Eunice dharastii, Zanol & Hutchings, 2022
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publication ID |
https://dx.doi.org/10.3897/zookeys.1118.86448 |
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publication LSID |
lsid:zoobank.org:pub:AD0EF3AA-6C9A-4988-B69B-FA9D2F6A7E7E |
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persistent identifier |
https://treatment.plazi.org/id/63BC2367-9654-45DA-8021-FD17584DFFDC |
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taxon LSID |
lsid:zoobank.org:act:63BC2367-9654-45DA-8021-FD17584DFFDC |
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treatment provided by |
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scientific name |
Eunice dharastii |
| status |
sp. nov. |
Eunice dharastii sp. nov.
Figs 1 View Figure 1 , 2 View Figure 2
Material examined.
Holotype. Australia • New South Wales, Nelson Bay, Port Stephens Main Beach ; 32°42'54.91"S, 152°9'1.12"E; 8 m depth; Aug. 2012; D. Harasti leg.; AM W.53870 GoogleMaps . Paratype. Australia • 1 same data as for holotype; AM W.41747 GoogleMaps .
Comparative material.
Australia • 1 incomplete with 80 chaetigers, 120 mm in length and 20 mm maximum width Eunice cf. aphroditois ; New South Wales, Nelson Bay, Port Stephens; AM W.140.
Description.
Live specimens: iridescent reddish with lighter patches on prostomium, peristomium, and along the body (Fig. 1A, B View Figure 1 ). Prostomium appendages, peristomial cirri, and notopodial cirri red to brown, uniformly colored, with lighter areas close to proximal half and at distal ends. Dorsal and ventral buccal lips whitish at distal end, standing out from posterior part of prostomium (Fig. 1B View Figure 1 ; see Suppl. material 2).
Fixed specimens iridescent brown to purple with lighter patches. Only peristomial cirri and few notopodial cirri retain color pattern of live specimens, prostomial appendages beige (Fig. 1A-C View Figure 1 ). Specimens are very curled and rigid because of the 95% ethanol fixation, making measurement of length and width difficult.
Holotype incomplete, with 520 chaetigers, in two pieces; first with 300 chaetigers, 200 well preserved + 100 slightly flaccid, and second with 220 chaetigers, all slightly flaccid; total length 980 mm; length through chaetiger 10 20 mm; width at chaetiger 10 without/with parapodia 12/15 mm, maximum width at chaetiger 18 without/with parapodia 18/22 mm, from chaetiger 18 width fairly uniform for following 200 chaetigers. Many parapodia with broken chaetae.
Paratype incomplete with 782 chaetigers in three pieces, first with 250 chaetigers, second with 222, all slightly flaccid, and third with 310 chaetigers; total length 1170 mm; length through chaetiger 10 20 mm; width at chaetiger 10 without/with parapodia 16/19 mm; maximum width at chaetiger 100 without/with parapodia 18/23 mm. Body almost semicircular anteriorly, becoming more flattened around chaetiger 70-80.
Prostomium with dorsal buccal lips as paired median dorsal ridges, obliquely truncate, with thickened lateral margins and median sulcus narrow (Fig. 1B View Figure 1 ). Dark eyes present outside lateral antennae. Median, lateral antennae and palps reaching back, respectively, to chaetigers 4 (9), 5 (9) and at least until middle of first peristomium ring (3) (antennae and palps are very rigid and difficult to manipulate in holotype; measurements are estimates). Prostomial appendages not evenly spaced, palps isolated by a small gap from lateral antennae; arranged in semicircle, palps partially in front of lateral antennae (Fig. 1B View Figure 1 ). Ceratophores of median and lateral antennae and palpophores short and ring-shaped. Ceratostyles of median and lateral antennae and palpostyles irregularly articulated; tapering (Fig. 1E View Figure 1 ). Peristomium cylindrical; separation between first and second rings only visible on dorsal and ventral sides; ventrally second ring much shorter than dorsally (Fig. 1C-E View Figure 1 ). Dorsally first ring 5/6 of total length of peristomium. Ventrolateral lips muscular and inflated (Fig. 1D View Figure 1 ). Peristomial cirri reaching a little more anterior than middle of first peristomial ring; irregularly articulated; tapering (Fig. 1C, E View Figure 1 ).
Maxillary formula 1+1, 7+7, 7+0, 4+7, 1+1, 1+1 (Fig. 2A View Figure 2 ). Carrier with lateral anterior sclerotized margins almost parallel to each other, abrupt tapering after initial 1/3 of its length. MxI about 2.5 times longer than carrier, lacking a curvature at internal basal edge, with a curvature at outer basal edge, falcal arch extended. MxII with teeth distributed along more than half its length, posterior end wide with distinct thickened outer ridge. MxIII short; part of distal arc with left MxIV and V. MxVI ridge like with a narrow distal tooth. Mandibles calcareous cutting plates with ellipsoid shape (Fig. 2B View Figure 2 ).
Branchiae present from 10 (10) until at least chaetiger 520, end of branchiae not recorded (branchiae ends well before pygidium on chaetiger 492); first with just 1 button-shaped filament around 1/5 of dorsal cirri length (Fig. 1H View Figure 1 ), around chaetiger 22 as long as notopodial cirri, number of filaments rapidly increasing to 38 (26); best developed branchiae from about chaetiger 40 through subsequent chaetigers with thick tapering stems, around 2.5 to 4 times longer than longest filament and notopodial cirri (Fig. 1F, J View Figure 1 ); becoming shorter at end of most posterior fragment (becoming shorter at end of distribution).
