The visitor (''Adventor elongatus''), also known as the sandpaper velvetfish,is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

, a

velvetfish Little velvetfishes or simply velvetfishes are a Family (biology), family, the Aploactinidae, of marine ray-finned fishes classified within the order Scorpaeniformes. They are small fish that have skin with a velvet texture. They live on the sea ...

belonging to the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Aploactinidae Little velvetfishes or simply velvetfishes are a family, the Aploactinidae, of marine ray-finned fishes classified within the order Scorpaeniformes. They are small fish that have skin with a velvet texture. They live on the sea bottom close to t ...

. It is the only member of the

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 "unispec ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Adventor''. This species is found the

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

waters along the coasts of

Papua New Guinea Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ...

and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Taxonomy

The visitor was first formally described as ''Membracidichthys elongatus'' by the Australian

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, 33,400 species of fish had been described as of Octobe ...

Gilbert Percy Whitley Gilbert Percy Whitley (9 June 1903 – 18 July 1975) was a British-born Australian ichthyologist and malacologist who was Curator of Fishes at the Australian Museum in Sydney for about 40 years. He was born at Swaythling, Southampton, England, an ...

with the type locality given as the Tiflis Passage in

Moreton Bay Moreton Bay is a bay located on the eastern coast of Australia from central Brisbane, Queensland. It is one of Queensland's most important coastal resources. The waters of Moreton Bay are a popular destination for recreational anglers and are ...

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

. Whitley classified his new species in a new subgenus of ''Membracidichthys'' which was subsequently recognised as a valid monotypic genus ''Adventor''. This taxon is classified within the family Aploactinidae in the

suborder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

Scorpaenoidei Scorpaenoidei is a suborder of ray-finned fishes, part of the order Scorpaeniformes, that includes the scorpionfishes, lionfishes and velvetfishes. This suborder is at its most diverse in the Pacific and Indian Oceans but is also found in the A ...

within the order

Scorpaeniformes The Scorpaeniformes are a diverse order of ray-finned fish, including the lionfishes and sculpins, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of species, with over 1,320. They are ...

, although thios family is also treated as a subfamily of the

stonefish ''Synanceia'' is a genus of ray-finned fish belonging to the subfamily Synanceiinae, the stonefishes, which is classified within the family Scorpaenidae, the scorpionfishes and relatives. Stonefishes are venomous, dangerous, and fatal to huma ...

family

Synanceiidae Synanceiinae is a subfamily of venomous ray-finned fishes, waspfishes, which is classified as part of the family Scorpaenidae, the scorpionfishes and their relatives. These fishes are found in the Indo-Pacific oceans. They are primarily marin ...

within the Scorpaenoidei, which in turn is treated as a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

within the order Perciformes. The genus name ''Adventor'' is Latin for "visitor", Whitley did not explain the allusion but as this was the only species of its genus, ''Membracidichthys'', which is distributed in Indonesia and the Philippines which visited Australian waters. The specific name, ''elongatus'', means "elongated" as it had the most elongated body in the genus ''Membracidichthys''.

Description

The visitor has a head with a low dorsal profile and a projecting chin and a mouth which does not reach to underneath the small eye. There are villiform teeth on the jaws and the vomer. There is a barbel which hangs over the corner of the upper lip and there are pits and barbel like growths on the chin. There are three blunt spines on the preorbital, pointing in diverging directions, and 2 suborbital spines. The

preoperculum This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes. A B C ...

has 5 blunt spines on its margin and there is a single weak spine on the operculum. This species has a compressed, long body which is bare of scales but which is densely covered in velvety warts extending to around the eyes. The

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

has its origin clearly to the rear of the eye, the first three dorsal spines, the second of which is the longest, are separated from the rest of the dorsal spines. The ultimate dorsal spine is connected to the higher soft rayed part of the fin which in turn is connected to the caudal peduncle. The dorsal fin has 13 spines and 10 soft rays while the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

has 11 soft rays. All the fin rays are simple. The caudal fine is rounded. The overall colour is dark-reddish chocolate-brown, marked with irregular variably coloured paler and darker regions, especially on the fins. There are small dark-brown eyespots on the top of the head, nape, and around the spiny part of the dorsal fin with vague brown spots along the inner rear edge of the gill slit. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

had a

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of .

Distribution and habitat

The visitor has been recorded from

Exmouth Gulf Exmouth Gulf is a gulf in the north-west of Western Australia. It lies between North West Cape and the main coastline of Western Australia. It is considered to be part of the Pilbara Coast and Northwest Shelf, and the Carnarvon Basin geologi ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

to Moreton Bay in Queensland, it has also been recorded in New Guinea. This

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They occ ...

is found in inshore waters.

References

{{Taxonbar, from= Q2336843 , from2=Q1532565 Aploactinidae Fish described in 1952 Taxa named by Gilbert Percy Whitley