Chrysaora agulhensis, Ras & Neethling & Engelbrecht & Morandini & Bayha & Skrypzeck & Gibbons, 2020

Ras, V., Neethling, S., Engelbrecht, A., Morandini, A. C., Bayha, K. M., Skrypzeck, H. & Gibbons, M. J., 2020, There are three species of Chrysaora (Scyphozoa: Discomedusae) in the Benguela upwelling ecosystem, not two, Zootaxa 4778 (3), pp. 401-438 : 416-419

SPECIES Chrysaora agulhensis sp. nov.

[ FIGS 3 a–e; 4a–d; 5; 6]

Type material. Holotype: South Africa: False Bay : MB-A088455 (14.8 cm in diameter, 22 June 2014, preserved in 5% formaldehyde in ambient seawater, Fish Hoek beach, South Africa, opposite train station (34.14°S 18.43°E), V. Ras col.) . Paratypes: South Africa: False Bay : MB-A088456 (~ 12 cm in diameter, 22 April 2014, preserved in 5% formaldehyde in ambient seawater, Fish Hoek beach, South Africa, opposite train station (34.14°S, 18.43°E), V. Ras col.); False Bay: MB-A088457 (~ 13 cm in diameter, 13 November 2012, preserved in 5% formaldehyde in ambient seawater, Whale Rock off Robben Island, South Africa, D. Cox col. (33.81°S, 18.37°E).

Examined material: Holotype: (MB-A088455). Paratypes: (MB-A088456); (MB-A088457). Seven specimens collected by boat at Whale Rock off Robben Island in November 2012 (33.81°S, 18.37°E) ; 11 beach stranded specimens collected at Muizenberg in April 2014 (34.11°S, 18.47°E) (MB-A088458); Four specimens collected by net at Gouritzmond in October 2014 (34.35°S, 21.89°E); Ten stranded specimens collected at Zewenwacht Beach in March 2011 (34.11°S, 18.79°E); Five ephyrae (MB-A088460) and five polyps (MB-A088459) obtained following the settlement of planulae from specimens of medusa collected at Whale rock off Robben Island ; Three medusae from False Bay, collected in 2012 (34.13°S, 18.44°E: 34.10°S, 18.48°E) .

Type locality. Fish Hoek beach, False Bay, Cape Town, South Africa.

Distribution. Range stretches from Table Bay along the west coast of South Africa towards Port Elizabeth along the south east coast of South Africa (Agulhas Bank): endemic.

Diagnosis. Chrysaora of medium size; 32 rounded marginal lappets, four per octant; no more than 24 persistent tentacles; tentacles laterally flattened with pronounced bases, and ribbon-like; oral arms longer than bell, folded spirally at base; characteristic star shape pattern on exumbrella surface always visible, created by the radial pat- tern of deep maroon/purple triangles; white spots scattered across the surface of the exumbrella; mouth becomes substantially larger as organism grows. Lappets with network of gastrovascular canals. Oral arms spirally arranged basally.

Holotype description. Umbrella hemispherical in shape, diameter 14.8 cm. Exumbrella with small raised nematocyst warts, slightly granular, translucent brown in colour (preserved) ( Fig. 4a ), with 16 elongated triangles extending outward from central apex on bell; apices of triangles pointed toward central apex ( Fig. 4a ); colouration of triangles alternate between darker brown pigmentation and little to no pigmentation, forming characteristic starshaped pattern; central apex visible as an unpigmented, translucent circle ( Fig. 4a ); white spots scattered throughout exumbrellar due to raised nematocyst warts. Umbrella centrally thickened; central mesoglea 3.5 x thicker than margin. Umbrella margin cleft into 32 rounded lappets, four lappets per octant: two rhopalial lappets situated next to rhopalium and two velar lappets situated between rhopalial lappets ( Fig. 4c ). Rhopalial lappets not as wide as velar lappets, thus velar lappets appearing elongated while rhopalial lappets appear pointed; lappets equally pigmented on upper and lower surface, appearing dark brown.

