Leodamas dubia ( Tebble, 1955 )

Zhadan, Anna, Stupnikova, Alexandra & Neretina, Tatiana, 2015, Orbiniidae (Annelida: Errantia) from Lizard Island, Great Barrier Reef, Australia with notes on orbiniid phylogeny, Zootaxa 4019 (1), pp. 773-801 : 789-797

Leodamas dubia ( Tebble, 1955)

( Figs 7 , 8 , 12 C)

Scoloplos dubia Tebble, 1955: 123 –124, fig. 26a–c.

Scoloplos (Leodamas) rubra australiensis Hartmann-Schröder, 1979: 131 –132, figs 276–282. Scoloplos (Leodamas) dubia— Eibye-Jacobsen 2002: 89 –91, fig. 8A–D.

Material examined. AM W.44579, MI QLD 2422 (3); AM W.46094, MI QLD 2429 (10, 1 photographed); AM W.44762, MI QLD 2429 (5); AM W.44765, MI QLD 2429 (photographed); AM W.44765.001, tissue for molecular study; AM W.46098, MI QLD 2439 (7, 1 photographed); AM W.45478, MI QLD 2439; AM W.45478.001, tissue for molecular study; AM W.45479, MI QLD 2438 (photographed); AM W.45479.001, tissue for molecular study; AM W.45480, MI QLD 2376; AM W.45480.001, tissue for molecular study; AM W.44941, MI QLD 2438, posterior fragments.

Description. Body long, slender; thorax flattened dorso-ventrally; abdomen cylindrical ( Figs 7 A–C, 8A, B). Colour in life pale yellowish in thorax, in abdomen more saturated yellow, with red blood vessels, chaetae golden ( Fig. 12 C). Thoracic width up to 1.1 mm. 15–19 (usually 16–18) thoracic chaetigers. Branchiae starting from chaetiger 6, digitiform, gradually increasing in size; becoming triangular with drawn-up tip, longer and wider than notopodia in abdomen ( Figs 7 A, D, E, H, 8F, K). Thoracic post-chaetal lobes developed from chaetiger 2 ( Fig. 7 B). Notopodial lobes digitate, increasing in length along thorax; in abdomen becoming triangular or lanceolate, slightly shorter than branchiae ( Figs 7 A, B, D, E, G, H, 8C, F, K). Thoracic neuropodial postchaetal lobes represented by low ridges; triangular foot papilla of last one or two thoracic chaetigers shifted to upper side ( Figs7 B, С, F, G, 8A– D). Abdominal neuropodial lobes rectangular, bilobed, supported by thick, curved, projecting acicula; with digitate outer lobe and reduced inner lobe ( Figs 7 H, I, 8F, G). Parapodial flange not developed. No subpodal, stomach or flange papillae. Dorsal organs as short curved strips seen in each segment dorsally ( Fig. 7 D). Notopodia bearing crenulated capillary chaetae in both thorax and abdomen; abdominal notopodia additionally having forked chaetae with equal tines and pointed tips ( Fig. 8 J). Thoracic neuropodia with four rows of straight hooded slightly serrated hooks; hooks in anterior row shorter and thicker than in posterior ones; upper hooks thicker than lower ( Figs 7 B, C, F, G, 8C–E); two or three crenulated capillary chaetae located in upper part of posterior row ( Figs 7 B, C, F, G, 8C– E). Abdominal neuropodia with crenulated capillary chaetae and very thick projecting acicula; its shape vary from almost straight to bent almost 180° ( Figs 7 I–K, 8G–I). Pygidium with four short cirri, one pair ventrolateral and the other lateral ( Fig. 8 K).

Remarks. Leodamas dubia was originally described from the Gold Coast ( Ghana, West Africa) as Scoloplos dubia . The species was characterized by having 21–23 thoracic chaetigers, branchiae starting from chaetiger 7, and hooked aciculae in abdominal neuropodia. Eibye-Jacobsen (2002) described numerous specimens from the Thai sector of the Andaman Sea, which he referred to this species. Thai specimens had 18–21 thoracic chaetigers and differed from original description by branchiae starting from chaetiger 6 and shape of abdominal notopodial lobes. Eibye-Jacobsen (2002) also synonymized S. (L.) rubra australiensis Hartmann-Schröder, 1979 with S. (L.) dubia based on the characteristic hooked shape of the neuropodial aciculae. Specimens reported here correspond well to descriptions by Eibye-Jacobsen (2002) and Hartmann-Schröder (1979) and differ by having a lower number of thoracic chaetigers (15–19 instead of 18–21 and 23). As noted for specimens from the Andaman Sea, worms from Lizard Island exhibit large variability in the shape of neuropodial aciculae; they can be almost straight, slightly bent or curved almost 180°. Hence, for correct identification of this species it is necessary to check parapodia from certain abdominal region (20th–45th abdominal chaetigers according to Eibye-Jacobsen (2002)). Otherwise specimens could be referred to other species of Leodamas , i.e., L. rubra ( Webster, 1879) differing mainly by less curved aciculae.

