Mastigias papua ( Lesson, 1830 )

Souza, Mariana Rocha De, 2018, Redescription of Mastigias papua (Scyphozoa, Rhizostomeae) with designation of a neotype and recognition of two additional species, Zootaxa 4457 (4), pp. 520-536 : 526-528

Mastigias papua ( Lesson, 1830)

( Figures 4–5 )

Mastigias sp.: Cephea papua Lesson, 1830 ; Haeckel 1880; Vanhöffen 1888; Mastigias physophora Kishinouye, 1895 ; Pseudorhiza thocambaui Agassiz & Mayer, 1899 ; Mastigias papua var. sibogae Maas, 1903 ; Mayer 1910; Stiasny 1920, 1926; Uchida 1926; Kramp 1961; Hamner & Hauri 1981; Hamner 1982; Dawson et al. 2001; Dawson & Hamner 2003; Dawson 2005a, b; Swift et al. 2016.

Type Material. Smithsonian Museum USNM 1486941 (previously M0D001038-X of Dawson collection) neotype: Mastigias Papua Cove, Waigeo Island, West Papua (00 19.356’ S 130 34.277’ E), 21.xi.2007, M0D001038-X, 1 adult medusa (female) preserved in 4% formalin.

Other Material. Scripps Institution of Oceanography / UCSD PIC- 180420 -0001 -PT (previously M0D005690- V of Dawson collection): Mastigias Papua Cove , Waigeo Island , West Papua (00 19.35’ S 130 34.27’ E), 21.xi.2007, adult female medusa preserved in 4% formalin.

California Academy of Sciences CASIZ 219752 (previously M0D005693-Y of Dawson collection), Danau Ctenophore , West Papua (0027.29’ S 13029.58’ E), 26.xi.2007, adult male medusa preserved in 4% formalin.

Michael N Dawson collection MOD05687-S, M0 D05688 -T, M0 D05689 -U, M0 D05691 -W, M0 D05692 -X, M0 D05694 -Z, M0 D05695 -A. Specimens preserved in 4% formaldehyde. Avaliable for examination upon request.

Type Locality: Waigeo Island, West Papua, Indonesia (00 19.356’ S 130 34.277’ E), in agreement with the original type locality reported in Lesson (1830, p 122): “chez les Papous de la Waigiou ( Lesson, 1830, p 122), i.e. the Coast of Waigeo Island,

Distribution: Western Pacific: West Papua, Palau and Marshall Islands.

Diagnosis. Five to ten velar lappets per octant (mean 9.7 ± 1.17 s.d.), 10.8 ±2.3 adradial origins at Gastrovascular Cavity (GVC) per quadrant, oral arms 0.3 ±0.05 times the size of bell diameter (bd; winged part of oral arm 0.21 ±0.05 bd; unwinged part of oral arm 0.10 ±0.03 bd). Thymine at positions 2, 79, 244, 292, 496, 559 and 575; guanine at positions 77, 209, 259, 332 and 409; cytosine at positions 103, 106, 109, 190, 344, 460 and 530 and adenine at positions 94, 199, 202, 205, 424, 512, 547, 550 and 625 of COI (Appendix 1).

Habitat. Medusae planktonic in coastal waters and marine lakes; occasionally oceanic. Usually present near surface (to several meters depth) during the day, deeper (tens of meters) at night. Abundance may vary through the year at and between locations ( Dawson 2005a).

Description of Neotype Specimen of Mastigias papua . Medusa is yellow-brown with white spots of various sizes on the exumbrella ( Fig. 4A, B , 5A ). Bell diameter 122.2 mm. Ring canal about twice the diameter of the oral disc (respectively 104 mm and 49 mm). Mesoglea of the bell flexible, thicker around the center portion, thinning towards bell margin. Velar lappets round ( Fig. 5E ), 80 in the whole medusa (number in each octant: 9, 10, 10, 11), with furrows often between adjacent pairs of lappets. Mean (±s.d.) oral arm length is 43.37± 0.51 mm, with winged portion about 1.5 times longer than unwinged part (respectively 26.65± 1.27 mm and 16.7± 1.07 mm). Four perradial and four interradial rhopalia, each between two pointed rhopaliar lappets. Brood filaments present at the base of the oral arms and oral disc (mature female specimen). Terminal clubs about 1.4 the size of bell diameter (bd; mean 175.42± 6.65 mm) and shaped like a tricorn in cross-section ( Fig. 5B ). Oral pillars 15.05± 0.07 mm wide, 3.68 ± 0.12 mm long and 2.8± 0.14 mm deep. Genital ostia 35.5 ± 0.28 mm wide. Gastrovascular cavity (GVC) with one perradial, one interadial and 7±0.5 adradial origins per octant ( Fig. 5D ). Two perradial, two interadial and 27.5±0.68 adradial anastomoses per octant. One gastrovascular and one adradial sinus, no perradial nor interadial sinuses, per quadrant. One ring canal sinus present in each of 2 quadrants.

