Pseudonereis variegata (Grube & Kröyer in Grube, 1858 )

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 : 266-269

Pseudonereis variegata (Grube & Kröyer in Grube, 1858)

Figure 10A–J

Nereis (Nereilepas) variegata Grube 1858: 164 –165.

Nereis variegata Ehlers 1901: 112 –118, Pl. 14, Figs. 1–9 (partim).

Pseudonereis variegata Monro 1933: 45 (combination only). Hartmann-Schröder 1962b: 434 –435 (partim). Rozbaczylo & Bolados 1980: 221 –223, Fig. 6a–d .

Type locality. Valparaiso, Chile, Pacific Ocean.

Material examined. Eastern Pacific Ocean, Chile. USNM 176578 (1), R/V Eltanin, St. 300, Viña del Mar, Valparaiso, 22 September 1966, Coll. Smithsonian Oceanographic Sorting Center ( SOSC). USNM 176579 (2), R/ V Eltanin, St. 300, Viña del Mar, Valparaiso, 22 September 1966, Coll. Smithsonian Oceanographic Sorting Center ( SOSC).

Description. Largest specimen (USNM 176579) incomplete, 38 mm long, 2 mm wide, 89 chaetigers, pigments present and pharynx everted. Another one (USNM 176578) complete, 19 mm long, 1.8 mm wide, 64 chaetigers, pigments faded and pharynx not everted ( Fig. 10A ). Largest specimen variegated: brown pigment in prostomium, palps and achaetous ring; at the dorsum, three brown rectangles, two lateral and one central, forming longitudinal rows, lateral ones larger than central ones in most-anterior chaetigers, lateral ones becoming shorter than central ones toward posterior end and fading out since middle of body, only central rectangle remaining and becoming shorter toward posterior end; lateral fingerprint-like pattern present throughout body ( Fig. 10C ).

Prostomium as long as wide; antennae cirriform to digitiform, half as long as prostomium, not passing the palps; eyes black or reddish, in trapezoidal arrangement ( Fig. 10A, C ). Achaetous ring twice as long as first chaetiger; four pairs of anterior cirri, cirrophores conspicuous, longest one reaching chaetiger 5 ( Fig. 10A, C ).

Pharynx everted; jaws dark brown, cutting edge dentate. Maxillary ring: I= 1 cone; II= 4-4 comb-like rows in triangle; III= 4 comb-like rows in triangle; IV= 5-5 comb-like rows and additional cones, merged cones and P-bars, in sigmoid ( Fig. 10D–E ). Oral ring: V= 1 cone; VI= 1-1 crescent-shaped bars; VII–VIII= anterior band with one furrow row with 12 P-bars and one ridge row with 11 cones; posterior band with one furrow row with 8 P-bars and one ridge row with 12 cones, rows vertically displaced; furrow and ridge regions with one paragnath each ( Fig. 10D–E ).

Parapodial cirri pattern: Dorsal cirri longer than notopodial dorsal ligules in anterior region, becoming shorter toward posterior end; basally inserted to dorsal ligules in most anterior segments, displaced medially in medial segments, subdistal in posterior segments and distal in posterior ones, extending beyond notopodial dorsal ligules throughout body. Ventral cirri longer than neuropodial ventral ligules in anterior-most chaetigers; subequal and basally inserted to neuropodial ventral ligules throughout body.

First two chaetigers with neuroaciculae only, remaining ones with both noto- and neuroaciculae. In first two chaetigers ( Fig. 10F ), dorsal cirrus basal, 1.2 times longer than dorsal ligule. dorsal ligule digitiform, as long as neuroacicular ligule. Neuroacicular ligule subconical, twice as long as neuropodial ventral ligule, distally bilobed, superior lobe smaller than inferior one; postchaetal lobe rounded, half as long as neuroacicular ligule; neuropodial ventral ligule digitiform. Ventral cirrus basal, twice as long as neuropodial ventral ligule.

In anterior chaetigers ( Fig. 10G ), dorsal cirrus medial, 1.2 times longer than notopodial dorsal ligule. Notopodial dorsal ligule subconical, blunt, subequal than notopodial ventral ligule; notopodial ventral ligule subconical, blunt. Neuroacicular ligule subconical, twice as long as neuropodial ventral ligule, distally bilobed, superior one much smaller than inferior one, almost inconspicuous; postchaetal lobe rounded, half as long as neuroacicular ligule; neuropodial ventral ligule digitiform. Ventral cirrus basal, subequal than neuropodial ventral ligule.

In middle chaetigers ( Fig. 10H ), dorsal cirrus medial, twice as long as notopodial dorsal ligules. Notopodial dorsal ligule subconical, blunt, subequal than notopodial ventral ligule; notopodial ventral ligule digitiform, subequal than neuroacicular ligule. Neuroacicular ligule subconical, blunt, 2–3 times longer than neuropodial ventral ligule; neuropodial ventral ligule digitiform. Ventral cirrus basal, as long as neuropodial ventral ligule.

In posterior chaetigers ( Fig. 10I ), dorsal cirrus subdistal, as long as notopodial dorsal ligule. Notopodial dorsal ligule pennant-like, 1.2 times longer than wide, 3–4 times longer than notopodial ventral ligule; notopodial ventral ligule digitiform, twice as long as neuroacicular ligule. Neuroacicular ligule subconical, 2–3 times longer than neuropodial ventral ligule; neuropodial ventral ligule digitiform. Ventral cirrus basal, as long as neuropodial ventral ligule.

Notochaetae homogomph spinigers. Neurochaetae homogomph spinigers and heterogomph falcigers in supraacicular fascicles, heterogomph spinigers and falcigers in sub-acicular fascicles.

