''Robia'' is a

monospecific genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

of marine

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 ...

Caulophrynidae, the fanfins. Its only species is ''Robia legula'' which is known from a single

specimen Specimen may refer to: Science and technology * Sample (material), a limited quantity of something which is intended to be similar to and represent a larger amount * Biological specimen or biospecimen, an organic specimen held by a biorepository f ...

collected in the western central

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

where it is found at depths of .

Taxonomy

''Robia'' was first proposed as a genus in 1979 by the American

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...

Theodore Pietsch from a

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''Robia legula'' collected from the Banda Sea in the western Pacific at 4°56.5'S, 129°59.5'E from a depth between . ''Robia'' is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

genus and is one of the two genera along with ''

Caulophryne ''Caulophryne'' is a genus of marine ray-finned fishes belonging to the family Caulophrynidae, the fanfins or hairy anglerfishes. These fishes are found throughout the non-polar oceans of the world. Taxonomy ''Caulophryne'' was first proposed a ...

'', making up the family Caulophrynidae. which the 5th edition of ''

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

'' classifies within the suborder

Ceratioidei Ceratioidei, the deep-sea anglerfishes or pelagic anglerfishes, is a suborder of marine ray-finned fishes, one of five suborders in the order Lophiiformes, the anglerfishes. These fishes are found in tropical and temperate seas throughout the wor ...

of the order Lophiiformes, the anglerfishes.

Etymology

''Robia'' honors Bruce H. Robison of the

Monterey Bay Aquarium Research Institute The Monterey Bay Aquarium Research Institute (MBARI) is a private, non-profit oceanographic research center in Moss Landing, California. MBARI was founded in 1987 by David Packard, and is primarily funded by the David and Lucile Packard Foun ...

, whose nickname was "Robie", and is a

possessive A possessive or ktetic form (Glossing abbreviation, abbreviated or ; from ; ) is a word or grammatical construction indicating a relationship of possession (linguistics), possession in a broad sense. This can include strict ownership, or a numbe ...

recognising his research

bathypelagic fish Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that live on or near the bottom, and reef fish that are associated with coral reefs. ...

. 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 ...

''legula'' means "collector" or "gatherer", Pietsch stated that this was because of the "extraordinary collecting abilities" of this species. Pietsch is assumed to have been referring to the very long

illicium ''Illicium'' is a genus of flowering plants treated as part of the family Schisandraceae,

, the luring apparatus of anglerfishes, of this species which is more than 2.5 times its

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 ...

, as well as to the holotype being collected in an opening-closing net.

Description

''Robia'' is classified within the fanfin family and this family is characterized by have a high degree of

sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

. The females have short, round bodies with large mouths. The lower jaw reaches back past the base of the

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

. The teeth in the jaws are thin, backwards curving and depressible. They have highly elongated

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

and

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 ...

s, with the soft rays of these fins resembling long threads. There are 8 fin rays in the

caudal 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 only ...

. They do not have

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

s. The sensory cells of 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 ...

system are at the tips of the filamentous rays of the dorsal and anal fins. They have a simple esca, or lure, which lacks a bulb but which may have filaments or appendages. The skin is naked and they do not have any dermal spines. The males are much smaller than the females and have more elongated bodies. They have large eyes and large nostrils, with large

olfactory receptor Olfactory receptors (ORs), also known as odorant receptors, are chemoreceptors expressed in the cell membranes of olfactory receptor neurons and are responsible for the detection of odorants (for example, compounds that have an odor) which give ...

s. They have no teeth in the jaws, although there are tooth-like structures on the jaw bones which are used to attach to the larger female. The male do not have elongated dorsal and anal fins but so have large pectoral fins. The juveniles have

s that are lost when they metamorphose into adults, although the relict pelvic bones are retained. However, ''Robia'' is known from a single specimen which was a metamorphosed female. This specimen differed from ''Caulophryne'' in its very elongated illicium, as opposed to The two genera also differ by the count and length of the fin rays in the dorsal and anal fins, in ''Robia'' there are 6 rays in the dorsal fin, the longest is 65% of the standard length, and 5 rays in the anal fin with the longest being 40% of the standard length; while in ''Caulophryne'' there are between 14 and 22 rays in the dorsal fin with the longest ray having its length equivalent to 70% of the

and in the anal fin there are between 12 and 19 fin rays with the longest having its length equivalent to 60% of the standard length. The holoptype of this species had a

of .

Distribution and habitat

''Robia'' is known only from a single specimen collected in the Banda Sea near

Banda Neira Banda Neira (also known as Pulau Neira) is an island in the Banda Islands, Indonesia. It is administered as part of the administrative Banda Islands District (''Kecamatan Kepulauan Banda'') within the Central Maluku Regency in the province o ...

in Indonesia which was collected at a depth between .

Taxonomy

Etymology

Description

Distribution and habitat

References

Further reading