''Hippocampus denise'', also known as Denise's pygmy seahorse or the yellow pygmy seahorse, is a

seahorse A seahorse (also written ''sea-horse'' and ''sea horse'') is any of 46 species of small marine Osteichthyes, bony fish in the genus ''Hippocampus''. The genus name comes from the Ancient Greek (), itself from () meaning "horse" and () meanin ...

of 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 ...

Syngnathidae The Syngnathidae is a family of fish which includes seahorses, pipefishes, and seadragons ('' Phycodurus'' and '' Phyllopteryx''). The name is derived from (), meaning "together", and (), meaning "jaw". The fused jaw is one of the traits that ...

native to the western Pacific.

Description

Denise's pygmy seahorse is a small fish which can reach a maximum length of approximately 2.4 cm, which makes it one of the smallest representatives of the seahorses. This pygmy seahorse has a short snout, slender body with a prehensile tail. Its body is either completely smooth or provided with some polyp-like tubercles, in which case these are fewer and less developed than '' Hippocampus bargibanti''. Its coloration ranges from yellow, more or less bright, to orange with often small dark spots and sometimes darker bands on the tail.

Distribution and habitat

This

pygmy seahorse The pygmy seahorses comprise several species of tiny seahorse in the syngnathid family or Syngnathidae (seahorses and pipefish). Family Syngnathidae is part of order Syngnathiformes, which contains fishes with fused jaws that suck food into tu ...

has been reported from several locations in the western Pacific, including

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (; ), is an island country in Melanesia located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of northern Australia, northeast of New Caledonia, east o ...

Palau Palau, officially the Republic of Palau, is an island country in the Micronesia subregion of Oceania in the western Pacific Ocean. The Republic of Palau consists of approximately 340 islands and is the western part of the Caroline Islands ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

, the Solomon Islands and Micronesia. It can be found at depths between 13 and 100 m, generally hiding in fields of

gorgonians Alcyonacea is the old scientific Order (biology), order name for the informal group known as "soft corals". It is now an unaccepted name for Class (biology), class Octocorallia. It became deprecated . The following text should be considered a hi ...

(e.g., ''

Annella ''Annella'' is a genus of soft corals belonging to the family Subergorgiidae. Species * ''Annella mollis ''Annella mollis (Subergorgia mollis)'' is a species of soft corals belonging to the family Subergorgiidae Subergorgiidae is a fami ...

'', ''

Muricella ''Muricella'' is a genus of corals belonging to the family Acanthogorgiidae. The species of this genus are found in Pacific and Indian Ocean, Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the ...

'' and '' Echinogorgia'').

Biology

Denise's pygmy seahorse uses adaptive camouflage, changing its color to match that of the surrounding gorgonians. It feeds on small

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

and other

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

. An individual will stay on a single coral for the duration of its entire life. The species is

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparity, oviparous and live-bearing viviparity, viviparous reproduction. Ovoviviparous animals possess embryos that develo ...

, and it is the male who broods the eggs in its ventral brood pouch. The latter includes villi rich in capillaries that surround each fertilized egg creating a sort of

placenta The placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas, and waste exchange between ...

supplying the embryos. When fully grown, pups are expelled from the pocket and become autonomous. Males have been recorded as giving birth to 6-7 pups after 11 days of gestation, and carrying out four sequential pregnancies of the same gestation length.

Conservation status

The species is relatively rare and only few data relating to the population as well as its actual distribution exist. Because of this lack of information and the rarity of the species, Denise's pygmy seahorse is currently classified as

Data Deficient A data deficient (DD) species is one which has been categorized by the International Union for Conservation of Nature (IUCN) as offering insufficient information for a proper assessment of conservation status to be made. This does not necessaril ...

by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

. Internationally, it is also listed in Appendix II of the

Convention on International Trade in Endangered Species of Wild Fauna and Flora CITES (shorter acronym for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of inte ...

(CITES) this means that it is on the list of species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilization incompatible with their survival.

Naming

The

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

and 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 ...

honour the diver and underwater photographer Denise Tackett, who died in 2015; she was diving with Sara Lourie, one of the describers of ''H. denise'', when she first encountered this species in the

Lembeh Strait Lembeh Strait is a strait in Indonesia, separating the islands of Sulawesi and Lembeh. The town of Bitung and Tongkoko volcano are located on the western side of the strait. The strait is known for its abundant and colorful marine life, in par ...

in 1999.

References

External links

* {{Taxonbar, from=Q1187728 Seahorses Fish of Palau Taxa named by John Ernest Randall Fish described in 2003 Taxonomy articles created by Polbot