Decapod anatomy
The decapod crustacean, such as a crab, lobster, shrimp or prawn, is made up of nineteen body segments grouped into two main body parts, the cephalothorax and the abdomen. Each segment may possess one pair of appendages, although in various groups these may be reduced or missing...
.
Distribution
M. rugosa is found in the western Mediterranean SeaMediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
, around Madeira
Madeira
Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...
, in the north eastern Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, in the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
and adjacent continental waters north of 25°N
25th parallel north
The 25th parallel north is a circle of latitude that is 25 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Indian Ocean, the Pacific Ocean, North America and the Atlantic Ocean....
. at depths of up to 150 metres (492.1 ft), typically in cracks or under boulders.
Biology
GametogenesisGametogenesis
Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes. Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic division of diploid gametocytes into various gametes,...
is followed by spawning
Spawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
, larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l release and larval settling. The eggs are carried in the female's brood patch and the larvae
Crustacean larvae
Crustaceans may pass through a number of larval and immature stages between hatching from their eggs and reaching their adult form. Each of the stages is separated by a moult, in which the hard exoskeleton is shed to allow the animal to grow...
are released at the most favourable season for their survival when there is the most particulate food available. In a study of M. rugosa from the west of Scotland, it was found that 86% of the females carrying embryos had mated with more than one male.
It has been found that some larger males exhibit sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
in that their claws become arched rather than being straight. This seems to be a form of sexual selection and it may be that such chela are more able to inflict puncture wounds when males are interacting in competition for females.