Sundathelphusa

Sundathelphusa
Sundathelphusa cagayana specimen Photo: MNHN Photographer:Noémy MOLLARET Licensed under CC BY 4.0
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Brachyura
Family:	Gecarcinucidae
Genus:	Sundathelphusa Bott, 1969
Type species
Parathelphusa grapsoides H. Milne-Edwards, 1853

Sundathelphusa is a genus of freshwater crabs in the family Gecarcinucidae, endemic to the Philippines and parts of Indonesia, including Sulawesi. ^[1] These crabs exhibit remarkable adaptations to diverse freshwater habitats, including caves and montane streams.

Ecology and habitat

Habitat preferences

• Surface-dwelling species: Found in rivers, streams, and swamps (e.g., S. Cagayana in Luzon island). ^[2]
• Despite being a cave-adapted species: Troglobitic forms like S. spelaeophila do not exhibit reduced eyes and pigmentation. ^[3]
• Montane species: S. cagayana inhabits high-elevation streams in northeastern Luzon. ^[2]

Ecological roles

• Nutrient cycling: Omnivorous, feeding on detritus, algae, and amorphous. ^[4]

• Bioindicators: Sensitive to water pollution and habitat degradation. ^[4]

Behavior

• Nocturnal activity: Most species forage at night to avoid predators. ^[4]
• Burrowing: Construct burrows in muddy banks for shelter and reproduction. ^[5]

• Reproduction: Direct development (no larval stage); females carry eggs under the abdomen. ^[2]
• Cave adaptations: Troglobitic species rely on special adaptations due to reduced vision. ^[3]

Taxonomy and species

Distinction from Parathelphusa

• Morphology: Sundathelphusa has elongate ambulatory legs compared to Parathelphusa . ^[5]

• Distribution: Sundathelphusa is restricted to the Philippines and Sulawesi, while Parathelphusa occurs in mainland Southeast Asia. ^[1]

Species

• Sundathelphusa currently has the following species: ^[1]
• Sundathelphusa angelito Ng & Mendoza, 2020
• Sundathelphusa antipoloensis (Rathbun, 1904)
• Sundathelphusa aruana (Roux, 1911)
• Sundathelphusa boex Ng & Sket, 1996
• Sundathelphusa cagayana Mendoza & Naruse, 2010
• Sundathelphusa cassiope (De Man, 1902)
• Sundathelphusa cavernicola (Takeda, 1983)
• Sundathelphusa cebu Husana & Ng, 2019
• Sundathelphusa celer (Ng, 1991)
• Sundathelphusa danae Husana, Yamamuro & Ng, 2014
• Sundathelphusa grapsoides (H. Milne Edwards, 1853)
• Sundathelphusa hades Takeda & Ng, 2001
• Sundathelphusa halmaherensis (De Man, 1902)
• Sundathelphusa holthuisi Ng, 2010
• Sundathelphusa jagori (von Martens, 1868)
• Sundathelphusa lobo Husana, Naruse & Kase, 2009
• Sundathelphusa longipes (Balss, 1937)
• Sundathelphusa miguelito Mendoza & Sy, 2017
• Sundathelphusa minahassae (Schenkel, 1902)
• Sundathelphusa mistio (Rathbun, 1904)
• Sundathelphusa molluscivora Schubart & Ng, 2008
• Sundathelphusa montana (Bürger, 1894)
• Sundathelphusa montanoanus (Rathbun, 1904)
• Sundathelphusa niwangtiil Husana, Kase & Mendoza, 2015
• Sundathelphusa orsoni Husana, Kase & Mendoza, 2015
• Sundathelphusa philippina (von Martens, 1868)
• Sundathelphusa picta (von Martens, 1868)
• Sundathelphusa prosperidad Husana, 2020
• Sundathelphusa quirino Husana & Ng, 2019
• Sundathelphusa roberti Ng & Mendoza, 2024
• Sundathelphusa rubra (Schenkel, 1902)
• Sundathelphusa sottoae Ng & Sket, 1996
• Sundathelphusa subquadratus (Gerstaecker, 1856)
• Sundathelphusa sutteri (Bott, 1970)
• Sundathelphusa tuerkayi Ng & Anker, 2016
• Sundathelphusa urichi Ng & Sket, 1996
• Sundathelphusa uva Ng & Mendoza, 2020
• Sundathelphusa vedeniki Ng & Sket, 1996
• Sundathelphusa vienae Husana, Yamamuro & Ng, 2014
• Sundathelphusa waray Husana, Naruse & Kase, 2009
• Sundathelphusa wolterecki (Balss, 1937)
• Sundathelphusa aspera Ng & Stuebing, 1989 synonymous to Borneosa aspera (Ng & Stuebing, 1989)
• Sundathelphusa brachyphallus Ng, 2015 synonymous to Borneosa brachyphallus (Ng, 2015)
• Sundathelphusa spelaeophila Stasolla, Abbarchi & Innocenti, 2015 synonymous to Sundathelphusa philippina (von Martens, 1868)
• Sundathelphusa tenebrosa Holthuis, 1979 synonymous to Borneosa tenebrosa Holthuis, 1979

Conservation

Threats

• Habitat loss due to deforestation, mining, and urban development. ^{[6] [7]}
• Pollution of freshwater ecosystems. ^{[6] [7]}
• Introduction of invasive species. ^{[6] [7]}

References

1. "Sundathelphusa Bott, 1969". World Register of Marine Species. Retrieved 2025-04-10.
2. Mendoza, Jose C. (2010). "A New Species of Riverine Crab of the Genus Sundathelphusa Bott, 1969 (Decapoda: Brachyura: Gecarcinucidae) from Panay Island, Philippines" (PDF). Philippine Journal of Science. 139 (1): 61–70. Retrieved 15 April 2025.
3. Stasolla, D.; Abbarchi, L.; Innocenti, G. (2015). "A new cave-dwelling Sundathelphusa from the Philippines" (PDF). Raffles Bulletin of Zoology. 63: 448–453.
4. Molina, Ziljih S. (2020). "Body Size, Habitat, and Diet of Freshwater Crab Isolapotamon mindanaoense and Sundathelphusa miguelito (Crustacea: Brachyura) in the Municipality of Lake Sebu, South Cotabato, Philippines". Science Diliman. 32 (1): 68–87. Retrieved 15 April 2025.
5. Ng, Peter K. L. (2001). "A Revision of the Genus Sundathelphusa Bott, 1969 (Decapoda: Brachyura: Gecarcinucidae) from the Philippines" (PDF). Zoological Society of Japan. 18: 1123–1127. Retrieved 15 April 2025.
6. Cumberlidge, Neil (2009). "Freshwater crabs and the biodiversity crisis: Importance, threats, status, and conservation challenges" (PDF). Biological Conservation. 142 (8): 1665–1673. doi:10.1016/j.biocon.2009.02.038.
7. Husana, Daniel Edison M. (2020). "Sundathelphusa prosperidad, sp. n. (Decapoda: Brachyura: Gecarcinucidae), a new cave-obligate freshwater crab from Mindanao Island, the Philippines, with notes on the conservation status of Philippine cave species" (PDF). Journal of Cave and Karst Studies. 82 (3): 210–218. doi:10.4311/2019LSC0116.

External links

• GBIF: Sundathelphusa – Global Biodiversity Information Facility
• WoRMS: Sundathelphusa – World Register of Marine Species
• Media related to Sundathelphusa at Wikimedia Commons