Laodicea undulata (Forbes & Godsir, 1853)

Schuchert, Peter & Collins, Richard, 2021, Hydromedusae observed during night dives in the Gulf Stream, Revue suisse de Zoologie 128 (2), pp. 237-356 : 279-281

Laodicea undulata (Forbes & Godsir, 1853)

Fig 27 A-E

Laodicea undulata . – Schuchert, 2017a: 353, fig. 2A-C, redescription, complete synonymy.

Examined material: BFLA3797 ; 1 specimen; 13-OCT- 2018; size 6 mm; preserved in alcohol for DNA extraction; 16S sequence MW528645 . – BFLA3806 ; 1 specimen; 19-OCT-2018; preserved in alcohol for DNA extraction; 16S sequence MW528646 . – BFLA3812 ; 1 specimen; 20-OCT-2018; size 8 mm; preserved in alcohol for DNA extraction; 16S sequence MW528647 . – BFLA3836 ; 1 specimen; 19-NOV-2018; size 6 mm; preserved in alcohol for DNA extraction; 16S sequence MW528648 . – BFLA4126 ; 1 specimen; 06-JUN-2019; size 10 mm; has one branched radial canal, thus 5 radial canals in total; preserved in alcohol for DNA extraction; 16S sequence identical to MW528648 . – 04-MAR- 2019; 1 specimen photographed, with one radial canal joining another radial canal instead of manubrium, not collected.

Observations: Laodicea medusae with umbrella up to 10 mm wide, all individuals not fully grown; stomach quadratic, short, with four folded lips. Gonads contiguous with stomach and spreading along proximal half to 2/3 (depending on bell size and age) of widened radial canals (= basal stomach pouches or extensions), flat leaf-like, pendant, sinuous. Up to 100 tentacles; small tentacle bulbs that taper gradually into tentacle, bulb usually with an adaxial ocellus, usually one marginal cirrus between successive tentacles; usually one cordylus between successive tentacles.

16S Data: A blastn search in GenBank with the four obtained sequences gave always as best match one of the European Laodicea undulate sequences, although the similarities were rather low (92-95%). The haplotypes from Florida showed high divergence values of up to 10.6% ( Table 1 ), while the three European haplotypes have only 0.5% bp differences. A maximum likelihood tree separated the sequenced into three distinct lineages ( Fig. 28 ).

Distribution: Eastern Atlantic and adjacent waters from Iceland and northern Norway to South Africa; western Atlantic from Nova Scotia to Tierra del Fuego; Mediterranean ( Kramp, 1968). Some occasional records from the Indo-Pacific require a re-evaluation ( Schuchert, 2017a). Type locality: The Minch, Scotland.

Remarks: It is arguable if the widened radial canals with the gonads ( Fig. 27 ) should not better be interpreted as basal perradial extensions or pouches of the manubrium.

Although the animals of this study were morphologically not separable, some of their 16S sequences were very divergent, suggesting the presence of cryptic species ( Fig. 28 ). Laodicea undulata has a complex synonymy. It includes also a nominal species of the NE Atlantic, namely Laodicea calcarata L. Agassiz, 1862 (see Agassiz, 1865), but this nominal species is currently not separable from L. undulata (comp. Cornelius, 1995; Schuchert, 2017a). Mayer (1900) described Laodicea neptuna from Florida. As it has only eight tentacles it cannot be one of the Laodicea observed here. Kramp (1959a) regarded it as a species inquirenda.

Figures

Fig. 27. Laodicea undulata, all not fully grown. (A-B) BFLA3836, size 6 mm, subadult. (A) Lateral view of whole animal, bell contracted and therefore higher than when relaxed. (B) Aboral view showing bell margin, cirri and cordyli are visible. (C) BFLA3836, size 6 mm. (D) BFLA3812, size 8 mm. (E) BFLA4126, size 10 mm, note the aberrant, branched radial canal.

Fig. 28. 16S maximum likelihood phylogenetictree of Laodiceidae,Hebellidae,and Orchistomatidae,obtainedwith PhyML (GTR+G+I model) and based on about 600 bp positions of the mitochondrial 16S gene. Node-support values are bootstrap values of 100 pseudoreplicates (shown only if> 70%).All sequence labels start with the GenBank numbers (except for identical haplotypes) permitting the retrieval of more information. Red labels are new sequences from this study.