Armandia bifida, Parapar, Julio & Moreira, Juan, 2015

Parapar, Julio & Moreira, Juan, 2015, Six new species of the genus Armandia Filippi, 1861 (Polychaeta, Opheliidae) from Lizard Island (Great Barrier Reef, Australia), Zootaxa 4019 (1), pp. 577-603 : 579-582

publication ID

https://doi.org/ 10.11646/zootaxa.4019.1.19

publication LSID

lsid:zoobank.org:pub:C06C733D-924E-4124-AECA-E5C094C9E588

DOI

https://doi.org/10.5281/zenodo.6119358

persistent identifier

https://treatment.plazi.org/id/0397507C-833B-FFE6-5BB7-6E6B83274F61

treatment provided by

Plazi

scientific name

Armandia bifida
status

sp. nov.

Armandia bifida View in CoL n. sp.

( Figs 1 View FIGURE 1 B, 2A–B, 3, 18B)

Material examined. Two specimens in two samples. Holotype: AM W.44696, MI QLD 2366. Paratype: AM W.44117, MI QLD 2422.

Diagnosis. Parapodia biramous, with prechaetal lobe and ventral lobe; anterior parapodial prechaetal lobe notoriously elongated and symmetrically biramous in chaetigers 1 to 3; following chaetigers lacking dorsal ramus and becoming asymmetrically uniramous towards body end. Anal tube somewhat narrower at base and slightly increasing in width towards distal end, becoming tube-like shape; tube opening slightly laterally compressed, directed posteroventrally; posterior border provided with 10–12 pairs of short paired cirri and an internal short anal cirrus.

Description. Based on holotype. Specimen complete, 29.0 mm long and 2.5 mm wide, with 39 chaetigers. Body slender, slightly tapering towards anterior and posterior ends. Prostomium conical ( Figs 2 View FIGURE 2 A, 3A) excluding palpode, longer than wide; palpode very short. A pair of small red eyes deeply embedded in prostomium. One pair of ring-shaped nuchal organs ( Fig. 3 View FIGURE 3 A); pharynx eversible ( Fig. 2 View FIGURE 2 A) provided with several oral tentacles. Branchiae present from CH 2 to last body chaetiger ( CH 39), long, not decreasing in length towards posterior chaetigers, not meeting middorsally ( Figs 2 View FIGURE 2 A–B, 3A–C); branchiae of last chaetigers with brown spots at midlength/distal third. Parapodia biramous, with prechaetal lobe and ventral lobe on each parapodium. Anterior parapodial prechaetal lobe notoriously elongated and symmetrically biramous in CH 1– CH 3 ( Fig. 3 View FIGURE 3 A, D–E); following chaetigers lacking dorsal ramus and becoming asymmetrically uniramous towards body end ( Fig. 3 View FIGURE 3 F–I). Ventral ramus of prechaetal lobe with two conspicuous notches in CH 2– CH 6 ( Fig. 3 View FIGURE 3 E–G). Elongated ventral lobe in all chaetigers; dorsal cirrus not present. Simple capillary chaetae in two bundles; notochaetae slightly longer than neurochaetae, of same length in all chaetigers and about as long as branchiae. Lateral eyespots anterior to parapodia on 11 chaetigers ( CH 7– CH 17), orange, horizontally oval; eyespots of CH 7 and CH 15– CH 17 much smaller than others. Anal tube somewhat narrower at base and slightly increasing in width towards distal end, becoming tube-like shape ( Figs 2 View FIGURE 2 B, 3B–C), as long as last 5–6 chaetigers. Anal tube opening slightly laterally compressed, directed postero-ventrally, appearing obliquely truncate in lateral view ( Fig. 3 View FIGURE 3 C). Posterior border provided with 10–12 pairs of short paired cirri, about 1/10 as long as anal tube, and an internal, unpaired anal cirrus, short and thin, not easily visible through tube wall ( Fig. 3 View FIGURE 3 C). Pair of short basal cirri not observed.

Remarks. Armandia bifida n. sp. is characterised by: 1) the large body size and the large number of chaetigers (39); 2) the bifid shape of the prechaetal lobe in CH 1– CH 3; 3) the presence of branchiae from CH 2 to the last chaetiger, and 4) the distinct tubular, distally-truncated shape of the anal tube. The photograph of the paratype AM W.44696 ( Fig. 2 View FIGURE 2 A–B) when still alive shows the pharynx extruded with at least 12 oral tentacles of same length in a continuous series. Once the specimen was fixed, only three tentacles could be seen externally. Gallardo (1967) illustrates the oral tentacles of A. leptocirris (Grube, 1878) and A. longicaudata ( Caullery, 1944) found at the Nha Trang Bay, South Vietnam. That paper was also unique in providing a key for opheliids mostly based on the shape and number of the afore-mentioned tentacles instead of using the shape of the anal tube ( Gallardo 1967). However, the usefulness of oral tentacles as discriminating character at the species level is doubtful because either needs the observation of live specimens or dissection of fixed material. On the other hand, the paratype AM W.44696 also shows the same number of chaetigers (39), bears brown spots on branchiae in the last segments and the lateral eyes have the same distribution as in the holotype. The specimen bears an internal long unpaired anal cirrus which seems to have been lost in the holotype (dotted line in Fig. 3 View FIGURE 3 C).

Armandia bifida View in CoL n. sp. is similar to Armandia longicaudata View in CoL ( Caullery, 1944, as Ammotrypane View in CoL ) from Java ( Figs 17 View FIGURE 17 G, 18B), and later reported in South Vietnam ( Gallardo 1967), South Africa ( Fig. 17 View FIGURE 17 H) ( Day 1967) and the Solomon Islands ( Gibbs 1971) ( Fig. 18 View FIGURE 18. A B). This species shares with A. bifida View in CoL n. sp. the presence of an elongated prechaetal lobe, which is about as long as the branchiae in the specimens from East Indies ( Caullery 1944, Fig. 35A) and slightly shorter than those from South Africa ( Day 1967, Fig. 25.2.a); this lobe is, however, not bifid as occurs in A. bifida View in CoL n. sp. The anal tube is longer in Caullery’s specimens ( Caullery 1944, Fig. 35B) than in South Africa specimens ( Day 1967, Fig. 25.2.c), which is, in turn, similar to that of A. bifida View in CoL n. sp. The original description of A. longicaudata View in CoL ( Fig. 17 View FIGURE 17 G) mentions paired anal cirri similar to those of A. bifida View in CoL n. sp. while in A. longicaudata sensu Day View in CoL ( Fig. 17 View FIGURE 17 H) they are much larger. Therefore, we suspect that South African specimens may correspond to a different, still undescribed species.

Etymology. The epithet bifida (L.) refers to the conspicuous bifid shape of the prechaetal lobes of the first three chaetigers.

Habitat / Distribution. Intertidal (0–1.5 m) in sandy bottoms off Casuarina beach , in front of Lizard Island Research Station (LIRS) ( Fig. 1 View FIGURE 1 B).

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Family

Opheliidae

Genus

Armandia

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