Pectinaria nusalautensis, Pamungkas & Hutchings, 2023

Pamungkas, Joko & Hutchings, Pat, 2023, Pectinaria nusalautensis (Pectinariidae, Annelida): a new polychaete species from Maluku, Indonesia, Raffles Bulletin of Zoology 71, pp. 1-11 : 2-10

publication ID	https://doi.org/ 10.26107/RBZ-2023-0001
publication LSID	lsid:zoobank.org:pub:C7008EE4-C242-40E0-83B3-4F5A6E367350
persistent identifier	https://treatment.plazi.org/id/F5EB9B99-56E5-4C71-97EC-C5B01D34A2FE
taxon LSID	lsid:zoobank.org:act:F5EB9B99-56E5-4C71-97EC-C5B01D34A2FE
treatment provided by	Felipe
scientific name	Pectinaria nusalautensis
status	sp. nov.

Treatment

Pectinaria nusalautensis View in CoL , new species

( Figs. 2–7 View Fig View Fig View Fig View Fig View Fig View Fig )

Material examined. Holotype: 1 ( MZB. Pol. 00236), intertidal sandy beach of Sila Village, Nusalaut Island , Maluku, 3°38ʹ54.6ʺS, 128°46ʹ7.7ʺE, about 30 cm depth, coll. J. Pamungkas, 5 October 2009. GoogleMaps

Description. Preserved specimen pale cream in colour, complete, measuring 40 mm long by 10 mm wide at anterior part, slightly tapering posteriorly. Body with 26 segments, divided into three distinct sections, i.e., thorax (segments 1–7), abdomen (segments 8–21) and scaphe (segments 22–26) ( Figs. 2 View Fig , 3 View Fig ). Tube cone-shaped, made of cemented shell-like fragments.

Thoracic section comprises opercular and cephalic regions along with appendages, and four achaetous segments (1–4) followed posteriorly by three chaetigerous segments (5–7) ( Figs. 2 View Fig , 3 View Fig ). On dorsal side, opercular rim raised, smooth with surface striations ( Figs. 2A View Fig , 3A View Fig ). Opercular plate more or less circular, smooth with transverse striations ( Figs. 2A View Fig , 3A View Fig ). Two combs of short notopodial paleae present; each comb consists of 12 stout, golden paleae with faint transverse lines and blunt tips. Lateral paleae shortest; length gradually increases towards mid paleae then gradually decreases towards proximal paleae; proximal paleae narrowest ( Figs. 2A View Fig , 3A View Fig , 4A View Fig , 5A View Fig ). On ventral side, rim of cephalic veil cirrate with 25 narrow, elongated, conical cirri ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ). Cephalic veil broad, thin, and completely free from operculum, forming a dorsal semi-circular lobe covering base of numerous non-retractable peristomial palps (buccal tentacles) ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ). Peristomial palps finger-like, grooved and varying in size ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ).

First pair of tentacular cirri small and short, with wide base up to one-third of total length of cirri; cirri arise from anterolateral edge of segment 1, near most lateral notopodial paleae. Second pair of tentacular cirri larger, about three times longer than first pair of cirri; cirri with wide base up to one-third of total length of cirri and present laterally on segment 2 ( Fig. 4A View Fig ). Between two pairs of cirri, one pair of ventral lappets present obliquely on segment 1 ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ). Two pairs of comb-like, stalked branchiae present on segments 3 and 4. Both pairs similar in size, situated laterally lying against body, and consisting of loose flat lamellae; branchiae of segment 3 inserted more ventrally than those of segment 4 ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ). Segment 2 without posterodorsal lobe, but with dorsolateral flaps extending ventrally to ventral flaps ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ) and a mid-ventral triangular glandular area with faint longitudinal striations ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ). Segments 3 and 4 with dorsolateral pads; pad of segment 3 twice as long as those of segment 4 ( Figs. 2A View Fig , 3A View Fig ). A prominent mid-ventral trapezoidal glandular area with smooth surface flanked by two small antero-ventral lobes present on segment 3 ( Figs. 2B View Fig , 3B View Fig , 4A View Fig ). Three large and broad antero-ventral lobes present on segments 4–6; antero-ventral lobe on segment 4 with lateral humps ( Figs. 2B View Fig , 3B View Fig , 4A, B View Fig ). Chaetigers 1 to 3 (segments 5–7) uniramous with notopodia bearing golden flattened capillary chaetae ( Figs. 4B View Fig , 5A View Fig ).

