Armandia circumpapillata, Magalhães & Rizzo & Bailey-Brock, 2019

Magalhães, Wagner F., Rizzo, Alexandra E. & Bailey-Brock, Julie H., 2019, Opheliidae (Annelida: Polychaeta) from the western Pacific islands, including five new species, Zootaxa 4555 (2), pp. 209-235 : 215-218

Armandia circumpapillata sp. nov.

Figures 1 (D), 5 (A–C) and 6 (A–E)

Material examined. Holotype: Hawaii, Oahu, Waianae ocean outfall, Sta. W 2R2, 21°24'46.5" N, 158°11'45.6" W, May /2015, 27.7 m ( BPBM-R3883 ) ; Paratypes: same station, date and collector as holotype (2 spms, BPBM- R3884). Additional material: Oahu , Hawaii : Waianae ocean outfall, Sta. W 2R2, 21°24'46.5" N, 158°11'45.6" W, May /2015, 27.7 m (2 spms on SEM stub); Waianae ocean outfall, Jun/2014, Sta. W 2R3, 21°24'46.5" N, 158°11'45.6" W, 27 m (3 spms); May/2015, Sta. W 9R6, 21°26'29.4" N, 158°12'16.3" W, 33 m (4); Sta. ZWR5, 21°25'25" N, 158°11'55.4" W, 34 m (1). Barbers Point ocean outfall, Sept/2014, Sta. HB 2R5, 21°17'00.4" N, 158°01'21.5" W, 59.4 m (3); Sta. HB 2R3, 21°17'00.4" N, 158°01'21.4" W, 59.4 m (4). Mokapu ocean outfall, Oct/ 2013, Sta. DR 2, 21°25'32.3" N, 157°42'53.6" W, 60 m (7). Sand Island ocean outfall, Oct/2014, Sta. D 3AR1, 21°16'55.4" N, 157°53'49.2" W, 50 m (5); Sand Island ocean outfall, Oct/2015, Sta. D 2R1, 21°16'56.8" N, 157°54'35.6" W, 53.3 m (7); Sta. E 3R2, 21°16'44.0" N, 157°53'48.9" W, 82.3 m (1); Sta. D 3AR2, 21°16'55.5" N, 157°53'49.3" W, 50.9 m (4); about 1 km offshore Waikiki, Sta. SE, Feb /2016, coll. M. Hixon (5).

Diagnosis. Parapodia biramous, with parapodial prechaetal lobe and ventral lobe, lacking dorsal cirrus. Anal tube short, slightly narrower distally, with up to six transversal striations; up to seven pairs of round, short marginal papillae with gradation of length; internal, unpaired ventral anal cirrus, long and crenulated; one pair of glandular, digitate and wide basal papillae.

Description. Holotype 6 mm long and 0.5 mm wide for 27 chaetigers. Paratypes 5.5–7.4 mm long and 0.4–0.7 mm wide for 26–27 chaetigers. Body slender, slightly tapering towards anterior and posterior ends ( Fig. 6A ). Prostomium elongate, excluding palpode, longer than wide; palpode elongate, clavate ( Figs 5A ; 6B ). A pair of small brownish eyes deeply and ventrally embedded in prostomium present; dorsal eye also small. One pair of oval-shaped nuchal organs on deep ciliated pits, posterior to eyespots inserted on posterior margin of prostomium ( Figs 5A ; 6B, C ); pharynx not observed. Branchiae from chaetiger 2 and absent only on last two chaetigers, short, not meeting middorsally, decreasing in length towards posterior chaetigers, last 2–3 chaetigers lacking branchiae ( Figs 5B ; 6A ); branchiae lacking pigmentation.

Parapodia biramous, with parapodial prechaetal lobe, triangular anteriorly and becoming rounded on mid- to posterior body ( Figs 5 A–C; 6D); ventral lobe present, shorter than prechaetal lobe and digitate, similar throughout ( Fig. 6D ); dorsal cirrus absent. Simple capillary chaetae in two bundles; notochaetae twice longer than neurochaetae; notochaetae longer than branchiae throughout and neurochaetae of same length as branchiae from chaetiger 2. Notochaetae and neurochaetae of anterior chaetigers numbering eight capillaries per bundle reducing to 3–5 posteriorly. Lateral eyespots anterior to parapodia 7 on 11 chaetigers (chaetigers 7–17), reddish brown, variable shape, usually bean-shaped to horizontally oval ( Fig. 5A ); eyespots of chaetiger 7, 16, and 17 of about a third the size of others.

Anal tube short, slightly narrower distally, as long as last two chaetigers and with up to six transversal striations ( Figs 5B, C ; 6E ). Posterior border provided with up to seven pairs of round, short papillae (but usually five pairs); marginal papillae with dorsal gradation in length, dorsal-most shorter, ventral-most papillae longer and slightly smaller than paired basal papillae ( Figs 5B, C ; 6E ). Internal, unpaired ventral anal cirrus, long and crenulated ( Figs 5B, C ; 6E ). Pair of glandular, digitate and wide basal papillae, usually larger and distinct from marginal papillae ( Fig. 5B, C ); some individuals presenting dark spots on basal cirri ( Fig. 5B ).

Remarks. Armandia circumpapillata sp. nov. is most similar to specimens identified as Armandia intermedia sensu Day (1967) from South Africa in relation to the shape of the anal cone and marginal papillae. Differences are related to the number of segmental eyes (11 pairs in A. circumpapillata sp. nov. and 12 pairs in A. intermedia sensu Day, 1967 ), 5–7 pairs of marginal anal papillae in A. circumpapillata sp. nov. and 10–20 papillae in A. intermedia sensu Day, 1967 , crenulated unpaired anal cirrus in A. circumpapillata sp. nov. and unpaired anal cirrus being illustrated as smooth in A. intermedia sensu Day, 1967 .

Armandia opisthoculata Moreira & Parapar, 2017 shares some similarities with A. circumpapillata sp. nov. in relation to the shape of the anal tube but differs in respect to the shape and number of paired marginal papillae (up to seven pairs in A. circumpapillata sp. nov. and nine pairs in A. opisthoculata ), length of the unpaired anal cirrus (long in A. circumpapillata sp. nov. and short in A. opisthoculata ). Small reddish spots were described for the paired basal papillae of A. opisthoculata and pigmented spots were also described for the same body region in Armandia sampadae Gopal, Jaleel, Parameswaran & Vijayan, 2016 and to some specimens of A. circumpapillata sp. nov.

Etymology. The epithet circum comes from the Latin for round, and papillata for papillae, referring to the round shape of the anal lateral and basal papillae.

Distribution. The type locality is Waianae, west shore of Oahu, Hawaii. This species has also been collected in Mamala Bay, Kailua Bay, Barbers Point and off Waikiki from shallow subtidal to 82 m depth in sand and coral rubble.

Figures

FIGURE 1. Armandia garretti sp. nov. from Pearl Harbor, Hawaii: A, anterior end of a live specimen showing everted pharynx; B, anal cone in lateral view and C, anal cone in ventral view. Armandia circumpapillata sp. nov. D, anal cone in lateral view.

FIGURE 5. Armandia circumpapillata sp. nov. from Waianae, Hawaii: A, anterior end in lateral view; B, posterior end with pygidium of two individuals in lateral view; C, posterior end with pygidium of two different individuals in ventral view.

FIGURE 6. SEM of Armandia circumpapillata sp. nov. from Waianae, Hawaii: A, complete specimen in lateral view; B, anterior end, dorso-lateral view; C, detail of nuchal organ; D, parapodia of mid-body; E, pygidium in lateral view.