Prosphaerosyllis modinouae Neal & Paterson, 2020
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publication ID |
https://dx.doi.org/10.3897/zookeys.938.49349 |
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publication LSID |
lsid:zoobank.org:pub:76B7FF03-FEB1-4884-AD29-55BE864F0EBF |
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persistent identifier |
https://treatment.plazi.org/id/4FE5FE0D-7909-40C1-A8AE-F641192A6048 |
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taxon LSID |
lsid:zoobank.org:act:4FE5FE0D-7909-40C1-A8AE-F641192A6048 |
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treatment provided by |
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scientific name |
Prosphaerosyllis modinouae Neal & Paterson |
| status |
sp. nov. |
Prosphaerosyllis modinouae Neal & Paterson sp. nov. Figures 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11 View Figure 11
Materials.
Sample 63MFA, 448 m, -49.2457310, -59.1254934, coll. 17/03/2012, ind. 1, holotype (NHM.2018.25100). Sample 21MFC, 445 m -49.2866453, -59.1130539, coll. 16/04/2012, ind. 1, paratype (NHM.2018.24236). Sample 28MFB, 451 m, -49.3044189, -59.0852225, coll. 23/04/2012, ind. 1, paratype (NHM.2018.24386). Other materials: Sample 15MFB, 454 m, -49.2686572, -59.1133764, coll. 16/04/2012, ind. 1, NHM.2018.24080. Sample 25MFA, 447 m, -49.3050428, -59.1677492, coll. 16/04/2012, ind. 1, NHM.2018.24302. Sample 25MFC, 438 m, -49.3050428, Longitude: -59.1677492, coll. 16/04/2012, ind. 1, NHM.2018.24324. Sample 35MFC, 450 m, -49.3221858, -59.0573711, coll. 15/04/2012, ind. 1, NHM.2018.24498. Sample 40MFA, 450 m, -49.3403947, -59.0845558, coll. 23/04/2012, ind. 1, NHM.2018.24605.Sample 41MFA, 439 m, -49.3401736, -59.0570275, coll. 14/04/2012, ind. 1, NHM.2018.24637. Sample 44MFB, 429 m, -49.3585975, -59.1117606, coll. 14/04/2012, ind. 1, NHM.2018.24719. Sample 60MFC, 450 m, -49.2545270, -59.0494527, coll. 19/03/2012, ind. 1, NHM.2018.25062. Sample 64MFC, 447 m, -49.2455380, -59.1060962, coll. 18/03/2012, ind. 1, NHM.2018.25127. Sample 69MFC, 442 m, -49.2887900, -59.1005700, coll. 19/03/2012, ind. 1, NHM.2018.2521. Comparative materials: Prosphaerosyllis kerguelensis : Kerguelen Islands (off Cumberland Bay), 232 m, -48.750000, -69.233333, holotype, BMNH.85.12.1.155. Sphaerosyllis palpopapillata : Antarctic Peninsula, 300 m, -63.27777778, -63.72166667, holotype, ZMH P-20751.
Description.
Holotype (NHM.2018.25100) a complete, very small, slender specimen, 4.5 mm long and 0.5 mm wide (at mid-body) for 31 chaetigers. Paratype (NHM.2018.24236), complete specimen 2.8 mm long and 0.4 mm wide (at mid-body) for 31 chaetigers. Paratype (SEM specimen, NHM.2018.24386) complete specimen 3.5 mm long and 0.4 mm wide (at mid-body) for 30 chaetigers. Paratype (SEM specimen, NHM.2018.24236) incomplete specimen 1.2 mm long and 0.25 mm wide for 12 chaetigers. Integument of body appearing smooth under light microscopy (Fig. 5a View Figure 5 ), upon staining (Fig. 6a-d View Figure 6 ) and under SEM (Fig. 7a, c, f View Figure 7 ) sparse papillation detected dorsally with two alternating longitudinal rows of digitiform papillae on each side of the body (= 4 rows in total); palps with some diffused small papillae (Fig. 8b View Figure 8 ); papillation on body venter diffused (Fig. 6d View Figure 6 );parapodial with few tiny papillae (Fig. 9d View Figure 9 ); slender and elongated lateral body papillae observed in-between parapodia (Fig. 9b, c View Figure 9 ). Colour in alcohol pale yellow, no pigmentation observed (Fig. 5a View Figure 5 ).