Abdominal section consists of chaetigers 4 to 17 (segments 8–21), with dorsal and ventral areas strongly translucent, with sand grains visible in gut ( Figs. 2 View Fig , 3 View Fig ). Abdominal glandular areas elliptic, present ventrally on all abdominal segments, adjacent to parapodia ( Fig. 3B View Fig ). Chaetigers 4 to 16 biramous with noto- and neuropodia bearing notochaetae and neurochaetae, respectively ( Figs. 2B View Fig , 3B View Fig , 4B View Fig ). Chaetiger 17 uniramous with notopodia bearing notochaetae. Holotype has 17 noto- and 13 neuropodia with uncini (17/13). Notochaetae golden flattened capillaries with wide base tapering distally. Chaetae with smooth margins and bamboo-like when seen under a compound microscope; many of which have broken tips, intact chaetae with pointed tips ( Figs. 6 View Fig , 7A View Fig ). Uncini with major teeth arranged in two longitudinal rows with about 8–10 teeth per row; basal teeth small and difficult to count ( Fig. 7B View Fig ).

Scaphe distinctly separated from abdomen and consisting of last five posterior segments fused. Six pairs of scaphal hooks observed, situated dorsally at attachment region between base of scaphe and last abdominal segment. Scaphal hooks with a broad shaft and a blunt distal end ( Figs. 4C View Fig , 5B View Fig ). Scaphe flattened and diamond-shaped with broad-crenulated margins. A triangular anal flap present posteriorly, smooth with longitudinal striations. Anal cirrus absent ( Figs. 4D View Fig , 5C View Fig ).

Methylene blue staining pattern. Darkest blue areas include cephalic veil cirri, ventral lappets on segment 1, ventral flaps on segment 2, dorsolateral pads on segments 3 and 4, trapezoidal gland along with two flanking ventral lobes on segment 3, antero-ventral lobes on segments 4–6, and transitional region between abdomen and scaphe. Medium blue stained areas include operculum, dorsal regions of segments 2–7, abdominal parapodia, elliptic glandular areas on ventral area of abdominal segments and scaphe. Light blue stained areas include peristomial palps, branchiae, dorsal and ventral regions ( Fig. 3 View Fig ).

Remarks. Pectinaria nusalautensis , new species, can be distinguished from all the other 27 Pectinaria species (WoRMS Editorial Board, 2022) by the combination of the following characters: 12 pairs of golden, stout notopodial paleae with faint transverse lines and blunt distal tips, one pair of ventral lappets on segment 1, one pair of dorsolateral flaps extending ventrally to ventral flaps and one mid-ventral triangular glandular area with faint longitudinal striations on segment 2, two pairs of dorsolateral pads on segments 3 and 4, one prominent mid-ventral trapezoidal glandular area with smooth surface flanked by two small antero-ventral lobes on segment 3, three large and broad antero-ventral lobes on segments 4–6, a strongly translucent abdominal region (this is unlikely due to fixation or preservation as to our best knowledge most of the other 27 Pectinaria species do not show a similar appearance despite being fixed and preserved in the same way), golden flattened and bamboolike noto-capillaries with smooth margins and pointed tips, and a diamond-shaped scaphe with a triangular anal flap.

