Dictyocladium reticulatum (Kirchenpauer, 1884), 2003

Galea, Horia R. & Schuchert, Peter, 2019, Some thecate hydroids (Cnidaria: Hydrozoa) from off New Caledonia collected during KANACONO and KANADEEP expeditions of the French Tropical Deep-Sea Benthos Program, European Journal of Taxonomy 562, pp. 1-70 : 42-43

Dictyocladium reticulatum (Kirchenpauer, 1884)

Fig. 15

Dictyocladium reticulatum – Vervoort & Watson 2003: 124 , figs 24E–G, 25A–C.

Material examined

PACIFIC OCEAN • a colony, 3.5× 3.5 cm, with female gonothecae; off New Caledonia, stn DW4725; 22°41′ S, 167°05′ E; 240–256 m; 20 Aug. 2016; KANACONO leg.; a fragment was used for DNA extraction, DNA 1402;voucher MHNG-INVE- 120831; MNHN-IK-2015-405 • four colonies, 2.7× 1.6 cm (without gonothecae), 2.7× 3.8 cm (with female gonothecae), 3 × 2.9 cm (with female gonothecae) and 4× 2.6 cm (with female gonothecae); same collecting data as for preceding; MNHN-IK-2015-405 • a colony, 2.5× 1.7 cm, without gonothecae; off New Caledonia, stn DW4741; 22°52′ S, 167°41′ E; 210 m; 23 Aug. 2016; KANACONO leg.; used as a whole for DNA extraction, DNA 1371; voucher MHNG-INVE- 120832; barcode identifier MK 073094 ; MNHN-IK-2015-406 • three colonies, 4.3× 1.7 cm (without gonothecae), 4× 3.5 cm (with female gonothecae), and 3× 3.3 cm (with female gonothecae, and carrying epizoic Synthecium colony); same collecting data as for preceding; MNHN-IK-2015-406 • four colonies without gonothecae, 4.5 × 4 cm, 1.5× 1 cm, 1.5 × 2 cm, and 2.5× 1 cm, respectively; off New Caledonia, stn CP4674; 22°48′ S, 167°29′ E; 311– 302 m; 13 Aug. 2016; KANACONO leg.; MNHN-IK-2015-407 • a fertile colony, 5.2× 5.5 cm; off New Caledonia, stn DW4743; 22°52′ S, 167°34′ E; 380– 340 m; 23 Aug. 2016; KANACONO leg.; MNHN-IK-2015-468 .

Remarks

The present material agrees in nearly all details with the description given by Vervoort & Watson (2003) of this species. However, some colonies have their stems and the basal part of their lower branches lightly but distinctly fascicled. In addition, examination of many gonothecae (from different colonies) seen in apical view showed that the external ridges are not always spirally arranged, as stated by Vervoort & Watson (2003), but they also form concentric ridges that are perfectly transverse in lateral view. All gonothecae agreed with the supposedly female ones described by these authors, but had up to 14 ridges in material MNHN-IK-2015-405 and up to 20 in material MNHN-IK-2015-406, although any other morphological difference could be noted (e.g., a slenderer appearance, as in the supposedly males described by these authors).

The 16S data (see Fig 20 and the ‘Molecular study’ section) strongly suggest that this species belongs to the Symplectoscyphidae , and not the Sertularidae in the sense of Maronna et al. (2016).

Distribution

Bass Strait, Tasmania ( Vervoort & Watson 2003), New Caledonia (present study).

Figures

Fig. 15. Dictyocladium reticulatim (Kirchenpauer, 1884). A–C. Colony fragment (A), hydrotheca (B), gonotheca (C), all from sample MNHN-IK-2015-405. Scale bars: A = 1 mm; B = 200 µm; C = 500 µm.

Fig. 20 (opposite page). 16S maximum likelihood phylogenetic tree of selected Leptothecata species obtained with PhyML(GTR+G+I model) and based on 622 aligned basepair positions of the mitochondrial 16S gene. Node-support values are bootstrap values of 100 pseudoreplicates (shown only if> 70%). Species treated in this study are in bold. Some family clades with sufficient bootstrap support discussed in the present study are highlighted in blue boxes. N.B.: Two species names were not used as given in GenBank (FJFJ550462 and FN424141), and the reasons are given in the Material and methods section.