Pseudonereis ferox ( Hansen, 1882 )

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 : 269-270

Pseudonereis ferox ( Hansen, 1882)

Nereis ferox Hansen 1882: 14 , Pl. 4, Figs. 34–39. Horst 1889: 174 –178, Pl. 7, Figs. 6–8 . Augener 1934: 133.

Nereis coerulea Hansen 1882: 11 , Pl. 3, Fig. 31, Pl. 4, Figs. 1–3 .

Nereis microphthalma Hansen 1882: 13 , Pl. 4, Figs. 25–28.

Nereis obscura Hansen 1882: 13 , Pl. 4, Figs. 18–24.

Pseudonereis variegata Bakken 2007: 168 –171, Figs. 14A–C, 15A–H (non Grube & Kröyer in Grube, 1858).

Type locality. Rio de Janeiro, Brazil, Atlantic Ocean.

Diagnosis (after Bakken 2007). Two pairs of eyes, anterior pair semilunar, posterior one rounded. Four pairs of anterior cirri, longest one reaching chaetiger 5. Jaws with cutting edge dentate, 4–5 teeth. Maxillary ring: I= 1–2 cones; II= 3 comb-like rows; III= 4 comb-like rows; IV= 4–5 comb-like rows. Oral ring: V= 1 cone; VI= 1-1 crescent-shaped bars; 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, 18–21 paragnaths in total. Parapodial cirri pattern: dorsal cirri as long as notopodial dorsal ligules in anterior and middle chaetigers, becoming shorter in posterior and 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 then neuropodial ventral ligules and basally inserted throughout body. In posterior-most chaetigers, notopodial dorsal ligule 2.6 times longer than dorsal cirrus, twice as long as wide, 3 times longer than notopodial ventral ligule; notopodial ventral ligule twice as long as neuroacicular ligule. Neuroacicular ligules distally bilobed throughout body. Neuropodial heterogomph spinigers in sub-acicular fascicles present from about chaetiger 40. Pygidium multi-incised, anal cirri as long as last five chaetigers.

Remarks. Bakken (2007), following Ehlers (1901) and Augener (1934), redescribed P. variegata with the syntypes of Nereis ferox from Rio de Janeiro, Brazil, because the type material of Nereis (Nereilepas) variegata Grube & Kröyer in Grube, 1858 was not available. The type of N. variegata was also unavailable for this study, but some topotype specimens were located in the USNM. Some publications characterizing the species from localities in South American Pacific coasts were also taken into account.

Horst (1889) examined Hansen’s (1882) types of Nereis ferox , N. coerulea , N. microphthalma and N. obscura , all species from Brazil, and synonymized the last three species with N. ferox because he did not find major differences, and placed N. ferox in the Perinereis group featured by having a single paragnath in area I. Ehlers (1901) examined the holotype of P. variegata and synonymized Paranereis elegans Kinberg, 1865 by comparing the original description, a decision supported by Hartman (1948: 69–70) after the examination of type material of P. elegans ; Bakken (2007) found the type of P. elegans in very poor condition. Also, Ehlers (1901: 117) agreed with Horst (1889) about the synonymy of N. coerulea , N. ferox , N. microphthalma and N. obscura . Ehlers (1901: 114) noticed the difference in attachment of dorsal cirrus in specimens he examined, where some had distal dorsal cirri and very vascularized notopodial dorsal ligules in posterior chaetigers, whereas other ones, including the holotype of P. variegata , had subdistal dorsal cirri and less vascularized notopodial dorsal ligules; also, specimens with distal dorsal cirri ( Ehlers 1901, Pl. 14, Figs. 11 –13) had dorsal cirri much longer than in P. variegata and P. gallapagensis as herein described. This evidence indicates that Ehler’s specimens belonged to more than one species.

Augener (1934) examined Hansen’s type material, highlighting two important features in all descriptions: the dorsal cirri distally inserted, and one large paragnath in the areas VI in N. coerulea , N. ferox , and N. obscura ; based on these features, Augener (1934) agreed with Ehlers (1901) about the synonymy of Hansen’s species with P. variegata . Given that most of Hansen’s material is now lost ( Bakken 2007: 171), here the synonymy of N. coerulea , N. microphthalma and N. obscura proposed by Augener (1934) is retained under the name P. ferox , but the synonymy with P. variegata is rejected based on the current descriptions. Augener (1934) also examined the holotype of Phyllonereis benedeni Hansen, 1882 , finding it fragmented and deprived of pharynx, and tentatively he assigned it to P. variegata ; the illustrated parapodia ( Augener 1934, Fig. 25) resembles that of P. ferox , but since the pharyngeal ornamentation is unknown, it is preferable to maintain P. benedeni and P. ferox as independent species until a further study clarifies its status.

Based on the current descriptions, there are several differences between P. ferox and P. variegata , the most conspicuous of which are: 1) P. ferox has one band with 18–21 paragnaths, whereas P. variegata has two bands with 39–41 paragnaths; and 2) in P. ferox , dorsal cirri are distally inserted in posterior chaetigers, whereas in P. variegata they are subdistally inserted. Moreover, in P. ferox , dorsal cirri are subequal in anterior and middle chaetigers, whereas in P. variegata they are progressively larger toward the middle of the body. In P. ferox , notopodial dorsal ligules are very expanded and they are 2–3 times longer than dorsal cirri, whereas in P. variegata they are subequal and notopodial dorsal ligules are not much expanded. Also, in P. ferox , neuroacicular ligules are distally bilobed throughout body, whereas in P. variegata they are conspicuous in anterior chaetigers only. The pigmentation pattern could be distinct but there is no information about for P. ferox , and pigments are faded out in the type specimens ( Bakken 2007). Based on the current evidences, here P. ferox is regarded as a valid species, distinct from P. variegata .