Pectinaria nusalautensis , new species, most closely resembles the Australian species P. dodeka Hutchings & Peart, 2002 , in terms of the number and the shape of notopodial paleae, the type and the pair number of branchiae as well as their position, and the presence of a mid-ventral triangular glandular area on segment 2 (or according to Zhang & Hutchings, 2019, the glandular area of P. dodeka is situated between segments 2 and 3), dorso-lateral pads on segments 3 and 4, lateral humps on segment 4, and relatively large and broad antero-ventral lobes on segments 4–6 (see all these features in the stained specimen of P. dodeka in Zhang & Hutchings, 2019: fig. 26). Zhang & Hutchings (2019) reexamined the type material and provided details of additional characters which were not described by Hutchings & Peart (2002). Pectinaria dodeka was recorded to occur in the northern area of Australia, adjacent to Indonesian waters, i.e., Arafura Sea ( Hutchings & Peart, 2002). Pectinaria nusalautensis , however, has dorsolateral flaps extending ventrally to ventral flaps on segment 2, which are not present in P. dodeka (see Zhang & Hutchings, 2019: fig. 26B, F). While a mid-ventral trapezoidal glandular area flanked by two small antero-ventral lobes is present on segment 3 in P. nusalautensis , the feature is absent in P. dodeka ; instead, a relatively large lobe is present on segment 3 in the latter species (see Zhang & Hutchings, 2019: fig. 26A, G). The lateral humps of P. nusalautensis are semi-circular, whereas those of P. dodeka are triangular (see Zhang & Hutchings, 2019: fig. 26F, G). The antero-ventral lobes on segments 3–6 in P. nusalautensis are restricted to the anterior side of each segment, whereas in P. dodeka the lobes completely cover the entire segments (see Zhang & Hutchings, 2019: fig. 26A, B, F, G). Pectinaria dodeka has noto-capillaries with one margin strongly pectinated (see Hutchings & Peart, 2002: fig. 11A, B), whereas in P. brevispinis both margins are smooth. Lastly, the scaphe of P. dodeka is oval and flattened with a triangular tongue-like anal flap bearing a single dorsal cirrus (see Hutchings & Peart, 2002: fig. 14B; Zhang & Hutchings, 2019: fig. 26D, E), whereas that of P. nusalautensis is diamond-shaped with a relatively large triangular anal flap without a cirrus.

Pectinaria nusalautensis , new species, also shares similar characteristics with P. brevispinis which was originally described based on a single specimen collected from the Philippines by Grube (1878), and was later reported to occur in Indonesian waters, i.e., on the same island as P. nusalautensis by Caullery (1944). The type specimen of P. brevispinis , which was deposited at the Museum für Naturkunde in Berlin, Germany, has unfortunately been lost (Birger Neuhaus, pers. comm.), making it impossible for the authors to directly compare the morphology of the present specimen with that of the type specimen of the species. Caullery (1944) also did not examine the type specimen of P. brevispinis , so his record of the species must also be regarded as tentative. However, based on the descriptions of P. brevispinis in four publications, i.e., Grube (1878), Nilsson (1928), Caullery (1944), and Hutchings & Peart (2002), although only Nilsson examined the type, we found that both P. brevispinis and P. nusalautensis have a similar number of notopodial paleae, a smooth and slightly wrinkled opercular rim, lateral humps on segment 4, and the same number of rows of major teeth per uncinus. Pectinaria brevispinis , nevertheless, has a heart-shaped opercular plate (see Grube, 1878: pl. XI, fig. 2), whereas the feature is more or less circular in P. nusalautensis . Nilsson (1928) furthermore reported the presence of a mid-ventral granular area in P. brevispinis (see fig. 20A in his paper), whereas the area is smooth with faint longitudinal striations in P. nusalautensis . The antero-ventral lobe on chaetiger 2 in P. brevispinis was not observed by Grube (1878) but is slightly glandular according to Nilsson (1928) and Hutchings & Peart (2002); the lobe is obvious in P. nusalautensis especially when stained. While the dorsum of P. brevispinis shows clear segmentation (see Grube, 1878: pl. XI, fig. 2), the region is smooth and translucent in P. nusalautensis . Nilsson (1928) pointed out two types of capillary chaetae in P. brevispinis (see fig. 20B–E in his paper), whereas P. nusalautensis only has one type of capillaries. The number of pairs of scaphal hooks of P. brevispinis was also reported differently, i.e., 10 pairs according to Grube (1878), 4–6 pairs with blunt tips according to Nilsson (1928) – the author wrote that some hooks have probably fallen out as the cuticle of the type specimen is completely separated and the underlying tissue is very loose – and 8–12 pairs with pointed tips according to Hutchings & Peart (2002). In contrast, P. nusalautensis has six pairs of scaphal hooks with blunt tips. Furthermore, P. brevispinis has an oval scaphe with reduced anal flap, whereas P. nusalautensis has a diamond-shaped scaphe with a triangular anal flap. The body length of P. brevispinis species ranges from 60 to 92 mm ( Hutchings & Peart, 2002), whereas that of P. nusalautensis is only 40 mm. As there are discrepancies between the original description by Grube and the subsequent redescription by Nilsson of the single type specimen, we suggest that P. brevispinis must be considered species inquirenda until additional material from the type locality is collected and a neotype is designated.