Perinereis damietta, 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 damietta sp. nov.

Fig. 5

Material examined.

Holotype: DUFS 055, Hurghada (northern Red Sea), Grand Aquarium beach, subtidal area, clay bottom, at 27°07'59.2"N, 33°49'51.2"E . Paratypes: 22 specimens (DUFS 027-048) and non-type material 6 specimens (DUFS 049-054) from 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 and from Hurghada , National institute of Oceanography beach, intertidal and upper subtidal area, from muddy and sand bottoms, at 27°17'03.1"N, 33°46'19.8"E ( Egypt) .

Description.

Holotype (DUFS 055) not complete, 94 chaetigers, 62 mm in length, 4.5 mm wide at chaetiger 10. Paratypes with 42-96 chaetigers for 30-115 mm long and 1.5-7 mm wide at chaetiger 10. Epidermis with orange and gold pigmentation on anterior dorsum and ventrum in some preserved samples.

Prostomium with entire anterior margin; relatively large, longer than wide, two pairs of eyes, dark green with black lenses, and two large palps longer than antennae, palpostyles conical. Antennae closely set, as long as ~ 1/3 length of prostomium. Lenses not obvious.

One apodous anterior segment, ~ 1.6 × longer than chaetiger 1. Tentacular cirri with distinct cirrophores, longest tentacular cirri extend back to chaetiger 2 (2-4).

Pharynx with jaws black, 4 (4-5) reddish brown teeth. Paragnaths black with light brown base; those of maxillary ring pointed conical paragnaths. Paragnath counts: area I with 0 (0-2); area II with 2 (1-5) on the left side and 3 (2-5) on the right side; area III with 4 (3-9) in one transverse row; area IV with 14 (10-21) on the left side and 16 (10-20) on the right side; arranged in irregular row of unequal paragnaths. Area V with 0 (0-1); area VI with 24 (24-40) conical paragnaths arranged in one arc; area VII-VIII with 24 (16-32), similar in size, arranged in two rows (Fig. 5A, B ). 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. 5A ).

Anterior notopodia with conical dorsal and median ligules of equal length in anterior body; dorsal ligule slightly longer in mid- and posterior body. DC length 0.8 (0.7-1.0) × length of DNL length anteriorly (chaetigers 10-20); posteriorly, DC length 1.1 (0.9-1.2) × length of DNL (chaetigers 75-90). DC and DNL of mid-body parapodia proportionally similar to those of posterior parapodia (Fig. 5D ).

Dorsal notopodial ligule; triangular with conical tip, slightly longer than notopodial ventral ligule throughout. Ventral notopodial ligule rounded triangular. Dorsal and ventral notopodial ligules marked decreasing in size on posterior chaetigers. Neuropodium with dorsal rounded lobe in anterior chaetigers, with one black acicula, less developed posteriorly. Ventral neuropodial ligule digitiform, similar in length to acicular ligule on anterior chaetigers; slightly longer than acicular ligule in posterior chaetigers. Ventral cirri extending to ~ 1/3 length of ventral neuropodial ligule anteriorly and posteriorly (Fig. 5D-F ).

Notochaetae with homogomph spinigers, long and thin serrated blade throughout. Neurochaetae dorsal fascicle: homogomph spinigers; median thick serrated blade present and heterogomph falcigers present on anterior and posterior chaetigers, blades serrated. Neurochaetae ventral fascicle: heterogomph falcigers with median long and wide blades with a single terminal tooth, in anterior and posterior chaetigers (Fig. 5G-I ). Aciculae black with red-brown base, single in each ramus.

Pygidium with anal cirri cirriform, cirri extending to last 2 (2-4) chaetigers (Fig. 5C ).

Distribution and habitat.

Gulf of Suez, northern Red Sea; intertidal and subtidal, sand and mud, under stones.

Etymology.

The new species is named after the university of the first author, Damietta University, a noun in apposition. Damietta (Egyptian Arabic: Dumyāț (دمياط) is also a port city located on an eastern distributary of the Nile Delta, ~ 15 km from the Mediterranean Sea.

Remarks.

Perinereis damietta sp. nov. is well supported by the highest bootstrap value of 100 (Fig. 2C ) and clearly set apart from the other Perinereis species in the tree. According to the present molecular phylogeny, the sister group to P. damietta is P. vallata , which is also a former variety of P. nuntia ( Wilson and Glasby 1993; Glasby and Hsieh 2006). Not considering identical sequences between specimens within each species, the average genetic distance to its sister group is 42.57% ( ± 6.72%), while the average genetic distance within P. damietta is 1.12% ( ± 0.74%) and hence substantially lower. Hence, there is again a clear gap in the genetic distances.

Herein, P. vallata also includes one specimen (JX966314) assigned to P. brevicirris (Fig. 2C ). This is probably a misidentification given the very strong bootstrap support values of 100 for both the monophyly of P. vallata and the group of P. brevicirris specimens mentioned above (Fig. 2A, C ).

Perinereis damietta is morphologically most similar to P. heterodonta (type locality: Obock, Djibouti, Gulf of Aden). Both species belong to the group of the P. nuntia complex that lack heterogomph spinigers in anterior parapodia, which is unlike P. nuntia . Other key differences between P. damietta / P. heterodonta and P. nuntia are the shorter tentacular cirri and the fewer paragnaths in area V (0-1) (Table 2 ). Perinereis damietta differs from P. heterodonta most notably in having 24-40 pyramidal paragnaths in area VI (vs. 10-16 in P. heterodonta ). In this regard, it has the highest number of area VI paragnaths of any species in the P. nuntia species complex, exceeding the next highest (12-16 bars) found in P. vallata ( Wilson and Glasby 1993).

Another species originally described from Djibouti, Perinereis djiboutiensis , is unfortunately poorly known, especially in respect to the presence or absence of heterogomph spinigers in anterior parapodia and numbers of paragnaths in areas III and VII-VIII (Table 2 ). Although it resembles the new species in having one, or no, paragnaths in area V, it may be differentiated from the new species in having only six or seven short bars (may also include cone-shaped paragnaths) in area VI, which is the lowest of all species of the Perinereis nuntia species group in the region (Table 2 ), and in this regard it is closer to material described as Perinereis nuntia from the Red Sea by Wilson and Glasby (1993).

A novel character introduced by Villalobos-Guerrero (2019), the size of the gap between areas VI and VII-VIII, may also set this new species (and others in this study) apart from other members of the P. nuntia complex. The gap in all three species described here is about 'as wide as palpophore’, which is similar to P. nuntia according to Villalobos-Guerrero (2019), but differs from the Southern Ocean species P. latipalpa (Schmarda, 1861) from South Africa and P. vallata from Chile in which the gap is only as wide as the palpostyle ( Wilson and Glasby 1993; Villalobos-Guerrero 2019).

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 5. Perinereis damietta 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, posterior view, chaetiger 9 E right parapodium, posterior view, chaetiger 41 F right parapodium, anterior view, chaetiger 56 G chaetal bundle of a right parapodium, homogomph spiniger & heterogomph falciger chaetiger 56 H neuropodial chaetal bundle of a right parapodium, heterogomph falciger, chaetiger 56 I heterogomph falciger, chaetiger 67.