Pseudonereis formosa Kinberg, 1865

Conde-Vela, Víctor M., 2018, New species of Pseudonereis Kinberg, 1865 (Polychaeta: Nereididae) from the Atlantic Ocean, and a review of paragnath morphology and methodology, Zootaxa 4471 (2), pp. 245-278 : 270-271

Pseudonereis formosa Kinberg, 1865

Pseudonereis formosa Kinberg 1865: 174 .

Pseudonereis gallapagensis Hartman 1948: 68 –69. Bakken 2007: 157 –159, Fig. 7A–F (partim, non Kinberg, 1865).

Type locality. Honolulu , Hawaii, Pacific Ocean.

Diagnosis (after Hartman 1948 and Bakken 2007). Two pair of eyes, rounded. Four pairs of anterior cirri, longest one reaching chaetiger 3–4. Jaws with cutting edge dentate, 5–7 teeth. Maxillary ring: I= 1 cone; II= 3 comb-like rows; III= 4 comb-like rows; IV= 4 comb-like rows. Oral ring: V= 1 cone; VI= 1-1 shield-shaped bars with pointed tips; VII–VIII= one furrow row with P-bars and one ridge row with cones in a single band, rows vertically displaced; furrow and ridge regions with one paragnath each, 18–19 paragnaths in total. Parapodial cirri pattern: dorsal cirri twice as long as notopodial dorsal ligules in anterior chaetigers, 1.5 times longer in middle and posterior chaetigers, becoming shorter in posterior-most chaetigers, basally inserted in anterior-most chaetigers, medially displaced in anterior chaetigers, subdistal in middle and posterior chaetigers, distal in posterior-most chaetigers; ventral cirri shorter than neuropodial ventral ligules and basally inserted throughout body. In posteriormost chaetigers, notopodial dorsal ligule 2.6 times longer than dorsal cirrus, twice as long as wide, 4 times longer than notopodial ventral ligule; notopodial ventral ligule 5 times longer than neuroacicular ligule. Neuroacicular ligules distally bilobed in anterior chaetigers only. Neuropodial heterogomph spinigers in sub-acicular fascicles absent throughout body. Pygidium multi-incised, anal cirri as long as last 4–5 chaetigers.

Remarks. Hartman (1948: 68) examined the types of P. gallapagensis and P. formosa and synonymized them because no differences were found but highlighted that the holotype of P. gallapagensis was in poor condition. Bakken (2007: 157) reexamined both types, including additional material from Chile and Peru; he agreed with Hartman’s conclusion and retained the synonymy, redescribing P. gallapagensis with the type material of both species, but illustrating it with the type of P. formosa . The diagnosis presented here is based on the description by Hartman (1948) and the drawings by Bakken (2007, Fig. 7 ).

P. gallapagensis and P. formosa are quite similar, especially in the large notopodial dorsal cirri with dorsal margins strongly convex in posterior-most chaetigers, but based on the available redescription of P. formosa and the current description of P. gallapagensis , some differences between them can be noted. In P. formosa , notopodial dorsal ligules in middle chaetigers are oblong, laterally flattened, longer than notopodial ventral ligules, whereas in P. gallapagensis they are subconical, subequal than notopodial ventral ligules. Moreover, in P. formosa , notopodial dorsal ligules in posterior-most chaetigers are 4 times longer than notopodial ventral ligules, whereas in P. gallapagensis they are 7–8 times longer. In P. formosa , notopodial ventral ligules in posterior-most chaetigers are twice as long as neuroacicular ligules, whereas in P. gallapagensis they are subequal. Furthermore, P. gallapagensis has neuropodial heterogomph spinigers in sub-acicular fascicles in middle and posterior chaetigers, whereas P. formosa lacks them throughout body. For these discrepancies, P. formosa is herein regarded as a distinct, valid species.

Distribution. Hawaii.

Figures

FIGURE 7. Pseudonereis citrina sp. n. Holotype A–C, F–P (ECOSUR 0194); paratypes D (ECOSUR 0195) and E (ECOSUR 0196). A, anterior end, dorsal view. B, posterior end, dorsal view (insert: close-up of glandular masses in notopodial ligules). C, left jaw, dorsal view. D and E, pharynx areas V and VI. F, chaetiger 2, right parapodium. G, chaetiger 10, right parapodium. H, chaetiger 24, right parapodium. I, chaetiger 38, right parapodium. J, chaetiger 56, right parapodium. K, sub-acicular heterogomph spiniger, chaetiger 56. L, supra-acicular heterogomph falciger, chaetiger 56. M, sub-acicular heterogomph falciger, chaetiger 56. N, sub-acicular heterogomph falciger, chaetiger 38. O, notopodial homogomph spiniger, chaetiger 38. P, sub-acicular heterogomph spiniger, chaetiger 56. Scale bars: A, B, 1 mm; C, 0.3mm; D, E, 0.1 mm; F–J, 0.2 mm; K–N, 10 µm; O, P, 30 µm.