Prostomium short, wider than long (Figs 5b, c View Figure 5 ; 8a View Figure 8 ). Three antennae present (Figs 7d View Figure 7 ; 8a View Figure 8 ), all pyriform and very small (difficult to observe under stereo microscope); median antenna positioned near posterior margin of prostomium, ca. 30 µm long; lateral antennae positioned lateromedially on prostomium, smaller than median antenna, ca. 25 µm long (Figs 7d View Figure 7 ; 8a View Figure 8 ).
Palps very short, almost entirely obscured by prostomium in dorsal view (Figs 5b, c View Figure 5 ; 7a-d View Figure 7 ; 8a View Figure 8 ) with only their lateral margins visible in dorsal view; fully fused along their length; provided with some small papillae (Fig. 8b View Figure 8 ). Two pairsof large red eyes present (Figs 5b-d View Figure 5 ; 8a View Figure 8 ), in trapezoid arrangement, with anterior and posterior pair close together (almost appearing as a single eye), anterior pair cup-shaped, posterior pair circular; presence of additional eyespots not confirmed.
Proventricle starts between chaetigers 3-4 and ends between chaetigers 6-7, with ca. 20 muscle rows (Figs 5b View Figure 5 ; 6b View Figure 6 ). First segment achaetous; with small pair of tentacular cirri, ca. 20 µm long, pyriform (similar to antennae) (Figs 7d View Figure 7 ; 8a View Figure 8 ). Pharynx everted in paratype (NHM.2018.24236) (Fig. 7c, d View Figure 7 ), without terminal papillae, pharyngeal tooth far from anterior margin.
Parapodia uniramous, short but distinct, conical (Fig. 9a-c View Figure 9 ). Dorsal cirri in all chaetigers, including chaetiger 2 (Figs 7e View Figure 7 ; 8a View Figure 8 ) (missing in some parapodia due to damage); dorsal cirri in anterior chaetigers small (but easy to observe, ca. 40 µm in length, Fig. 5e View Figure 5 ), similar in form to tentacular cirri and antennae, becoming more elongated in posterior chaetigers (ca. 55 µm long, Fig. 5f View Figure 5 ). Ventral cirri as extremely slender cirriform structures, inserted near the base of neuropodia (Fig. 9a-c View Figure 9 ), becoming progressively longer posteriorly.
Chaetae often missing (broken off). One simple dorsal chaeta commonly observed (Fig. 10a View Figure 10 ), present from chaetiger 1; straight and smooth; increasing in size throughout body measuring 30 µm in anterior parapodia, 85 µm in mid-body parapodia and 110 µm in some posterior parapodia (Fig. 10b View Figure 10 ). Simple ventral chaeta observed only in posteriormost parapodia, slightly sigmoid and smooth (Fig. 10c View Figure 10 ). Other chaetae compound falcigers (Fig. 10d-g View Figure 10 ); ca. six per fascicle; all blades unidentate and serrated to greater (Fig. 10d, g View Figure 10 ) or lesser degree (Fig. 10e, f View Figure 10 ). Blades of falcigers of varying lengths with greatest length difference between dorsalmost (Fig. 10d View Figure 10 ) and ventral most (Fig. 10e View Figure 10 ) chaetae in anterior parapodia, this difference becomes particularly pronounced in mid-body parapodia, where long dorsalmost chaeta (Fig. 10f View Figure 10 ) bears particularly short blade (as ratio to length of its shaft); length of blades 5-13 µm (total chaetal length 35-60 µm) in anterior chaetigers; 5-13.5 µm (total chaetal length 75-100 µm) in mid-body chaetigers and 12-20 µm (total chaetal length ca.100 µm) in posterior chaetigers (Fig. 10g View Figure 10 ). Acicula in anterior and posterior chaetigers mostly solitary, acuminate (Figs 5g, h View Figure 5 ; 9e View Figure 9 ).
Pygidium broad, rounded, pygidial cirri not observed in any specimens examined (Fig. 5a View Figure 5 ).
Remarks.
