Chelonibia testudinaria ( Linnaeus, 1758 )

Chelonibia testudinaria ( Linnaeus, 1758)

Host and location: Portunus pelagicus, Ha Long and

Kien Giang, new record for Vietnam.

Material examined and measured. Ten live specimens, including 4 specimens from a female crab (87 mm CW, 25 August 2016, locality Ha Long, collector T. Q. Sang) and 6 from a male crab (100 mm CW, 14 May 2016, locality Kien Giang, same collector) .

Morphological description ( Fig.2A–D View Figure 2 ). Shell conical or evenly rounded, heavy, flat and smooth with a diameter of 7.09 ± 4.75 (1 – 15) mm (n = 10), with 6 calcium plates (1 carina, 1 rostrum, and 4 lateral), solidly joined with each other forming a hard shell surrounding the body. The orifice opening 3.33 ± 1.98 (0.5 – 6) mm long (n = 10), partially covered by 2 tergum and 2 triangular patella ( Fig. 2A View Figure 2 ). Dwarf males found settled on the plates and are distributed randomly ( Fig. 2B View Figure 2 ).

Infestation status. Chelonibia testudinaria is recorded as a moderately abundant species (Prevalence 14.82%, mean intensity 9.32 ± 9.96 ( Tab. 1)) and it occupied the outer surface (carapace and limbs), and inside of the sternum ( Fig. 2C, D View Figure 2 ).

Remarks: Chelonibia testudinaria is well-known as a successful generalist epibiotic barnacle. It is found on a wide range of marine hosts. Three species of Chelonibia Leach, 1817 have been described: C. testudinaria on sea turtles ( Rawson et al., 2003; Zardus and Hadfield, 2004; Cheang et al., 2013), Chelonibia manati Gruvel, 1903 on Sirenians, and Chelonibia patula ( Ranzani, 1818) on crustaceans, e.g. blue crab ( Frazier and Margaritoulis, 1990; Bakır et al., 2010; Udoh and Otoh, 2017). Based on genetic characteristics, these three species were later identified as morphotypes of the same species and synonymized under C. testudinaria (see Cheang et al., 2013; Zardus et al., 2014). Geographically, specific clades were also detected for C. testudinaria throughout its distribution range such as in the Atlantic, Indian - West Pacific, and Eastern Pacific Oceans ( Rawson et al., 2003; Zardus et al., 2014). Chelonibia testudinaria was previously recorded on Portunus pelagicus (see Pasternak et al., 2002; Bakır et al., 2010; Babu et al., 2012; Sami, 2018); this, however, is the first record in Vietnam.