The cactus roach (''Rutilus virgo'') is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of freshwater

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Leuciscidae Leuciscidae is a family of freshwater ray-finned fishes, formerly classified as a subfamily of the Cyprinidae, which contains the true minnows. Members of the Old World (OW) clade of minnows within this subfamily are known as European minnow ...

, which includes the daces, Eurasian minnows and related fishes. This species occurs in central and eastern Europe, including the northern

Balkans The Balkans ( , ), corresponding partially with the Balkan Peninsula, is a geographical area in southeastern Europe with various geographical and historical definitions. The region takes its name from the Balkan Mountains that stretch throug ...

Taxonomy

The cactus roach was first formally described as ''Leuciscus virgo'' in 1852 by the Austrian

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Johann Jakob Heckel Johann Jakob Heckel (23 January 1790 – 1 March 1857) was an Austrian taxidermist, zoology, zoologist, and ichthyology, ichthyologist from Mannheim in the Electoral Palatinate. He worked at the Royal natural history cabinet in Vienna which later ...

with its type locality given as the

Danube River The Danube ( ; see also other names) is the second-longest river in Europe, after the Volga in Russia. It flows through Central and Southeastern Europe, from the Black Forest south into the Black Sea. A large and historically important riv ...

near

Vienna Vienna ( ; ; ) is the capital city, capital, List of largest cities in Austria, most populous city, and one of Federal states of Austria, nine federal states of Austria. It is Austria's primate city, with just over two million inhabitants. ...

in Austria. This species is now classified within the genus ''

Rutilus ''Rutilus'', commonly known as roaches, is a genus of freshwater ray-finned fish belonging to the family Leuciscidae, which includes the daces, Eurasian minnows and related fishes. This genus is a widely distributed lineage of leuciscids and r ...

'' in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Leuciscinae Leuciscinae is a subfamily of freshwater Actinopterygii, ray-finned fishes belonging to the Family (biology), family Leuciscidae, which includes the fishes known as daces, chubs, shiners and minnows. The fishes in this subfamily are mainly found i ...

of the family

. This species and the

pigo The pigoKottelat, M. and J. Freyhof, 2007. Handbook of European freshwater fishes. Publications Kottelat, Cornol, Switzerland. 646 p. (''Rutilus pigus''), or Italian roach, is a species of freshwater ray-finned fish belonging to the family Leucis ...

or Italian roach (''R. pigus''), of the northern Adriatic basin, were previously considered to be the same species. However, molecular analyses published since the late 2000s have shown that these are two separate valid species.

Etymology

The cactus roach belongs to the genus ''Rutilus'', a name which means "red, golden red and reddish yellow" and is an allusion to the red colour of the fins of the

common roach The roach, or rutilus roach (''Rutilus rutilus''), also known as the common roach, is a fresh- and brackish-water fish of the family Cyprinidae, native to most of Europe and western Asia. Fish called roach can be any species of the genera ''Rut ...

''R. rutilus''), the type species of the genus. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''virgo'', means "maid" or "maiden", this is probably derived a German

vernacular name Vernacular is the ordinary, informal, spoken form of language, particularly when perceived as having lower social status or less prestige than standard language, which is more codified, institutionally promoted, literary, or formal. More n ...

for this species, ''fraufisch'' meaning "womanfish", another being ''frauennerfling''.

Description

The cactus roach is told apart from the other roaches in the Danube basin by having a black

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mesotheli ...

and the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

typically has 11 to branched fin rays. The breeding males have two rows of nuptial tubercles on the side of the head above the eyes, these are fused to form ridges, with very large tubercles on the body. There are between 44 and 46 scales along the

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

, the body is laterally compressed, and the snout is blunt and rounded and the mouth is subterminal. The colour of the body is greenish to bluish brown with the

iris Iris most often refers to: *Iris (anatomy), part of the eye * Iris (color), an ambiguous color term *Iris (mythology), a Greek goddess * ''Iris'' (plant), a genus of flowering plants * Iris (given name), a feminine given name, and a list of peopl ...

being silvery. This species has a maximum

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

of .

Distribution and habitat

The cactus roach is found in central and eastern Europe where it is indigenous to the drainage system of the Danube from

Baden-Württemberg Baden-Württemberg ( ; ), commonly shortened to BW or BaWü, is a states of Germany, German state () in Southwest Germany, east of the Rhine, which forms the southern part of Germany's western border with France. With more than 11.07 million i ...

in southern Germany to the

Iron Gates The Iron Gates (; ; ; Hungarian: ''Vaskapu-szoros'') is a gorge on the river Danube. It forms part of the boundary between Serbia (to the south) and Romania (north). In the broad sense it encompasses a route of ; in the narrow sense it only ...

on the frontier between Serbia and Romania. The true extent of its distribution is unclear because the sheer size of the Danube and its tributaries make comprehensive surveys very difficult. It appears to be restricted to the lower reaches of rivers draining northern slopes of the Alps in southern Germany and Austria, and its known distribution in the

Tisza The Tisza, Tysa or Tisa (see below) is one of the major rivers of Central and Eastern Europe. It was once called "the most Hungarian river" because it used to flow entirely within the Kingdom of Hungary. Today, it crosses several national bo ...

River system is made up of a comparatively small area where the borders of Hungary, Slovakia and Ukraine meet. Since 2010 the cactus roach has been recorded from a number of new sites in Ukraine, although these all are within around of the previous known edge of its distribution. On the other hand, historical records from the Morava River suggest that it used to occur upstream as far as the Thaya River in Austria and beyond

Olomouc Olomouc (; ) is a city in the Czech Republic. It has about 103,000 inhabitants, making it the Statutory city (Czech Republic), sixth largest city in the country. It is the administrative centre of the Olomouc Region. Located on the Morava (rive ...

in the Czech Republic, several hundred kilometres of linear river length. However, recent records appear to show that this species is probably only found to the lowermost stretch of the river. The cactus roach is mainly found in deep stretches of rivers with a current.

Biology

The cactus roach feeds on benthic invertebrates all year and adds

periphyton Periphyton is a complex mixture of algae, cyanobacteria, heterotrophic microbes, and detritus that is attached to submerged surfaces in most aquatic ecosystems. The related term Aufwuchs ( German "surface growth" or "overgrowth", ) refers to the ...

and plant matter to its diet in summer. In the

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

season the adults migrate upstream to spawn at specific sites in reaches with aquatic vegetation and well washed gravel in riffles in water less than in depth.

References

{{Taxonbar, from=Q2626614 Rutilus Fish described in 1852 Taxa named by Johann Jakob Heckel Freshwater fish of Europe