''Sesarmops'' is a genus of

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

s in the family

Sesarmidae The Sesarmidae are a family of crabs, previously included in the Grapsidae by many authors. Several species, namely in '' Geosesarma'', '' Metopaulias'', and '' Sesarma'', are true terrestrial crabs. They do not need to return to the sea even fo ...

. Its members are distributed through the

Indo-West-Pacific The Indo-Pacific is a vast biogeography, biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Oc ...

oceanic region. They live in

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

forest streams near the coast, and in

mangrove A mangrove is a shrub or tree that grows mainly in coastal saline water, saline or brackish water. Mangroves grow in an equatorial climate, typically along coastlines and tidal rivers. They have particular adaptations to take in extra oxygen a ...

Taxonomy

''Sesarmops'' was defined in 1970 when Serène and Soh re-organised the existing

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 ...

'' Sesarma''. They included five

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

: ''S. atrorubens'', ''S. impressus'', ''S. intermedius'', ''S. mindanaoensis'', ''S. sinensis''. Serène and Soh defined ''Sesarmops'' as having (1) the

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

as long or longer than the width measured at the external orbital teeth, (2) the frontal margin has a deep median concavity, (3) the postfrontal lobes are prominent, (4) the external orbital tooth is clearly separated from the rest of the lateral margin by a distinct cleft, (5) with the

gastric The stomach is a muscular, hollow organ in the upper gastrointestinal tract of humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical terms re ...

and cardiac regions well defined. Ng et al. provisionally added ''Sesarma weberi'' in 2008, Paulay and Starmer (2011) transferred ''Sesarma angustifrons'' to the genus in 2011. As a culmination of work through the 2000s and 2010s, the genus was revised in January and December 2020. Species were split and redefined, while two species were transferred to a new genus. The type species ''Sesarmops impressum'' (formerly ''Sesarma impressa'') and related species were reviewed by Ng et al. in 2020. ''S. impressa'' ''sensu lato'' from the West Pacific have different colouration and

gonopod Gonopods are specialized appendages of various arthropods used in reproduction or egg-laying. In males, they facilitate the transfer of sperm from male to female during mating, and thus are a type of intromittent organ. In crustaceans and millipe ...

s to those of the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

. Ng, Li, & Shih restricted ''S. impressesus'' to the West Indian Ocean populations, defining ''S. indicus'' in the East Indian and ''S. imperator'' in the

West Pacific 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 the definition, to Antarctica in the south, and is bounded by the continen ...

oceans. The type locality for ''S. indicus'' is the

Andaman Islands The Andaman Islands () are an archipelago, made up of 200 islands, in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a mari ...

, records from northern

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

Mentawai Islands Regency The Mentawai Islands Regency is a Regency (Indonesia), regency of West Sumatra Province which consists of a chain of about a hundred islands and islets approximately off the western coast of Sumatra in Indonesia. They cover a land area of and h ...

, and

Enggano Island Enggano Island (''Pulau Enggano'') is about southwest of Sumatra, Indonesia. It is one of the 92 officially listed outlying islands of Indonesia, though it can also be considered a barrier island of Sumatra. Geography Enggano (from Portugue ...

s are provisionally referred to as the same species. Hess's original types, from "Sydney", for ''S. atrorubens'' and ''S. similis'' are lost. Scholars believe that he received the specimens via

Sydney Sydney is the capital city of the States and territories of Australia, state of New South Wales and the List of cities in Australia by population, most populous city in Australia. Located on Australia's east coast, the metropolis surrounds Syd ...

, and that they were collected elsewhere. Ng et al. designated neotypes from

Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...

and

Samoa Samoa, officially the Independent State of Samoa and known until 1997 as Western Samoa, is an island country in Polynesia, part of Oceania, in the South Pacific Ocean. It consists of two main islands (Savai'i and Upolu), two smaller, inhabited ...

, respectively. Comparisons of

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

found that ''S. impressus'' and ''S. imperator'' form a

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

sister to ''Bresedium eurypleon'' and ''B. brevipes'', indicating that ''Sesarmops'' is

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

to

'. ''S. mora'' is sister to the impressum–Bresidium clade, whilst the ''Sesarmops intermedius'' complex, ''Pseudosesarma patshuni'', and the ''Chiromantes dehaani'' complex form another grouping. ''S. mindanaoensis'' was found to be more distantly related than the other ''Pseudosesarma'' species (''edwardsii, boucourtii, crassimarum''). The latter group (''intermedius–patshuni–dehaani'') was re-classified into a new genus '' Orisarma'' by Schubart & Ng (2020), having five species.

Species

As at 2023, the

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 ...

recognises 9 species of ''Sesarmops'', with two former species moved to ''Orisarma''. * '' Sesarmops angustifrons'' ( A. Milne-Edwards, 1869) * '' Sesarmops atrorubens'' (1865) –

. * '' Sesarmops imperator'' Ng, Li & Shih, 2020 – East Asia to

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

and

Ryukyus The , also known as the or the , are a chain of Japanese islands that stretch southwest from Kyushu to Taiwan: the Ryukyu Islands are divided into the Satsunan Islands ( Ōsumi, Tokara and Amami) and Okinawa Prefecture ( Daitō, Miyako, Y ...

. * '' Sesarmops impressus'' ( H. Milne Edwards, 1837) –

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

Comoros The Comoros, officially the Union of the Comoros, is an archipelagic country made up of three islands in Southeastern Africa, located at the northern end of the Mozambique Channel in the Indian Ocean. Its capital and largest city is Moroni, ...

Mayotte Mayotte ( ; , ; , ; , ), officially the Department of Mayotte (), is an Overseas France, overseas Overseas departments and regions of France, department and region and single territorial collectivity of France. It is one of the Overseas departm ...

. * '' Sesarmops indicus'' Ng, Li & Shih, 2020 –

. Possibly north

and nearby islands. * '' Sesarmops mindanaoensis'' ( Rathbun, 1914) – Taiwan ( Pingtung) and

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

(

Cebu Cebu ( ; ), officially the Province of Cebu (; ), is a province of the Philippines located in the Central Visayas region, and consists of a main island and 167 surrounding islands and islets. The coastal zone of Cebu is identified as a ...

and

Bohol Bohol (), officially the Province of Bohol (; ), is an island province of the Philippines located in the Central Visayas Regions of the Philippines, region, consisting of the island itself and 75 minor surrounding islands. It is home to Bohola ...

) * '' Sesarmops mora'' Li, Shih & Ng, 2020 – Taiwan (Pingtung), Philippines (Cebu and Bohol), Indonesia (

Sulawesi Sulawesi ( ), also known as Celebes ( ), is an island in Indonesia. One of the four Greater Sunda Islands, and the List of islands by area, world's 11th-largest island, it is situated east of Borneo, west of the Maluku Islands, and south of Min ...

and

Manado Manado (, ) is the capital City status in Indonesia, city of the Indonesian Provinces of Indonesia, province of North Sulawesi. It is the second largest city in Sulawesi after Makassar, with the 2020 census giving a population of 451,916,Badan ...

) * '' Sesarmops similis'' (Hess, 1865) –

. * '' Sesarmops sinensis'' = ''Orisarma sinense'' ( H. Milne Edwards, 1853) * '' Sesarmops weberi'' ( De Man, 1892)

References

{{improve categories, date=November 2023 Sesarmidae Decapod genera Terrestrial crustaceans