There is a possibility that West-African and Indo-Pacific populations of L. dubia represent different species as they show important morphological differences. To resolve this issue further investigations are needed.

Molecular analyses. The 18S and 16S sequence analyses ( Figs 13 , 14 ) indicated that Leodamas dubia belongs in the clade that consists of L. rubra and L. johnstonei . This clade also includes Leitoscoloplos bifurcatus . As mentioned above, morphologically Leodamas and Leitoscoloplos are very different from each other and molecular analysis contradicts morphological data. The genetic distance between L. rubra and L. dubia is less than 2% for 18S sequences and approximately 10% for 16S sequences. The analysis of orbiniid phylogeny performed by Bleidorn et al. (2009) showed that L. rubra and L. johnstonei form a clade that is a sister clade to all other orbiniid species, but in our trees species of Leodamas did not form sister group to other orbiniids.

abdominal notopodia; K. Regenerating posterior end with pygidium. Genus Naineris Blainville, 1828

Nais Fabricius, 1780: 315 –316.

Naineris Blainville, 1828: 490 –491.

Nainereis .— Hartman 1957: 296; Pettibone 1957: 160.6

Type-species. Nais quadricuspida Fabricius, 1780 , by original designation.

Diagnosis. Prostomium rounded to square in front; one achaetous peristomial ring. Thoracic neurochaetae may include crenulate capillaries, hooks and subuluncini, or crenulate capillaries only, abdominal furcate notochaetae present or absent. First pair of branchiae starting on any thoracic chaetiger from 2 to 23, branchial bases widely separated mid-dorsally. Thoracic neuropodia with 0–2 podal papillae; subpodal papillae and interramal cirri absent.

close-up of lower part with hooks and capillaries; G. Abdominal parapodia; H. Abdominal neuropodia. Naineris grubei australis Hartman, 1957

( Figs 9–11 , 12 D)

Naineris grubei australis Hartman, 1957: 303 –304, pl. 39, figs 1–4.

Naineris grubei australis .— Day 1977: 238; Hutchings & Rainer 1979: 761; Hartmann-Schröder 1980: 66.

between bases of branchiae; G. Close-up view of abdomen, note ciliated ridge (cr) and dorsal organs (do).

Material examined. AM W.44763, MI QLD 2429 (photographed); AM W.44763.001, tissue for molecular study; AM W.44038, MI QLD 2340 (photographed, juvenile).

grubei australis (?), juvenile. Photo: Alexander Semenov.

Description. Body long, cylindrical, thorax slightly flattened ( Fig. 9 A, B). Prostomium broad rectangular.

Thorax 1.6 mm wide for 43 thoracic chaetigers. Branchiae from chaetiger 6, well developed from beginning, triangular with narrow slender tips; in posterior thorax and abdomen becoming longer than notopodia ( Figs 9 A, C, G, 10A, B, F); on each segment two branchiae widely separated mid-dorsally and connected by raised ciliated ridge ( Fig. 10 F, G). Postchaetal parapodial lobes developed from chaetiger 1. Thoracic notopodial lobes triangular with narrow slender tips, in abdomen narrow digitiform ( Figs 9 D, G, 10A, F). Thoracic neuropodial lobes represented by postchaetal ridge with round or elongated papilla; in anterior thorax papilla located in middle of ridge, in middle and posterior part shifted dorsally ( Figs 9 C–F, 10A). Abdominal neuropodia with long triangular outer lobe and reduced round inner lobe, supported by 3–5 aciculae ( Figs 9 G, H, 10B). No subpodal flange, interramal cirri, subpodal or stomach papillae. Dorsal organs represented by five pairs of ciliated spots in each segment ( Fig. 10 G). All notochaetae crenulate capillaries, in both thorax and abdomen. Thoracic neurochaetae of three kinds: capillaries, subuluncini with thick base and sharply tapering tips, and straight, hooded hooks located mostly in lower part of neuropodia ( Figs 9 D–F, 10A, C, D). Abdominal neuropodial lobes supported by 3–4 projecting straight serrated aciculae ( Figs 9 H, 10E). Posterior end unknown.

