Laeonereis nota ( Treadwell, 1941 )

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 : 419-425

publication ID	https://doi.org/ 10.1080/00222933.2021.1903601
publication LSID	lsid:zoobank.org:pub:830E06E0-858C-4952-9FED-761BB77A75C6
persistent identifier	https://treatment.plazi.org/id/03DB879A-161F-7964-0C8C-FD6BDF1EFD64
treatment provided by	Plazi
scientific name	Laeonereis nota ( Treadwell, 1941 )
status

Treatment

Laeonereis nota ( Treadwell, 1941) View in CoL

( Figures 6 View Figure 6 , 17 View Figure 17 (a–e), 18(a–d), 19(a–l), and 20(a–h)

Leptonereis nota Treadwell 1941: 1–3 View in CoL , figs 7–10. de Jesús-Flores et al. 2016: 209–213, figs 2A–F, 3A–D, 4A–F.

Laeonereis culveri Pettibone 1971: 15 View in CoL , fig. 5c, d (partim, non Webster, 1879).

Type locality

Offats Bayou, Galveston, Texas, Gulf of Mexico.

Type material

Gulf of Mexico, Atlantic Ocean. Holotype of Leptonereis nota AMNH 2896 , Offats Bayou, Galveston, Texas, no date, Coll. W.G. Hewatt.

Additional material

USNM 1490824 (3), Wiggam’s Pass, Naples, Florida, Inlet Beach side, 28 December 1958, Coll . C . Long . USNM 1490825 (10), Rock Creek, Naples , Florida, 24 December 1959, Coll . C . Long.

Description

Holotype ( AMNH 2896 About AMNH ) incomplete, 50 mm long, 1 mm wide at chaetiger 10, 83 chaetigers, specimen previously dissected, several parapodia previously removed, pharynx everted ( Figure 17 View Figure 17 (a–e)) . Non-type specimens ( USNM 1490825 ) used for complete description, 52 mm long, 2 mm wide at chaetiger 10, 117 chaetigers ( Figure 18 View Figure 18 (a–c)); one specimen ( USNM 149824 ) found inside a tube made with sand in a soft matrix ( Figure 18 View Figure 18 (d)) . Specimens brownish, body pigmentation faded out in holotype; anterior chaetigers in non-type specimen with a dorsal, transverse light brown line, almost faded out; glandular masses in parapodia and dorsal side of chaetigers visible in holotype ( Figure 17 View Figure 17 (a,c)).

Prostomium hexagonal, wider than long, anterior margin shallowly cleft, dorsal groove wide and reaching anterior pair of eyes ( Figure 17 View Figure 17 (a)); antennae digitiform, as long as dorsal groove ( Figure 17a View Figure 17 ); eyes black, elliptical to reniform, the two pairs subequal Figure 17 View Figure 17 (a)). Achaetous ring 1.5–2.0 times longer than first chaetiger ( Figures 17 View Figure 17 (a), 18(b)); four pairs of anterior cirri, cirrophores inconspicuous, longest pair of cirri reaching chaetiger 1 ( Figures 17 View Figure 17 (a,b), 18(a,b)).

Pharynx everted in holotype ( Figure 17 View Figure 17 (b,e)). Maxillary ring: I = 1–1 tuft of verticillate rod-like papillae; II = 1–1 tuft of verticillate rod-like papillae; III = 3 tufts of verticillate rodlike papillae; IV = 1–1 tuft of verticillate rod-like papillae ( Figure 17 View Figure 17 (b,e)). Oral ring: V = 0, VI = 1–1 triangular papilla; VII–VIII = one ridge row with 5 rounded papillae, 1 papilla on each A–C region ( Figure 17 View Figure 17 (b,e)).

Pattern of pedal glands ( Figure 6 View Figure 6 ). UpG cordiform and as wide as MeG, becoming L-shaped in middle chaetigers. LoG triangular or elliptical and shorter than UpG in anterior chaetigers, becoming shorter in middle chaetigers. MeG rounded and 3 times larger than PoG, subequal 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 19 View Figure 19 (e)), dorsal cirri linguiform. Dorsal ligules subconical, blunt, 1.2 times longer than wide, 2.8 times longer than dorsal cirri, as long as neuropodial postchaetal lobes. Neuroacicular ligules subconical, distally bilobed, twice as wide as long; postchaetal lobes digitiform, as long as wide, twice as long as neuroacicular ligules, 1.2 times longer than neuropodial ventral ligules; neuropodial ventral ligules digitiform, 1.7 times wider than long, 1.7 times longer than ventral cirri. Ventral cirri subconical.

In anterior chaetigers ( Figure 19 View Figure 19 (a,f)), dorsal cirri linguiform. Notopodial dorsal ligules subconical, blunt, 2.3 times wider than long, 3 times longer than dorsal cirri, twice as long as prechaetal lobes; prechaetal lobes digitiform, 1.5 times longer than wide; notopodial ventral ligules digitiform, 1.3 times longer than wide, twice as long as prechaetal lobes, 1.5 times longer than neuropodial postchaetal lobes. Neuroacicular ligules subconical, distally bilobed, as long as neuropodial ventral ligules; postchaetal lobes digitiform, 1.2 times longer than wide, 1.4 times longer than neuroacicular ligules, twice as long as neuropodial ventral ligules; neuropodial ventral ligules digitiform, 3 times wider than long, 2.3 times longer than ventral cirri. Ventral cirri subconical.

