Laeonereis brunnea Hartmann-Schröder, 1959

Conde-Vela, Víctor M., 2021, Revision of Laeonereis Hartman, 1945 (Annelida: Phyllodocida: Gymnonereidinae), with a review of shaft morphology in nereidids, Journal of Natural History 55 (7 - 8), pp. 381-455 : 406-410

Laeonereis brunnea Hartmann-Schröder, 1959

( Figures 5 (g), 6, 11(a–f), Figure 12 (a–j))

Laeonereis brunnea Hartmann-Schröder 1959: 135–138 , figs 92–99. Dean 2001: 43–44, figs 10–13.

Laeonereis culveri Pettibone 1971: 15 (partim).

Type material

Western Tropical Pacific, El Salvador. Paratypes USNM 43404 (3), Jaltepeque estuary, El Salvador, Coll . G . Hartmann-Schröder.

Additional material

Western Tropical Pacific, El Salvador. MCZ 84795 (1), Estero Jaltepeque , between Rio Jiboa and Rio Lempa (13.316667°N, 88.916667°W), December 1990 or July 1991, Coll . O .A. Molina-Lara.

Costa Rica. MCZ 145936 (1), Bahia Chatham , Cocos Island (5.551333°N, 87.041056° W), 12 October 2007, Coll . H .K. Dean . MCZ 34777 (1), Golfito , Golfo Dulce (8.633333°N, 83.166667°W), intertidal, September 1986, Coll . J .A. Vargas . MCZ 34779 (1), Golfo Dulce (8.633333°N, 83.166667°W), in sediments around roots of Rhizophora mangle, 1996 , Coll . H . Butner . MCZ 34769 (1), off boat ramp, N side of Punta Morales , Gulf of Nicoya (10°N, 84.966667°W), in upper intertidal mud, July 1996, Coll . H .K. Dean.

Type locality

Isla Perico, Gulf of Fonseca, El Salvador.

Description

Three paratypes (USNM 43404) ( Figure 11 (a)), largest paratype incomplete, 10.5 mm long, 0.5 mm wide at chaetiger 10, 38 chaetigers; second one incomplete, previously dissected, 9 mm long, 0.5 mm wide at chaetiger 10, 40 chaetigers; smaller paratype complete, 8 mm long, 0.4 mm wide at chaetiger 10, 39 chaetigers. Non-type specimen (MCZ 34777) complete ( Figure 11 (d)), 5.5 mm long, 0.6 mm wide at chaetiger 10, 50 chaetigers. Specimens brownish, body pigmentation absent, glands pigmented, more conspicuous in anterior chaetigers.

Prostomium hexagonal, wider than long, anterior margin shallowly cleft, dorsal groove wide and reaching the anterior pair of eyes ( Figure 11 (b,c,e)); antennae subconical, shorter than dorsal groove ( Figure 11 (c)); eyes reddish, rounded, the two pairs subequal ( Figure 11 (b,c,e)). Achaetous ring as long as first chaetiger ( Figure 11 (b,c,e)); four pairs of anterior cirri, cirrophores conspicuous, longest pair of cirri reaching chaetiger 3 ( Figure 11 (c)).

Pharynx dissected. Jaws brownish, 17 teeth, cutting edge completely dentate ( Figure 5 (g)). Maxillary ring: tuft of verticillate rod-like papillae almost inconspicuous, only visible after staining, present in areas I–IV. Oral ring: small papillae in areas VI; papillae inconspicuous in areas VII–VIII.

Pattern of pedal glands ( Figure 6 ). UpG subconical and shorter than MeG in anterior chaetigers, splitting into two or three smaller glands towards middle chaetigers. LoG elliptical and subequal to UpG in anterior chaetigers, becoming narrower in middle chaetigers. MeG ovoid and subequal to PoG in anterior chaetigers, becoming shorter than in middle chaetigers. PoG becoming larger towards middle chaetigers.

First two chaetigers with neuroaciculae only; remaining ones with both noto- and neuroaciculae. In first two chaetigers ( Figure 12 (a)), dorsal cirri digitiform. Dorsal ligules subconical, 1.2 times longer than wide, 4–5 times longer than dorsal cirri, as long as neuropodial postchaetal lobes; neuroacicular ligules digitiform, as long as wide; postchaetal lobes subconical, blunt, twice as long as wide, twice as long as neuroacicular ligules, 1.2 times longer than neuropodial ventral ligules; neuropodial ventral ligules subconical, blunt, 2.5 times wider than long, 2.5 times longer than ventral cirri. Ventral cirri subconical.