Palau and West Papua samples: variation from the type specimen. Ocean samples from West Papua presented terminal club mean 0.86±0.24 bd; interradial diameter of the GVC mean 0.52±0.08 bd, perradial diameter of the GVC 0.21±0.03 bd; 6.5±0.5 mean adradial origins at GVC and 27.2±4.05 mean adradial anastomoses per octant. When compared to lake samples from West Papua, the features presented similar values: terminal club mean 0.83±0.05 bd; interradial diameter of the GVC mean 0.54±0.09 bd, approximately two-and-aquarter times the length of the perradial diameter of the GVC; 6.37±0.58 mean adradial origins at GVC and 23.93± 1.85 mean adradial anastomoses per octant.

Ocean samples from Palau presented terminal club mean 0.67±0.16 bd; interradial diameter of the GVC mean 0.55±0.03 bd, perradial diameter of the GVC mean 0.25±0.04 bd; 6.65±0.33 mean adradial origins at GVC and 48.64±16 mean adradial anastomoses at GVC per octant. Samples from marine lakes from Palau presented interradial diameter of GVC mean 0.54±0.04 bd and perradial diameter of the GVC mean 0.26±0.05 bd; 5±1.02 adradial origins at GVC and 19.36±17.2 adradial anastomoses per octant; and differed from samples from ocean locations in having shorter terminal clubs (terminal club length 0.17±0.11 bd; t = -16.649, df = 155, p-value <0.0001).

Comparison with historical descriptions. Both nMDS analyses visually represent the data reasonably well (stress = 0.11–0.12; Fig. 6 ). In both representations, the new samples from Philippines were close to the historical description for M. albipunctatus ; although the museum sample from Philippines was not close in this representation to the other samples from Philippines. The museum sample from Australia was close in both representations to the historical description of M. sibogae . Samples from Tufi were most similar to the historical descriptions of M. papua , M. ocellatus and M. andersoni ( Fig. 6A ). The geographically distant Mastigias pantherinus , from Samoa Islands, is distinct morphologically from all other samples in both representations.

Figures

FIGURE 4. Mastigias papua from the type locality: waigeo, west Papua (specifically from Mastigias Papua Cove, November 2007) showing ontogenetic variation within species. A. Mature medusa, 150 mm bell diameter B. Juvenile medusa, 16 mm bell diameter. (i) unwinged portion of the oral arm, (ii) winged portion of oral arm, and (iii) terminal club.

FIGURE 5. Adult Mastigias papua medusa (103 mm bell diameter) from the type locality: waigeo, west Papua (specifically from Mastigias Papua Cove). A. Profile view of M. papua, with details of the oral arm and margin of the bell. Two rhopalia are marked with arrows, delineating an octant. B. Details of the subumbrellar view of the terminals clubs, showing the typical ‘tricorn’ cross-section of lagoonal animals. C. Details of the contracted bell margin and oral arm. Note the patches of endosymbiontic zooxanthellae (here most easily visible as tan tiny dots in the unwinged part of oral arm). D. Subumbrellar view of canals dyed in the laboratory, note the perradial canal (p) and the interradial canal (i) which are both generally simple canals originating at the gastrovascular cavity and ending at the ring canal; the origins of the highly anastomosing adradial canals are marked with yellow circles where they join the gastrovascular cavity. E. Subumbrellar view of the bell margin, with velar lappets in between the two pairs of rhopalar lappets (r).

FIGURE 6. nMDS analysis of the morphological variation of Mastigias medusae including data from all historically described species. A. Analysis including Mastigias from both lake (open colored symbols) and ocean (filled colored symbols) samples, and also from historical descriptions (black filled symbols). B. Analysis including only Mastigias from ocean habitats and from the historical descriptions. Circle emphasizes the close morphological match between new samples from the Philippines and historical descriptions of M. albipuntatus.