P. ferox closely resembles P. gallapagensis , but the following differences can be noted. P. ferox has crescentshaped bars in the areas VI, whereas P. gallapagensis has shield-shaped bars. Also, in P. ferox , notopodial dorsal ligules are 3 times longer than notopodial ventral ligules in posterior chaetigers, whereas in P. gallapagensis they are about 7–8 times longer. Also, in P. ferox , notopodial ventral ligules are twice as long as neuroacicular ligules in middle and posterior chaetigers, whereas in P. gallapagensis they are subequal throughout body.

Distribution. Brazil.

Figures

FIGURE 1. Proposal of division of pharyngeal midventral area. A, Kinberg’s drawings of ventral pharynx of Perinereis novaehollandiae (9C.) and Mastigonereis spinosa (10C.), showing the area VII and VIII as originally was intended; gray areas are intended to highlight midventral area in white. B, midventral area, composed of the areas III, VII and four subareas of area VIII; areas VII and VIII subdivided in furrow (lowercase letters) and ridge (uppercase letters) regions from both left (suffix l) and right (suffix r). A redrawn from Kinberg (1910).

FIGURE 2. The midventral pharynx area in some nereidid genera. A, midventral area in Alitta succinea (ECOSUR P2729). B, midventral area in Pseudonereis gallapagensis (USNM 24266). C, midventral area in Nereis garwoodi (ECOSUR P2831). D, midventral area in Perinereis floridana (ECOSUR P1100). E, midventral area in Hediste cf. diversicolor (USNM 58131). F, midventral area in Kainonereis polaris (USNM 55514). G, midventral area in Platynereis magalhaensis (ECOSUR P2935). A– B and E–F show pharynges fully everted; C–D show pharynges partially everted; G shows a pharynx dorsally dissected. The midventral area in all drawings is highlighted in white.

FIGURE 3. Transversal distribution of paragnaths in the furrow and ridge regions. A, Alitta succinea (ECOSUR P2729), five rows in two bands. B, distances among rows in region A of A. succinea, showing the gap between the bands. C, Nereis garwoodi (ECOSUR P2831), two rows in two bands. D, distances among rows in region A of N. garwoodi, showing the gap between the bands. E, Hediste cf. diversicolor (USNM 58131), three rows in two bands. F, distances among rows in region B r of H. cf. diversicolor, showing the gap between the bands. G, Perinereis floridana (ECOSUR P1100), three rows in two bands. H, distances among rows in region A of P. floridana, showing the gap between the bands. I, Pseudonereis gallapagensis (USNM 24266), two rows and one band. J. Platynereis magalhaensis (ECOSUR P2935), two rows and one band.

FIGURE 6. Pseudonereis brunnea sp. n. Holotype A–H (ECOSUR 0191); paratypes I–O (ECOSUR 0192). A, anterior end, dorsal view. B, posterior end, dorsal view. C, chaetiger 2, right parapodium. D, chaetiger 10, right parapodium. E, Chaetiger 26, right parapodium. F, chaetiger 46, right parapodium. G, chaetiger 65, right parapodium. H, close up of anterior end. I, maxillary ring, frontal view. J, oral ring, frontal view. K, supra-acicular heterogomph falciger, chaetiger 55. L, sub-acicular heterogomph falciger, chaetiger 55. M, sub-acicular heterogomph spiniger, chaetiger 55. N, notopodial homogomph spiniger, chaetiger 55. O, sub-acicular heterogomph spiniger, chaetiger 55. Black triangles= points used for length measurement. Scale bars: A, B, 1 mm; C–G, 0.2 mm; H–J, 0.5 mm; K–M, 10 µm; N, O, 30 µm.

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.

FIGURE 8. Pseudonereis fauveli sp. n. Holotype A–M (USNM 1494007). A, anterior end, dorsal view. B, posterior end, dorsal view. C, chaetiger 2, right parapodium. D, chaetiger 13, right parapodium. E, chaetiger 32, right parapodium. F, chaetiger 50, right parapodium. G, chaetiger 67, right parapodium. H, right jaw in lateral (left) and dorsal (right) view. I, supraacicular homogomph spiniger, chaetiger 13. J, supra-acicular heterogomph falciger, chaetiger 13. K, sub-acicular heterogomph falciger, chaetiger 13. L, supra-acicular heterogomph falciger, chaetiger 67. M, sub-acicular heterogomph falciger, chaetiger 67. Scale bars: A, 1 mm; B–H, 0.2 mm; I–M, 10 µm.

FIGURE 11. Paragnaths arrangement in Perinereis cariboea de León-González & Solís-Weiss, 1998. A, dissected pharynx of the holotype (USNM 180694). B, pharynx of non-type specimen (ECOSUR 2934), ventral view. C, pharynx partially everted of non-type specimen (ECOSUR 2933), ventral view; arrows point to the paragnaths of the second band. Scale bars: A, 0.1 mm; B, C, 0.5 mm.