In anterior chaetigers ( Figure 12 (b,c)), dorsal cirri linguiform. Notopodial dorsal ligules slightly lanceolate to subconical, 1.6 times wider than long, 6–7 times longer than dorsal cirri, 4 times longer than prechaetal lobes, 1.4 times longer than notopodial ventral ligules; prechaetal lobes digitiform, 1.6 times wider than long; notopodial ventral ligules subconical, blunt, 1.3 times longer than wide, 3.5 times longer than prechaetal lobes, as long as neuropodial postchaetal lobes. Neuropodial postchaetal lobes subconical, blunt, as long as wide, as long as neuroacicular ligules; neuroacicular ligules subconical, as long as wide, 1.6–2.0 times longer than neuropodial ventral ligules; neuropodial ventral ligules subconical, blunt, 3.2 times wider than long, 2 times longer than ventral cirri. Ventral cirri cirriform.

In middle chaetigers ( Figure 12 (d)), dorsal cirri digitiform. Notopodial dorsal ligules subconical, 2.0–2.5 wider than long, 4 times longer than dorsal cirri, 5–6 times longer than prechaetal lobes, 2 times longer than notopodial ventral ligules; prechaetal lobes rounded, 2 times wider than long, becoming gradually shorter and disappearing towards posterior end; notopodial ventral ligules subconical, 1.3 times longer than wide, 6 times longer than prechaetal lobes. Neuroacicular ligules subconical, 2 times wider than long, 4 times longer than neuropodial ventral ligules; postchaetal lobes absent; neuropodial ventral ligules subconical, 5.5 times wider than long, 3.5 times longer than ventral cirri; ventral cirri digitiform.

In posterior chaetigers ( Figure 12 (e)), dorsal cirri digitiform. Notopodial dorsal ligules subconical, 1.4 times wider than long, 2.4 times longer than dorsal cirri, 1.3 times longer than notopodial ventral ligules; prechaetal lobes absent; notopodial ventral ligules subconical, 1.3 times longer than wide, as long as neuroacicular ligules. Neuroacicular ligules subconical, 1.4 times longer than wide, 7 times longer than neuropodial ventral ligules; postchaetal lobes absent; neuropodial ventral ligules subconical, 3.4 times wider than long, 1.3 times longer than ventral cirri. Ventral cirri digitiform.

In posteriormost chaetigers ( Figure 12f ), dorsal cirri lanceolate. Notopodial dorsal ligules absent, appearing towards anterior end; notopodial ventral ligules subconical, as long as wide, twice as long as dorsal cirri. Neuroacicular ligules subconical, 1.5 times longer than wide, twice as long as notopodial ventral ligules, 6 times longer than neuropodial ventral ligules; neuropodial ventral ligules subconical, 5–6 times wider than long, 4 times longer than ventral cirri.

Notochaetae homogomph spinigers. Neurochaetae homogomph spinigers and homogomph falcigers in both supra- and sub-acicular fascicles; supra- and sub-acicular homogomph falcigers appearing from about chaetiger 20.

Supra-acicular homogomph falcigers ( Figure 12 (g)) with serrate blades, sharp teeth, blades 11–12 times longer than wide, becoming slightly shorter than posterior chaetigers, distal tooth stout. Sub-acicular homogomph falcigers ( Figure 12 (h–j)) with pectinate blades, minute teeth, blades 10–11 longer than wide, becoming slightly shorter than posterior chaetigers, distal tooth stout.

Pygidium funnel-shaped ( Figure 11 (a,f)); anal cirri 3 times longer than width of pygidium ( Figure 11 (a,f)).

Remarks

The current description agrees well with the original description by Hartmann-Schröder (1959). The original pigmentation pattern is unique among Laeonereis species , although in the specimens the pigments are faded. Hartmann-Schröder (1959) placed this species in the genus Laeonereis because of the strong resemblance to L. pandoensis Monro, 1937 . Pettibone (1971) noted that holotype was incomplete; also, she highlighted a large number of paratypes ranging from 21 chaetigers and 2 mm in length to 55 chaetigers and 12 mm in length, but only three specimens remain in the paratype lot.