Rhopalia: eight rhophalia situated in deep clefts between adjacent rhopalial lappets, project from margin of umbrella into rhopalar canal. Rhopalium protected by sensory niche and an extension from subumbrellar margin forms a protective layer or “hood” above rhopalium ( Fig. 4d ). Base of rhopalium attached to a ridge, running to proximal wall of sensory niche. Thickened endoderm covers surface of sensory niche on subumbrella, thickest along proximal wall ( Fig. 4e ). Thickened endoderm extends outwards for short distance (equal in length to rhopalar canal) (Appendix 3) alongside lappets. Deep, cone shaped sensory pit situated above rhopalium. Rhopalium itself consists of a statocyst, ( Figs 4 d–e) and short, hollow, basal stem (approximately equal in length to statocyst) (Appendix 3). Basal stem clasped by subumbrellar bulb and receives rhopalial canal which is approximately twice as long as the statocyst ( Figs 4 d–e, Appendix 3). No ocelli observed.

One primary tentacle found in each octant, located in clefts between adjacent velar lappets, with two well-developed secondary tentacles situated in clefts between adjacent velar and rhopalial lappets (arrangement 2:1:2), for a total of 24 tentacles ( Fig. 4c ). Tentacles laterally flattened (not circular), solid in cross-section and “ribbon-like”; tentacles less pigmented on ventral surface and cream in colour, light brown on dorsal surface; tentacles cream and unpigmented at base, becoming more pigmented distally and light brown toward tentacle tip. Subumbrella translucent white and smooth; gastrovascular pouches covering central stomach granular ( Fig. 4c ); radial septa arise from periphery of central stomach, dividing gastrovascular cavity into 16 pouches; septa span entire length of circular muscle and fuse at periphery of rhopalial lappets; tentacular pouches dilate and contract distally; rhopalial pouches contract and dilate distally. Manubrium and gastrovascular pouches cream in colour; manubrium arising from central stomach forms thin, tubular, slightly elongated structure with thickened mesoglea; oral opening (mouth) cruciform and situated in centre of manubrium; manubrium wall divided into four oral arms distally. Oral arms cream and translucent ( Fig. 4b ), lancelet-shaped, with distal portion of oral arm much thinner than proximal and central portion; V-shaped in cross section; oral arms spiralled proximally, becoming less spiralled distally; oral arms 15% longer than bell diameter. Basal portion of manubrium fused and thickened to form four gonadal pouches with four oval orifices or ostia situated between them ( Fig. 4c ); gonads attached to periphery of ostia and highly folded/convoluted into semi-circular shape; one ostia situated between two adjacent gonads. No sperm sacs, quadralinga or gastric cirri observed.

Figures

FIGURE 3. Rooted Bayesian species tree for the concatenated nuclear dataset of 18S, ITS1, ITS2 and 5.8S based on the GTR+I+G model of evolution. Posterior probabilities (BY) and bootstrap support values (ML) are given above and below branches respectively. Dotted lines indicate alternative topologies present in Maximum Likelihood analyses. Estimated divergence times, as determined by a time calibrated (RelTime) analysis, are represented on nodes as MYA.

FIGURE 4. Photographs of the Holotype specimen (MB-A088455) of Chrysaora agulhensis sp. nov. submitted to the South African Natural History Museum, collected at False Bay (Fish Hoek), South Africa in June 2014, showing a) the exumbrellar surface with characteristic star-shaped colouration and b) the subumbrellar surface showing colour and length of the oral arms, colour of manubrium as well as the shape of the velar and rhopalial lappets. The shape of the tentacular and rhopalial pouches, showing radial septum fusing at periphery of rhopalial lappets can also be seen in this image. In c) the arrangement of the primary and secondary tentacles (2:1:2) are shown, with the shape and size of the ostia also clearly visible. Enlarged images of the rhopalium which illustrates: d) the ventral view showing the hood and e) the dorsal view showing the statocyst and rhopalal canal.