Juvenile specimen ( Fig. 11 A–C) similar to the description above in prostomial shape, segment of branchiae start, shape of branchiae and podial lobes. It has only 18 thoracic chaetigers, and a thoracic width of 0.8 mm, and most probably belongs to the same species. Colouration in life white, pale yellowish, with brown dots (statocysts) near bases of each branchia in thorax ( Fig. 12 D).

Remarks. Naineris grubei australis was described from the vicinity of Adelaide, South Australia, and later was found in Victoria, New South Wales, and Western Australia ( Hutchings & Rainer 1979; Hutchings & Murray 1984; Hartmann-Schröder 1980). Specimens reported herein agree well with the previous descriptions. The present study expands the distribution of this species to Queensland.

Molecular analyses. According to sequencing data for 18S rRNA ( Fig. 13 ) and 16S rRNA gene fragments ( Fig. 14 ) of Naineris grubei australis , this species belongs in an unresolved clade that contains all Nainereis species and also all Phylo and Orbinia species as well as Orbiniella plumisetosa , Methanoaricia dendrobranchiata , Scoloplos normalis , Scoloplos dayi and Leodamas tribulosus . The sequencing data for the CO1 fragment ( Fig. 15 ) indicates that Naineris grubei australis belongs in a separate group with another Naineris species and Protoaricia oerstedii ; however, this group lacks support (51%).

Figures

FIGURE 7. Leodamas dubia, A – D: methylene blue staining. A. AM W. 44765, anterior end, left lateral view; B. AM W. 45479, anterior end, left lateral view; C. AM W. 45479, thorax-abdomen transition; D. AM W. 44765, abdomen, dorsal view, note dorsal organs (do). E – K: Glycerol mounts of parapodia. E. AM W. 46094, parapodium of chaetiger 17; F. Same, close-up of neuropodia; G. AM W. 46094, parapodium of chaetiger 18; H. AM W. 46098, abdominal parapodia; I. AM W. 44765, abdominal neuropodia; J. AM W. 44765, neuropodial acicula; K. AM W. 45478, neuropodial acicula.

FIGURE 8. Leodamas dubia, AM W. 46094, SEM images. A. Anterior end, dorso-ventral view; B. Thorax-abdomen transition; C. Neuropodia of chaetigers 16 and 17, arrows indicate lateral organs; D. Neuropodium of chaetiger 15; E. Neuropodial hooks of chaetiger 15; F. Abdomen, dorsal view; G – I. Abdominal neuropodia with a variety of aciculae shapes; J. Forked chaetae of

FIGURE 9. Naineris grubei australis, AM W. 44763. A – C: methylene blue staining. A, B. General view; C. Thorax-abdomen transition; D – H: Glycerol mounts of parapodia. D. Chaetiger 13; E. Same, close-up of upper part with subuluncini; F. Same,

FIGURE 10. Naineris grubei australis, AM W. 44763, SEM images. A. Thoracic parapodia, anterior view; B. Abdominal parapodia, anterior view of outer neuropodial lobe; C. Thoracic neuropodial hooks; D. Thoracic neuropodial subuluncini and capillary chaetae; E. Abdominal neuropodial aciculae and capillary chaetae; F. Abdomen, dorsal view, note ciliated ridge (cr)

FIGURE 11. Naineris grubei australis (?), juvenile, AM W. 44038, methylene blue staining. A. Dorsal general view; B. General lateral view; C. Thorax-abdomen transition.

FIGURE 12. Photographs of live specimens. A. Scoloplos acutissimus; B. Scoloplos dayi; C. Leodamas dubia; D. Naineris

FIGURE 13. Neighbor-Joining phylogenetic tree of 53 specimens based on 18 S gene sequences (Table 2). The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. Statistical support for clades in the tree was assessed using the bootstrap analysis with 1,000 replicates.

FIGURE 14. Neighbor-Joining phylogenetic tree of 55 specimens based on 16 S gene sequences (Table 2). The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. Statistical support for clades in the tree was assessed using the bootstrap analysis with 1,000 replicates.

FIGURE 15. Neighbor-Joining phylogenetic tree of 106 specimens based on CO 1 gene sequences (Table 2). The tree is drawn to scale, with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. Statistical support for clades in the tree was assessed using the bootstrap analysis with 1,000 replicates.