Because of the small size of the type specimens, Pettibone (1971) regarded them as juveniles of L. culveri . ( Dean 2001) examined larger specimens, including topotype material, and found similar features to those of the type specimens, concluding there are enough features to regard L. brunnea as a valid species. Dean (2001) highlighted the following differences between these species: in L. culveri , the anterior cirri are subequal, whereas in L. brunnea the posterodorsal pair of anterior cirri are longer than the remaining ones; in L. culveri , the anterior margin of the prostomium is incised, whereas in L. brunnea it is entire; the neuropodial homogomph falcigers in L. culveri have longer blades and smaller teeth than in L. brunnea . This species has been recorded from Bahia Chatham, Cocos Island, Costa Rica ( Dean et al. 2012), but this record deserves a new evaluation because there is no description or illustration of the only specimen recorded to ensure the identification.

Laeonereis brunnea is the only known species of the genus having supra-acicular homogomph falcigers; also, it was the only species of the genus known from the Pacific Ocean until the recent description of L. watsoni de León-González, Méndez and Navedo, 2017 , a species from the Mexican Pacific, and the differences between them have already been pointed out ( de León-González et al. 2017). Further differences among L. brunnea and the related species, L. watsoni and L. pandoensis , are found in the Remarks sections for those species.

Figures

Figure 5. Foregut, papillae and jaws in Laeonereis species. (a) non-type specimen of L. acuta (ECOSUR- P3102), ventral dissection; (b) non-type specimen of L. pandoensis (ECOSUR-P3103), dorsal dissection; (c) and (d) rounded papillae in area VIII from paratype of L. orensanzi comb. nov. (UANL 7840); (e) rodlike, verticillate papillae from syntype of L. culveri from area IV (USNM 541); (f) everted pharynx from paratype of L. longula sp. nov. (USNM 1490792), labels indicate papillae on the pharyngeal areas; (g) left jaw of the paratype of L. brunnea (USNM 43404), dorsal view; (h) left jaw of the syntype of L. culveri (USNM 541), dorsal view; (i) left jaw of the paratype of L. longula sp.nov. (USNM 1490792), dorsal view; (j) left jaw of L. orensanzi comb. nov. (UANL 7840), dorsal view; (k) left jaw of non-type of L. pandoensis (ECOSUR-P3103), dorsal view. Dark areas in (a) and (b) are due to remnants of Shirlastain staining; (f) is stained with methyl green. Scale bars: a, b = 0.5 mm; c–e, j = 25 µm; f–i, k = 0.1 mm. Abbreviations:Es, oesophagus; Jw, jaw; Pa, papilla; Ph, pharynx; Pp, palpophore; Ps, palpostyle.

Figure 6. Arrangement of pedal glands in Laeonereis species. Abbreviations: DoG = dorsal gland; LoG = lower distal pedal gland; MeG = medial pedal gland; PrG = proximal pedal gland; UpG = upper distal pedal gland.

Figure 11. Laeonereis brunnea Hartmann-Schröder, 1959. (a–c), paratypes (USNM 43404); d–f, nontype (MCZ 34777). (a) whole specimens, dorsal view; (b) anterior end, dorsal view; (c) anterior end, dorsal view; (d) whole specimen, dorsal view; (e) anterior end, dorsal view; (f) posterior end, dorsal view. Scale bars: a–f = 0.5 mm.

Figure 12. Laeonereis brunnea Hartmann-Schröder, 1959. (a–j), paratypes of Laeonereis brunnea (USNM 43404). (a) chaetiger 1, right parapodium; (b) chaetiger 9, left parapodium; (c) chaetiger 10, left parapodium; (d) chaetiger 20, right parapodium; (e) chaetiger 38, right parapodium; (f) chaetiger 34, right parapodium; (g) supra-acicular homogomph falciger, chaetiger 1; (h) sub-acicular homogomph falciger, chaetiger 1; (i) sub-acicular homogomph falciger, chaetiger 9; (j) sub-acicular homogomph falciger, chaetiger 38. Scale bars: a, f = 50 µm; b–e = 0.1 mm; g–j = 5 µm.