Oreoglanis is a 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...

 of catfish

Catfish

Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...

es (order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Siluriformes) of the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Sisoridae

Sisoridae

Sisoridae is a family of catfishes . These Asian catfish live in fast-moving waters and often have adaptations that allow them to adhere to objects in their habitat.-Taxonomy:...

.

Taxonomy

The taxonomy

Taxonomy

Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 of this group is currently under discussion and changes seem inevitable as the group is suspected to be non-monophyletic.

Based on morphology, Oreoglanis has been divided into two species groups. According to the original description of these groups, the O. siamensis species group is distinguished by having an emarginate caudal fin, and a lower lip notched medially with an entire or weakly laciniate posterior margin, while the O. delacouri species group is distinguished by having a lunate caudal fin (sometimes with strap-like extensions of the simple principal caudal rays), and a lower lip without a median notch with prominent extensions along the posterior margin. It has been suggested that only the marginal morphology of lower lip can be employed to recognize the two species groups. The O. siamensis group includes O. insignis, O. macropterus, O. setiger and O. siamensis, as well as the newer species O. immaculatus and O. jingdongensis based on the Chinese distribution of all members of this group. The O. delacouri group consists of O. delacouri, O. frenatus, O. infulatus, O. lepturus, O. macronemus and O. hypsiurus.

Distribution

These fish live in fast-flowing streams in China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, mainland Southeast Asia

Southeast Asia

Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

 and the Indian subcontinent

Indian subcontinent

The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...

. They are mainly distributed in the Mekong, upper Salween

Salween River

The Salween is a river, about long, that flows from the Tibetan Plateau into the Andaman Sea in Southeast Asia. It drains a narrow and mountainous watershed of that extends into the countries China, Burma and Thailand. Steep canyon walls line the swift, powerful and undammed Salween, one of the...

, and Irrawaddy River

Ayeyarwady River

The Irrawaddy River or Ayeyarwady River is a river that flows from north to south through Burma . It is the country's largest river and most important commercial waterway. Originating from the confluence of the N'mai and Mali rivers, it flows relatively straight North-South before emptying through...

 drainages. They range from the Irrawaddy drainage of Burma east to the Lam River drainage in central Vietnam

Vietnam

Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...

.

Description

They are easily distinguished from other catfishes by their strongly depressed head and body, and greatly enlarged paired fins that have been modified to form an adhesive apparatus. The flattened shape of these fish and the large pectoral and pelvic fins provide essential adhesion in the fast-flowing waters they live in.

Members of this genus are distinguished by the combined presence of a continuous groove behind the lip (post-labial groove), the gill

Gill

A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...

 openings not extending onto the underside (venter), homodont dentition in upper jaw pointed, in two patches, joined into a continuous band, heterodont

Heterodont

The anatomical term heterodont refers to animals which possess more than a single tooth morphology. For example, members of the Synapsida generally possess incisors, canines , premolars, and molars. The presence of heterodont dentition is evidence of some degree of feeding/hunting specialization...

 dentition in the lower jaw characterized by an inner row of pointed teeth and outer row of short, spatulate (shovel-like) teeth, and 16–18 branched pectoral rays. The head and body are moderately broad and strongly depressed. The skin is smooth dorsally. The eyes are minute, dorsolateral, and under the skin (subcutaneous). The lips are thin and papilla

Papilla (fish mouth structure)

The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...

ted. Teeth in upper jaw are pointed and in large broad band with a small median indentation and rounded sides.