Falkland Island specimens were assigned to genus Prosphaerosyllis San Martín, 1984 based on morphological characters only as no reproductive specimens were observed. San Martín (2005) emended the generic diagnosis and further distinguished Prosphaerosyllis from the similar genus Sphaerosyllis , however here we provide a comparison for species in both genera with the type locality inthe southern waters because not all species have been revised. Sphaerosyllis antarctica , S. hirsuta , S. sublaevis , S. capensis , S. dubiosa , S. lateropapillata uteae and Prosphaerosyllis kerguelensis (holotype BMNH.85.12.1.155 examined as part of this study) can be easily distinguished from the Falkland Island species due to absence of dorsal cirrus on chaetiger 2. Of species with a dorsal cirrus on chaetiger 2 present ( S. semiveruccosa , P. joinvillensis , P. capensis chilensis , S. brandhorsti and P. brachycephala ) the new species can be easily distinguished by having small antennae and short palps (often with only their lateral margins observable in dorsal view, otherwise mostly obscured by prostomium).
Falkland Islands species is most similar to P. isabellae De Nogueira, San Martín & Amaral, 2001 described from intertidal depths in Brazil in having short antennae and a sparse distribution of body papillae. However, other than length of the palps, P. modinouae sp. nov. can be further differentiated by having all falcigerousblades serrated (these are smooth from mid-body chaetigers in P. isabellae ), in lacking iridescent inclusions in the dorsal cirri and in the dorsal cirri becoming elongated throughout the body in P. modinouae sp. nov. There also appear to be greater differences in length of falcigerous blades in P. modinouae sp. nov. (Fig. 10d-g View Figure 10 ) compared to P. isabellae (see DeNogueira et al. 2001; Fukuda et al. 2009). We also suggest that Brazilian specimens from bathyal depths assigned to P. isabellae by Fukuda et al. (2009) may in fact represent a different species, even more closely aligned to P. modinouae sp. nov. This suggestion is based mainly on much deeper distribution (down to 650 m) reported by Fukuda et al. (2009) compared to 4-7 m depth at the type locality of P. isabellae , which was also reported to be associated with coral colonies ( De Nogueira et al. 2001). However, specimens of P. isabellae were not available for examination as part of this study.
Another similar species is Sphaerosyllis palpopapillata Hartmann-Schröder & Rosenfeldt, 1992 described from the Antarctic Peninsula, 300 m depth. Unfortunately, the description and drawings provided by Hartmann-Schröder and Rosenfeldt (1992) are of limited value. Therefore, the holotype (ZMH P-20751) was loaned from Zoologisches Museum Hamburg and photographed here for the first time (Figs 11a View Figure 11 ; 12a-f View Figure 12 ). The holotype, which is the only known specimen of this species, was found to be a small anterior fragment, with structures such as the antennae now missing andsome chaetae broken off. As a result, S. palpopapillata remains a poorly known species, until new material from the type locality becomes available. The holotype (ZMH P-20751) (Fig. 11a View Figure 11 ) is similar to P. modinouae sp. nov. (Fig. 11b, c View Figure 11 ) in the form of the palps and also possesses the elongated lateral body papillae (Fig. 12d View Figure 12 ), which were not reported by Hartmann-Schröder and Rosenfeldt (1992), although the rows of dorsal papillae were not confirmed by us. The main differences observed were the form and length of ventral cirri, which are distinctly longer and slender in S. modinouae sp. nov. (Figs 9b, c View Figure 9 ; 12b, c View Figure 12 ). While both species have unidentate falcigers, their blades in S. palpopapillata are shorter (6-7 µm) and similar in size where observed (Fig. 12e, f View Figure 12 ), but in the new species their lengths are more variable (Fig. 10d-g View Figure 10 ) as already discussed in comparison with P. isabellae . Furthermore, the image provided in the original description ( Hartmann-Schröder and Rosenfeldt 1992: fig. 34) suggests that antennae in S. palpopapillata are large, not small as in the new species or in P. isabellae . Unfortunately, as already mentioned, the antennae have since been lost in the holotype of S. palpopapillata and this character cannot be verified.
The lack of detailed descriptions and reliable drawings/images of the known species from the southern waters, complicate the efforts in describing new species. While we believe that observations provided in this study justify the establishment of a new species from the Falkland Islands material, the known species are clearly in need of revision. However, such an undertaking is beyond the scope of this study.
Etymology.
This species is dedicated to Yvett Modinou, a passionate science communicator, who inspired the fourth author (BS) to join the NHM London.
Distribution.
This species is only known from its type locality, North Falklands Basin, ca. 450 m depth.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.