Actinodendron arboreum
Creators: name: Raghunathan, C.
name: Choudhury, Smitanjali
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Actiniaria
Actinodendridae
Actinodendron
Actinodendron arboreum

description: Actinodendron arboreum (Quoy & Gaimard, 1833), Figure 2.
Synonyms
Actinia arborea Quoy & Gaimard, 1833 (Original description)
Acremodactyla ambonensis Kwietniewski, 1897
Actinodendron ambonense (Kwietniewski, 1897) Actinodendron ambonensis (Kwietniewski, 1897) Actinodendron arborea Quoy & Gaimard, 1833 Actinodendrum arboreum de Blainville, 1830
Material Examined: One specimen collected from Neil Island (Lat. 11°50.939’N; Long: 93°01.207’E), at the depth of 10 m on 18.VIII.2015. Registration No. ZSI/ ANRC -14114.
Description: The pedal disc is well developed with 7.5 mm diameter. Column is smooth. When fully expanded, the oral disc is spread with long tentacles (11.73 mm in length and 2 mm in width), about 12-36 number with complexly branched (Figure 2a). The specimen resembles like a bush or broccoli (Figure 2a). The tentacles are hexamerously arranged in three cycles (6+12+18=36) (Figure 2a). The branching tentacles are more erect and also covered with numerous acrosphers (0.85 mm in length) (Figure 2b &c). The oral disc diameter is about same length as extended tentacles. The acrosphers and tip of the tentacles are dense with long Basitrich forming nematocyst batteries. The column is buried in the substrate surface leaving only the crown of tentacles branching. Longitudinal muscles of tentacles and radial muscles of oral disc are ectodermal. Two broad siphonglyphs are present. Retractor muscles are very strong. Hence, in case of predator, may disappear in fractions of a second retreating completely into the substrate through a strong contraction. The colour of the specimen is tan or light brown. The vesicles are light brown in colour while, the stalk of tentacles are light green or grey in colour.
Cnidocysts
Cnidocysts contain spirocysts and nematocysts which include microbasic p-mastigophores, basitrichs which were derived from various organs of A. arboreum (Table 1) and all are illustrated in Figure 3.
n= Number of nematocyst measured; N = Number of individuals; Frequency indicated by A= abundant C= common, R=
rare, MPM= Micro basic p-mastigophores; Spirocyst (G) = gracile spirocyst
Habitat: This species mainly lives singly in sandy and rubbles covered bottoms on coral reef (Fautin et al., 2009). The specimen reported from Neil Island was found in sandy area and subsequently it was observed from Oliver Island (Lat. 12°59.731’ N; Long. 092°59.918’ E) in the same substratum.
Distribution: This species is found in Singapore (Ardelean, 2003); Marshall Islands, New Caledonia, Australia, Solomon Islands, New Guinea, Indonesia, Okinawa, Philippines (Fautin, 2008; Fautin et al., 2009), Japan (Uchida and Soyama, 2001).
India: Neil Island, South Andaman and Oliver Island, North Andaman.
Remark: New record to Indian waters
description: Published as part of Raghunathan, C. & Choudhury, Smitanjali, 2017, New distributional records of Actiniarian sea anemones from Andaman and Nicobar Islands, pp. 26 in Records of the Zoological Survey of India 117 (1) on page 26, DOI: 10.26515/rzsi/v117/i1/2017/117280, http://zenodo.org/record/10913646