Armandia aff. weissenbornii Kükenthal, 1887

Parapar, Julio, Al-Kandari, Manal & Moreira, Juan, 2025, The genus Armandia Filippi, 1861 (Annelida, Opheliidae) on the coast of Kuwait and Saudi Arabia, Zootaxa 5728 (1), pp. 107-143 : 124-139

Armandia aff. weissenbornii Kükenthal, 1887

Figures 1 , 11D , 12 , 18 ; Table 1

Armandia weissenbornii Kükenthal, 1887: 366-368 , figs 6-7.

Armandia weissenbornii Kükenthal – Amoureux 1983a: 738 , figs 6-9.

Material examined. Two specimens from one sample collected in the littoral of Saudi Arabia ( Fig. 1 , Tab. 1) .

Diagnosis. Parapodia biramous, with prechaetal lobe, ventral lobe and dorsal cirrus. Prechaetal lobe about 1/3 of branchial length in CH 1 and progressively decreasing in length till body end. Lateral eyespots from CH 6 to CH 27/28. Branchiae from CH 2 to last chaetiger. Anal tube about three times as long as wide, spoon-shaped, with wide dorsal incision extending about half tube length and to posterior margin; posterior margin provided with 5–6 pairs of marginal papillae and unpaired anal cirrus; no ventral incision.

Description. Specimens 21.0 and 11.2 mm long, 1.0 and 0.5 mm wide respectively, both with 32 chaetigers. Prostomium conical, palpode short and clavate ( Fig. 18A ). Prostomial eyes not seen. One pair of ring-shaped nuchal organs ( Fig. 18A ); pharynx not seen. Parapodia biramous, with prechaetal lobe, ventral lobe and dorsal cirrus ( Fig. 18B–G ). Prechaetal lobe long in CH 1 about as long as CH 2 branchiae ( Fig. 18B ); decreasing in length progressively from CH 1 to CH 8–10 ( Fig. 18C–F ), about 1/10 of branchial length in CH 10, then becoming much shorter towards body end ( Fig. 18G ). Dorsal cirrus globose from CH 1 to about CH 17 ( Fig. 18B–F ). Lateral eyespots anterior to parapodia on 20 chaetigers ( CH 6– CH 27/28) ( Fig. 18A ); circular, those of CH 6 and CH 16– CH 27/28 much smaller. Simple, very long capillary chaetae in two bundles; notochaetae longer than neurochaetae. Ventral groove deep, well defined along the body. Branchiae present from CH 2 to last chaetiger ( Fig. 18A–H ), long, almost reaching body dorsal midline, not decreasing in length in posterior chaetigers. Anal tube only present in small specimen; as long as last 4 chaetigers, about three times as long as wide ( Fig. 18H–I ). Anal tube opening directed posteriorly and dorsally; wide dorsal incision extending posteriorly about tube dorsal distal half ( Fig. 18H ). One short, pointed marginal papilla still present; ringed unpaired anal cirrus, about as long as anal tube ( Fig. 18H–I ). No ventral incision.

Variation. Number of chaetigers and parapodial prechaetal lobe size and distribution are similar in the two examined specimens.

Distribution / Habitat. Armandia weissenbornii was originally described from the Perim Island (Gulf of Aden, Red Sea; Kükenthal 1887) ( Fig. 12 ). Posteriorly, Amoureux (1983a) described specimens attributed to this species from the Gulf of Aqaba (Red Sea); this record is later mentioned by Hartman (1959, 1974), Amoureux (1983b), Wehe & Fiege (2002), Le Garrec (2013) and Pamungkas & Glasby (2019). The two specimens studied in this work have been collected in shallow subtidal sand in Ras az-Zawr ( Tab. 1).

Remarks. Armandia weissenbornii is characterised by the following diagnostic features, which were fully observed in Kuwait specimens: 1) 32 chaetigers, 2) long parapodial lobes in anterior chaetigers, 3) branchiae from CH 2 to last chaetiger, 4) anal tube with 5–6 pairs of marginal papillae and ringed unpaired anal cirrus ( Kükenthal 1887; Amoureux 1983a).

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The characteristic length and shape of the parapodial lobe of A. weissenbornii is a conspicuous feature of this species, quite resembling a second branchia per parapodium as stated by Amoureux (1983a, p. 727): “ au point de ressembler une branchie en position plus ventrale que la branchie véritable ”. A few Indopacific species also show long and/or large parapodial lobes at least in the first chaetigers, namely Armandia bifida Parapar & Moreira, 2015 , A. casuarina , A. laminosa and A. mariacapae . Regarding A. laminosa , the lobe is foliose instead of triangular and not much longer than wide; this shape is restricted to the first three chaetigers ( Parapar & Moreira 2015: figs 7A, C-E, 8D, 9E). In A. bifida , parapodial lobes in the first three chaetigers are long but bifid appearing symmetrically biramous ( Parapar & Moreira 2015: fig. 3A, D-E). On the contrary, A. casuarina bears only a long parapodial lobe in CH 1 which decreases in length in the following two chaetigers. Finally, in A. mariacapae parapodial lobes are triangular and longer than wide in all chaetigers but comparatively shorter than in A. weissenbornii ( Moreira & Parapar 2017: fig. 6B-F).

