''Salmacis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

sea urchin Sea urchins or urchins () are echinoderms in the class (biology), class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body cove ...

s in the family

Temnopleuridae ''Temnopleuridae'' is a family (biology), family of sea urchins in the infraorder Temnopleuridea. Genera * ''Amblypneustes'' Louis Agassiz, L. Agassiz, 1841 * ''Erbechinus'' Jeannet, 1935 * ''Holopneustes'' Louis Agassiz, L. Agassiz, 1841 * ''Me ...

. Members of ''Salmacis'' are found primarily in tropical and subtropical marine waters across the Indo-Pacific region, including coastal areas of Indonesia, Malaysia, Philippines, Singapore, Thailand, Vietnam, Sri Lanka, India, Australia, and parts of East Africa. Some habitats include shallow waters of

seagrass meadow A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and ...

s, sandy substrates, and

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s. They can be found at depths ranging from intertidal zones to 90 meters below sea level.

Description

The original description of ''Salmacis'' was recorded by

Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he recei ...

in 1841, with the type species '' Salmacis bicolor''. ''Salmacis'' urchins have hemispherical shells (

tests Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film) ...

) that are globular or subconical in shape. Their bodies are covered with short, thick, but sharp spines (

radiole A radiole is a heavily ciliated feather-like tentacle found in highly organized clusters on the crowns of Canalipalpata. Canalipalpata is an order of sessile marine polychaete worms consisting of 31 families (including the Sabellidae, Serpulida ...

), and

pedicellaria A pedicellaria (: pedicellariae) is a small wrench- or claw-shaped appendage with movable jaws, called valves, commonly found on echinoderms (phylum Echinodermata), particularly in sea stars (class Asteroidea) and sea urchins (class Echinoidea). ...

e to deter predators. Their bodies exhibit pentaradial symmetry, with fivefold organization radiating from a central axis that connects the mouth (

peristome Peristome (from the Greek language, Greek ''peri'', meaning 'around' or 'about', and ''stoma'', 'mouth') is an anatomical feature that surrounds an opening to an organ or structure. Some plants, fungi, and shelled gastropods have peristomes. In mo ...

) on the lower, oral surface to the anus (

periproct The periproct is the final body segment in annelid worms. The anus is located on this segment. The term also refers to the small region surrounding the anus of the sea urchin. See also *Prostomium *Earthworm *Sea urchin Sea urchins or urchins ...

) positioned at the upper aboral apex.

Ambulacral Ambulacral is a term typically used in the context of anatomical parts of the phylum Echinodermata or class Asteroidea and Edrioasteroidea. Echinoderms can have ambulacral parts that include ossicles, plates, spines, and suckers. For example, sea ...

pores are arranged in pairs, with crenulated

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projectio ...

s forming several vertical rows which appear as horizontal series on each interambulacral plate. Small pits or angular pores are located at the junctions of the coronal plates. The

masticatory Chewing or mastication is the process by which food is crushed and ground by the teeth. It is the first step in the process of digestion, allowing a greater surface area for digestive enzymes to break down the foods. During the mastication proc ...

apparatus is similar to other genera like '' Diadema'' and '' Echinothuriids'', except for the compass depressor, which ends in a spatula-shaped tip.

Diet

Like other sea urchins in the class

Echinoidea Sea urchins or urchins () are echinoderms in the class Echinoidea. About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of . They typically have a globular body covered by a spiny ...

, ''Salmacis'' urchins are omnivorous scavengers and

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

feeders. Their diets consists of

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

and soft-bodied organisms like

sea pen Sea pens are marine cnidarians belonging to the superfamily Pennatuloidea, which are colony-forming benthic filter feeders within the order Scleralcyonacea. There are 14 families within the order and 35 extant genera, and it is estimated a ...

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic animal, aquatic invertebrate animals, nearly all living in sedentary Colony (biology), colonies. Typically about long, they have a spe ...

ns, and

jellyfish Jellyfish, also known as sea jellies or simply jellies, are the #Life cycle, medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animal ...

Reproduction

''Salmacis'' urchins are

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

with separate male and female sexes. They reproduce through

external fertilization External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then ...

. Their eggs are retained either on the mouth (

), near the anus (

), or nestled deep within the depressions of the petaloid regions. Their

gonad A gonad, sex gland, or reproductive gland is a Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gon ...

s serve both reproduction and nutrient storage functions.

Morphology

Members of the genus can be differentiated based on their coloration. For example, '' Salmacis bicolor'' is distinctive by its two-toned coloration. On the other hand, species like '' Salmacis sphaeroides'' are predominantly white or olive-green, while its spines are green with reddish-brown, purple, white, or green brands.

Species

These are species according to the

Global Biodiversity Information Facility The Global Biodiversity Information Facility (GBIF) is an international organisation that focuses on making scientific data on biodiversity available via the Internet using web services. The data are provided by many institutions from around th ...

and

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

. Species like ''Salmacis sphaeroides'' and ''Salmacis bicolor'' are distributed across the Indo-Pacific Ocean, scattered across coastal areas in Southern China, Southern Japan, Vietnam, Malaysia, and Singapore. ''Salmacis virgulata'' was found and recorded in Sri Lanka. ''Salmacis belli'' can be found along the coasts of Northern Australia. * '' Salmacis belli'' Döderlein, 1902 * '' Salmacis bicolor'' L. Agassiz in L. Agassiz & Desor, 1846 * '' Salmacis nuda'' Currie, 1930 * '' Salmacis roseoviridis'' Koehler, 1927 * '' Salmacis rubricincta'' H.L. Clark, 1925 * '' Salmacis sphaeroides'' (Linnaeus, 1758) * '' Salmacis virgulata'' L. Agassiz in L. Agassiz & Desor, 1846

References

External links

Original description of ''Salmacis''
from Biodiversity Heritage Library (BHL), Agassiz, L. & Desor, P. J. E. 1846. Catalogue raisonné des familles, des genres, et des espèces de la classe des échinodermes. Annales des Sciences Naturelles, Troisième Série, Zoologie 6, 305-374. p. 359.
Information on ''Salmacis'' L. Agassiz, 1841
from the World Register of Marine Species (WoRMS)
Genus ''Salmacis''
on iNaturalist * More external links on GBIF see
''Salmacis'' L.Agassiz, 1841
{{Authority control Temnopleuridae Echinoidea genera