Chaetal lobes truncate along whole fragment, posterior increasingly oblique; anterior with dorsal fleshy knob and neuroaciculae emerging posterior to it (Fig. 1F, I View Figure 1 ); neuroaciculae near dorsal edge in all parapodia. Prechaetal lobe low transverse fold until end of fragment. Postchaetal lobes round/truncate, longer than chaetal lobe at anterior end (Fig. 1D View Figure 1 ), decreasing along the body, low transverse fold shorter than chaetal lobe by end of fragment. Anteriormost ventral cirri thumb-shaped to tapering, becoming basally inflated from about chaetiger 4 or 5; inflated bases elongate, ridge-like decreasing towards posterior end; free tip round to slightly tapering in all chaetigers, clearly separated from base (Fig. 1D, F View Figure 1 ). Notopodial cirri pendulous, abrupt tapering from inflated bases, irregularly articulated (Fig. 1D-F, H View Figure 1 ).
Slender, tapering limbate chaetae longer than all other chaetae present in all chaetigers. Pectinate chaetae thin anodont with flattened shafts; tapering smoothly subdistally or near proximal end along whole fragment (Fig. 2D, F, G View Figure 2 ). Numbers of teeth variable, 10-14 (N = 21, mode = 11); each tooth flattened, distally tapering abruptly to slender hair-like tip; all with similar lengths. Distal ends of compound falciger chaetae shafts a little wider than proximal ends along whole fragment. Appendages of compound falciger chaetae with variable lengths within a chaetal bundle of anterior parapodia, longest in anterior parapodia; shortest appendages of anterior chaetigers as long as appendages in median and posterior chaetigers, all with similar lengths; bidentate with both teeth directed laterally; both teeth about same length in anterior chaetigers, distal tooth much shorter than proximal tooth in median and posterior chaetigers; guards asymmetrically blunt (Fig. 2H, I View Figure 2 ). Neuroaciculae distinctly dark along all its length, double in most parapodia, some posterior parapodia with single acicula; tapering to blunt or sharp tips (Fig. 1F, G View Figure 1 ). Subacicular hooks present from chaetiger 58 (53); initially one per parapodium, increasing to two, reaching a maximum of four at chaetiger 81 (85) subsequent parapodia with three or four, most posterior with two; distinct, dark along all its length, with distinct dark core and clear sheath at distal end; bidentate tapering to small head, distal tooth minute, spur-like, proximal tooth much larger, both teeth directed distally (Fig. 2C, E View Figure 2 ). In both types many chaetae broken.
Posterior end of body and pygidium missing.
Habitat and specific density.
Water depth, 1-8 m, in tubes in coarse sand substrates; also occurs in sandy habitats to the west and east of the type locality in same depth range. Average specific density in Nelson Bay main beach 3.5 ± 0.6 individuals per 30 m2.
Type locality.
Nelson Bay Main Beach (32°42'54.91"S, 152°9'1.12"E), Port Stephens, New South Wales, Australia.
Etymology.
The species is named in honor of Dr David Harasti, who collected the specimens, donated them to the Australian Museum, and first suspected they were a species new to science.
Remarks.
Eunice dharastii sp. nov. is most similar to E. aphroditois , E. flavopicta Izuka, 1912 and E. kinbergi Ehlers, 1868 in having the prostomium with dorsal buccal lips as paired median dorsal ridges; MxVI present; branchiae longer than notopodial cirri, with stem much longer and thicker than filaments; pectinate chaetae thin anodonts with flattened shafts tapering smoothly subdistally or near proximal end; bidentate compound falcigers, dark paired tapering/blunt neuroaciculae and dark bidentate subacicular hooks ( Izuka 1912; Fauchald 1992). The unique combination of features that characterizes Eunice dharastii sp. nov. and differentiate it from these three species are: irregular articulated prostomial appendages; antennae reaching back beyond chaetiger 4; branchiae starting at chaetiger 10, initially button-shaped; best developed branchiae distinctly longer than notopodial cirri; dorsal fleshy knob on anterior chaetal lobe; notopodial cirri pendulous (sensu Fauchald 1992), abrupt tapering from inflated bases; bidentate compound falciger chaetae with both teeth directed laterally, distal tooth much shorter than proximal tooth in median and posterior chaetigers; and dark bidentate subacicular hooks starting at chaetiger 58, tapering to small head with both teeth directed distally, proximal tooth much larger than minute and spur-like distal tooth (Table 1 View Table 1 ). The unusual shape of the subacicular teeth is shared only with E. aphroditois , E. borneensis Grube, 1878 (type locality North Borneo), and E. mutabilis Gravier, 1900 (type locality Djibouti; Fauchald 1992). The latter two are clearly distinct from E. dharastii sp. nov. in several features, such as the absence of MxVI, shape of branchiae and chaetae.
The examined specimen from Port Stephens identified as E. cf. aphroditois ( Zanol et al. 2020) differs from the new species in the length of the prostomial appendages, median and lateral antennae folding back to chaetiger 1 and palps to the first peristomial ring; and the start of branchiae at chaetiger 11 with five short filaments. Thus, it is here considered a different species. At least three Eunice species live in sympatry in the vicinity of the type locality (Port Stephens), E. cf. aphroditois , E. impexa Grube, 1878 ( Zanol et al. 2020), and E. dharastii sp. nov. Besides E. aphroditois , E. confusus Zanol, Hutchings & Fauchald, 2020 is the most similar species to E. dharastii sp. nov. reported from Australian waters. Nevertheless, they only share a similar shape of the prostomium, peristomium and peristomial cirri, the prostomial appendages are irregularly articulated, maxillary formula (but not shape of plates and carrier), shape of anterior pectinate chaetae and aciculae. Considering previous knowledge on the diversity of morphological features, the observed differences are enough to consider the analyzed specimens a new species to science. Molecular data for this species will be available in a subsequent paper.
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