Perinereis fayedensis, Elgetany & Struck & Glasby, 2022

Elgetany, Asmaa Haris, Struck, Torsten H. & Glasby, Christopher J., 2022, Three new species of the genus Perinereis (Annelida, Nereididae) from Egyptian coasts, ZooKeys 1132, pp. 163-188 : 163

Perinereis fayedensis sp. nov.

Fig. 4

Material examined.

Holotype: DUFS 0123 Al-Adabiya , west of Port Taofik, Gulf of Suez (Red Sea), intertidal, under coarse sands, at 29°56'06.0"N, 32°28'36.6"E . Paratypes (DUFS 120-122, 124-128): 8 specimens from El-Qantara , Suez Canal , intertidal, muddy sand bottom, at 30°50'31.5"N, 32°18'54.8"E, Fayed , western shore of Great Bitter Lake, intertidal, silty mud bottom, at 30°20'18.0"N, 32°18'14.9"E, Al-Adabiya (same collection details as holotype) .

Description.

Holotype (DUFS 0123) not complete, 49 chaetigers, 35 mm in length, 3 mm wide at chaetiger 10. Paratypes with 37-88 chaetigers, 30-70 mm long, 1.5-4.5 mm wide at chaetiger 10. Epidermis whitish cream with a longitudinal beige pigmentation stripe on ventral side of posterior chaetigers in some preserved.

Prostomium with entire anterior margin; wide as long. Antennae closely set, as long as ~ 1/3 length of prostomium. Eyes black, anterior pair set slightly further apart than posterior pair; lenses not obvious.

Apodous segment ~ 1.5 × longer than chaetiger 1. Posterodorsal tentacular cirri with distinct cirrophores, extend back to chaetiger 7 (6-8).

Pharynx with jaws translucent red-brown, with 8 (7-8) teeth. Maxillary ring of pharynx with paragnaths, arranged in discrete areas, areas II-IV arranged in regular comb-like rows. Area I with 2 (1-2) conical paragnaths in vertical arrangement; area II with 9 (7-10) in left and 9 (7-10) in right conical paragnaths, three or four rows in a triangular patch; area III with 2 (2-5) conical paragnaths in vertical arrangement; area IV with 13 (12-15) in left, 14 (12-15) in right, conical paragnaths without bars; area V with 4 (1-3) conical paragnaths; area VI with 17 (14-17), shield-shaped bars with pointed tip present, cones paragnaths absent; area VII-VIII with 38 (28-40) conical paragnaths with small p-bars interspersed arranged in a single band of 3-5 rows (Fig. 4A, B ; Table 2 ). Paragnath-free region between areas VI and VII-VIII broad, ca. as wide as palpophore; paragnaths of VII-VIII not visible in dorsal view (Fig. 4A ).

Notopodia with conical dorsal and median ligules of equal length throughout. Superior lobes absent. DC length 1.2 (0.9-1.2) × length of DNL length anteriorly (chaetigers 10-20); posteriorly, DC length 1.2 (1.1-1.2) × length of DNL length (chaetigers 75-90). DC and DNL of mid-body parapodia proportionally similar to those of posterior parapodia (Fig. 4D-F ).

Neuropodia with inferior and postchaetal lobes, ventral ligule and ventral cirri. Neuropodial postchaetal lobe lowly rounded, not projecting beyond end of acicular ligule. Ventral neuropodial ligule subconical, ca. as long as median ligule throughout. Ventral cirri extending laterally to halfway to tip of ventral neuropodial ligule in anterior and midbody, extending to ~ 1/3 length of ventral neuropodial ligule posteriorly (Fig. 4D-F ).

Aciculae black, single in each ramus (Fig. 4G ). Notochaeta with homogomph spinigers throughout, spinigers of long blades; teeth short. Neurochaetae with homogomph spinigers and heterogomph falcigers in the supra and sub-acicular fascicle (Fig. 4G-I ). Acicula black, single in each ramus.

Pygidium with anal cirri fine, tapering, extending to last 7 (6-8) chaetigers, 50 (45-55) mm long (Fig. 4C ).

Remarks.

The molecular data place the new species, P. fayedensis , clearly apart from all other species and as sister to P. suezensis (Fig. 2A ). The monophyly is well supported by a bootstrap value of 99. Not considering identical sequences between specimens within each species, the average genetic distance to its sister-taxon, P. suezensis , is 6.65% ( ± 0.60%), while the average genetic distance within P. fayedensis is substantially lower with a value of 0.01% ( ± 0.00%). Hence, there is again a clear gap in the genetic distances.

Morphologically, P. fayedensis is intermediate between P. nuntia and P. heterodonta described from Obock, Djibouti, Gulf of Aden. It differs from the former most notably in the number of paragnaths in area III (2-5 vs. ~ 15 in P. nuntia ) and area VI (14-17 vs. 8-12 in P. nuntia ), and the relative length of the DC (1.1-1.2 × DNL in the new species vs. 3-5 × DNL in P. nuntia ; Table 2 ). Perinereis fayedensis can be distinguished from P. heterodonta by having fewer paragnaths in area III (2-5 in one row vs. a cluster of 6-7 in P. heterodonta ) and more paragnaths in area VII-VIII (28-40 vs. 18 in P. heterodonta ) (see Table 2 ).

Distribution and habitat.

Gulf of Suez, Suez Canal including Great Bitter Lake; intertidal sand and mud, under stones.

Etymology.

The new species is named after the Egyptian city of Fayed on the western shore of Great Bitter Lake approximately halfway along the Suez Canal.

Figures

Figure 2. ML tree (logL = - 11297.8710) of the Perinereis species in this analysis shown in three parts (A, B, C). The points, where we cut the branches, are indicated by letters. The new species P. suezensis sp. nov., P. fayedensis sp. nov., and P. damietta sp. nov. are highlighted by boxes and in bold. Perineris nuntia is also highlighted in bold. Bootstrap values equal to and more than 95 indicating strong support are given at the branches. The three relevant bootstrap values are highlighted in bold. The scale bar shows substitutions / position.

Figure 4. Perinereis fayedensis sp. nov. All pictures are from the holotype if not stated otherwise A anterior end, maxillary apparatus, dorsal view B anterior end, maxillary apparatus, ventral view C posterior end, ventral view D right parapodium, anterior view, chaetiger 16 E right parapodium, posterior view, chaetiger 32 F right parapodium, posterior view, chaetiger 67 G chaetal bundle of a right parapodium, homogomph spiniger and heterogomph falcigers, chaetiger 17 H neuropodial chaetal bundle of a right parapodium, homogomph spiniger & heterogomph falciger, chaetiger 33 I heterogomph falciger, chaetiger 33.