Neuropodial falcigers falcate, pectinate, narrow teeth, half or two third of inner edge edentate, distal tip stout ( Fig. 10J ).

Pygidium, crenulated; anal cirri cirriform, as long as last segment ( Fig. 10B ).

Remarks. Grube (1858) included 11 new Nereis species and placed them into the subgenera Nereis s.s. Örsted, Nereilepas de Blainville , and Heteronereis Örsted , and this scheme was confirmed in the index to all species ( Grube 1859: 119). Consequently, here the combination Nereis (Nereilepas) variegata Grube & Kröyer in Grube, 1858 is used, and not as originally placed in genus Nereilepas as suggested by other authors (e.g. Hartman 1959; Salazar-Vallejo & Eibye-Jacobsen 2012). Grube (1858) described the pigmentation as anteriorly purplish brown or puce, often with three rows in the dorsum, or rarely puce spots in mosaic, the specimens examined match with such pigmentation pattern. Other relevant features included are: 1) longest anterior cirri reaching chaetigers 2–3; 2) anterior ring of pharynx (maxillary ring) with three groups of paragnaths (areas III and IV) ventrally, and two groups of paragnaths dorsally, one of them with one or two denticles (areas II and I); 3) posterior ring of pharynx (oral ring) with duplicate bands (areas VII–VIII) ventrally, and three juxtaposed denticles (areas V and VI); and 4) notopodial dorsal cirri ovate in middle chaetigers, gradually becoming sublanceolate (perhaps because the small distal lobe).

Several species have been synonymized with P. variegata ( Read 2018) , especially species from Atlantic Ocean, but in the redescription of P. variegata by Bakken (2007) only the species Nereis ferox Hansen, 1882 , was regarded as synonym. Further comments of these synonyms can be found in Remarks sections of P. fauveli sp. n. and P. ferox . Rozbaczylo & Bolados (1980) made a useful description of P. variegata with specimens collected near the type locality; their specimens kept the pigment, and their description fully agrees with the current one, even in the presence “…at each side of each chaetiger with drawings resembling concentric circles…” (p. 221) ( Fig. 8C , insert). The kind of attachment of dorsal cirri (distal or subdistal) and the number of rows in the areas VII–VIII are key differences when comparing P. variegata with P. gallapagensis (e.g. Fauchald & Reimer 1975: 85; Hartmann- Schröder 1962b: 435) (see Remarks section of P. ferox below).

There are only two known Pseudonereis species with similar arrangement and number of paragnaths in the areas VII–VIII: P. cortezi (Kudenov, 1979) and P. pseudonoodti ( Fauchald, 1977a) . The main differences among them is that P. variegata has 1 cone in the area V, about 42 paragnaths in the areas VII–VII, and dorsal cirri subdistally inserted in posterior-most chaetigers, whereas the P. cortezi and P. pseudonoodti have 3 or more paragnaths in the area I, more than 60 paragnaths in the areas VII–VIII, and dorsal cirri distally inserted in posterior-most chaetigers.

Distribution. Chile.

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 4. Longitudinal distribution of paragnaths in the furrow and ridge regions. A, Neanthes cf. acuminata (ECOSUR P2936), showing the longitudinal alignment of paragnaths. B, same, diagram of the distribution of paragnaths in a pharynx fully everted. C, Nereis pelagica (ECOSUR P2840), showing the irregular distribution of paragnaths. D, same, diagram showing the paragnaths longitudinally aligned, paragnaths of the same color belong to the same longitudinal row. E, same, diagram showing longitudinal rows obtained when connecting the dots (paragnaths) of the same row.

FIGURE 5. Classification of some rectangular-base paragnaths. A, shield-shaped bars. B, crescent-shaped bars. C and D, pointed bars (P-bars). Drawings show the tip (dark brown) and base (light brown) of paragnaths, in both anterior and superior views; each drawing is accompanied with a picture of the same paragnath and at the same view. Green arrowheads point toward the anterior end of the body, showing the relative position of the paragnaths in relation to the pharynx axis. Blue vertical triangles point to the distal tip of the paragnaths; red triangles point the midpoint of the bases, and white dotted lines represent the bases’ altitude lines. A, D, Pseudonereis brunnea sp. n. (ECOSUR P2926); B, Perinereis floridana (ECOSUR P1100); C, Nereis garwoodi (ECOSUR P2831).

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 9. Pseudonereis gallapagensis Kinberg, 1865. Non-types A–B, E–K (USNM 24265), non-type C–D (USNM 24266). A, anterior end, dorsal view. B, posterior end, dorsal view. C, pharynx, dorsal view. D, same, ventral view. E, subacicular heterogomph falcigers, chaetiger 12. F, supra-acicular heterogomph falciger, chaetiger 40. G, sub-acicular heterogomph falciger, chaetiger 40. H, chaetiger 2, right parapodium. I, chaetiger 12, right parapodium. J, chaetiger 30, right parapodium. K, chaetiger 73, right parapodium. Scale bars: A–D, 1 mm; E–G, 10 µm; H–K, 0.2 mm.

FIGURE 10. Pseudonereis variegata (Grube & Kröyer in Grube, 1858). Topotype A–B, I–J (USNM 176578); topotype C– H (USNM 176579). A, anterior end, dorsal view. B, posterior end, dorsal view. C, anterior end, dorsal view (insert: close-up of chaetigers 20–22). D, pharynx, dorsal view. E, same, ventral view. F, chaetiger 1, right parapodium. G, chaetiger 13, right parapodium. H, chaetiger 41, right parapodium. I, chaetiger 56, right parapodium. J, sub-acicular heterogomph falciger, chaetiger 56. Scale bars: A–C, 1 mm; D, E, 0.5 mm; F–I, 0.1 mm; J, 10 µm.