The anal tube is spoon-shaped and bears a long dorso-terminal opening that is not explicitly mentioned in the original description or by Amoureux (1983a) but illustrated by the latter in figure 7 (see also atdi in Fig. 11D ). Regarding anal papillae, Kükenthal (1887) states that these are as long as last four chaetigers and refers just a few small papillae (“ einigen sehr kleinen Papillen ”, p. 368) while Amoureux (1983a) mentions 5–6 papillae that according to the illustration seem to number up to 10 (5 pairs). In several species of Armandia , the anal tube is also provided with a wide opening as A. weissenbornii . In A. bifida and Armandia sampadae Gopal et al., 2016 , the opening is ventro-posterior instead of dorso-posterior; the marginal papillae are much smaller in A. bifida ( Parapar & Moreira 2015: fig. 3B-C) while A. sampadae bears papillae that are much longer instead and lacks the unpaired anal cirrus ( Fig. 11A ). A. casuarina and A. mariacapae bear two types of anal papillae ( Moreira & Parapar 2017: fig. 5B-C and fig. 6G, respectively) and in A. mariacapae the anal tube opening is restricted to the terminal margin. The extension of the anal opening in A. simodaensis Takahashi, 1938 ( Japan) is similar to that of A. weissenbornii but the anal tube is longer (as long as 8–10 last chaetigers) and lacks anal papillae and cirrus ( Takahashi 1938: fig. 1, 2; Fig. 11C ); Takahashi (1938) also mentions the presence of “long subulate dorsal parapodial cirrus” (not illustrated) and fewer numbers of chaetigers (28 vs 32) and pairs of branchiae (26 vs 31) and lateral eyes (10 vs 20).

Regarding specimens from Kuwait, these show slight differences in lateral eyespots with previous descriptions. According to Kükenthal (1887), there are 13 pairs of eyespots ( CH 9– CH 21), that are smaller between CH 16 and CH 21 while Amoureux (1983a) mentions 12 pairs beginning in CH 7. On the other hand, differences in number of anal papillae might be due to the state of preservation. Therefore, the aforementioned peculiar shape and length of the parapodial lobe present in Kuwait specimens suggests that these belong to A. weissenbornii . However, we cannot confirm this possibility due to the limited number of specimens available, the scarcity of reports and descriptions for this species and the potential presence of other unknown species with similar parapodia. These specimens were previously reported by Fiege (1992) as Armandia longicaudata , which is now placed in Ophelina due to the absence of lateral eyespots ( Neave & Glasby 2013; Parapar et al. 2023). In addition, in O. longicaudata the anal tube is longer, and the opening is restricted to the posterior margin ( Caullery 1944: fig. 35).

Figures

FIGURE 1. Sampling localities in the coast of Kuwait where specimens of Armandia studied in this work were collected; colours showing range of abundance.

FIGURE 11. Line drawings of posterior body region of several Armandia species. (A) A. sampadae (redrawn from Gopal et al. 2016); (B) A. sinaitica (redrawn from Amoureux 1983a); (C) A. simodaensis (redrawn from Takahashi 1938); (D) A. weissenbornii (redrawn from Amoureux 1983). Abbreviations: ata = anal tube annulations; atdi = anal tube dorsal incision; br = branchia; CH = chaetiger; pbp = paired basal papillae; pmp = paired marginal papillae; uac = unpaired anal cirrus.

FIGURE 12. Map of Indian Ocean andWest Pacific Ocean showing the type locality and records of Armandia species previously reported in the Arabian Gulf (following Parapar et al. 2021b), complemented with the type locality of other taxa described in the area. 1—A. sampadae Gopal et al. 2016; 2—A. andamana (Grube, 1878); 3—A. exigua Kükenthal, 1887; 4—A. simodaensis Takahashi, 1938 and A. amakusaensis Saito et al., 2000; 5—A. broomensis Hartmann-Schröder, 1979; 6—A. bifida Parapar & Moreira, 2015, A. dolio Parapar & Moreira, 2015, A. filibranchia Parapar & Moreira, 2015, A. laminosa Parapar & Moreira, 2015, A. paraintermedia Parapar & Moreira, 2015, A. tubulata Parapar & Moreira, 2015, A. buccina Moreira & Parapar, 2017, A. casuarina Moreira & Parapar, 2017, A. mariacapae Moreira & Parapar, 2017, A. opisthoculata Moreira & Parapar, 2017 and A. parva Moreira & Parapar, 2017; 7—A. secundariopapillata Hartmann-Schröder, 1984; 8—A. bilobata Hartmann-Schröder, 1986.

FIGURE 18. Armandia aff. weissenbornii Kükenthal, 1887. Line drawings of two specimens (SMF 11513: A–G = larger specimen; H–I = shorter specimen). (A) anterior end, left side, lateral view; (B–G) parapodia, left side (B–D, G = lateral view; E–F dorsal view): CH1 (B), CH2 (C), CH3 (D), CH8 (E), CH10 (F) and CH32 (G); (H) posterior end, dorsal view slightly displaced to the right; (I) posterior end, lateral view. C = only proximal part of long chaetae drawn. D–G = chaetae not drawn. Abbreviations: atdi = anal tube dorsal incision (each pair of arrows delimiting extension of incision to left and right respectively); br = branchia; CH = chaetiger; le = lateral eyespot; nec = neurochaetae; noc = notochaetae; nuo = nuchal organ; pcl = prechaetal lobe; pdc = parapodial dorsal cirrus; pmp = paired marginal papillae; pp = palpophore; ps = palpostyle; pvl = parapodial ventral lobe; uac = unpaired anal cirrus. B–G = same scale.