In middle chaetigers ( Figure 19 View Figure 19 (b,c,g,h)), dorsal cirri linguiform. Notopodial dorsal ligules digitiform, 1.4–1.6 times wider than long, 4.5 times longer than dorsal cirri, 2.5 times longer than prechaetal lobes; prechaetal lobes digitiform, as long as wide, disappearing quickly towards posterior chaetigers; notopodial ventral ligules subconical, blunt, 1.3 times longer than wide, 1.2–1.5 times longer than notopodial dorsal ligules. Neuroacicular ligules subconical, 1.2 times longer than notopodial ventral ligules, 2.5 times longer than neuropodial ventral ligules; postchaetal lobes absent; neuropodial ventral ligules digitiform, 4.5 times wider than long, 2.6 times longer than ventral cirri. Ventral cirri subconical.

In posterior chaetigers ( Figure 19 View Figure 19 (d,i,j)), dorsal cirri linguiform. Notopodial dorsal ligules digitiform to subconical, 1.6 times wider than long, 3.2 times longer than dorsal cirri; prechaetal lobes absent; notopodial ventral ligules subconical, 1.5 times longer than notopodial dorsal ligules, twice as long as wide, 1.0–1.5 times longer than neuroacicular ligules. Neuroacicular ligules subconical, 1.3 times longer than wide, 3–5 times longer than neuropodial ventral ligules; postchaetal lobes absent; neuropodial ventral ligules digitiform, 4.2 times wider than long, 10–11 times longer than ventral cirri. Ventra cirri subconical.

In posteriormost chaetigers ( Figure 19 View Figure 19 (k,l)), dorsal cirri linguiform. Notopodial dorsal ligules subconical, as long as wide, 3 times longer than dorsal cirri, half as long as notopodial ventral ligules, becoming shorter in posteriormost chaetigers; notopodial ventral ligules subconical, 1.7–2.0 times longer than wide, as long as neuroacicular ligules. Neuroacicular ligules subconical, 1.0–1.3 times wider than long, 3 times longer than neuropodial ventral ligules; postchaetal lobes absent; neuropodial ventral ligules subconical, 3.7–4.7 times wider than long, 6 times longer than ventral cirri. Ventral cirri subconical.

Notopodia homogomph spinigers. Neuropodia homogomph spinigers in supraacicular fascicles, homogomph spinigers and falcigers in sub-acicular fascicles; subacicular homogomph falcigers absent in anterior chaetigers.

Notopodial and neuropodial homogomph spinigers pectinate, minute teeth, decreasing in size towards distal end ( Figure 20 View Figure 20 (a–d)); sub-acicular spinigers with teeth slightly longer than notopodial and supra-acicular ones ( Figure 20 View Figure 20 (a–d)). Neuropodial homogomph falcigers pectinate, minute teeth, distal tooth stout and hook-like ( Figure 20 View Figure 20 (f–h)), appearing from chaetigers 15–20; blades 11–12 times longer than wide in anterior chaetigers, becoming 18 times longer than wide towards posterior chaetigers ( Figure 20 View Figure 20 (g,h)); blades slightly increasing in size due to blades increasing their length from upper to lower positions in the same fascicle.

Pygidium funnel-shaped; anal cirri cirriform, 2–3 times longer than width of pygidium ( Figure 18 View Figure 18 (c)).

Remarks

The original description by Treadwell (1941) agrees well with the current description, with the following differences: (1) the original description stated the longest pair of anterior cirri reaches chaetiger 3 (‘fourth somite’), whereas in the specimens examined here they reach the end of chaetiger 1; the original description noted the presence of neuropodial postchaetal lobes in posterior chaetigers, but in the specimens examined they are absent in these chaetigers. Treadwell (1941) placed this species in the genus Leptonereis because of the lack of paragnaths in the pharynx, but he overlooked the presence of papillae, as Pettibone (1971) highlighted later. Hartman (1951) regarded Leptonereis nota as a synonym of Laeonereis culveri , but no comments about this were made; illustrations in Hartman’s (1951) work correspond to the species L. longula sp. nov., probably based on specimens from Lemon Bay, Sarasota, Florida. Pettibone (1971) followed this decision without further argumentation. After this, de Jesús-Flores et al. (2016) examined topotype and additional specimens of both L. culveri and L. nota and rejected this synonymy, arguing differences in parapodial morphology are taxonomically significant; these differences are discussed in the Remarks section of L. acuta above. The examination of specimens from Chetumal Bay demonstrated that specimens are very similar to those from the Gulf of Mexico, especially in body measurements such as body size and the number of chaetigers, and in parapodial and chaetal morphology, as found in a previous work ( de Jesús-Flores et al. 2016); de Jesús-Flores et al. (2016) proposed dispersion via migratory birds. Finally, the same authors suggested that pigmentation in the holotype is a preservation artefact that likely could be removed by brushing the specimen ( de Jesús-Flores et al. 2016); however, the dark pigmentation of the body and glands is not an artefact, and additional specimens have a similar body colouration.

Laeonereis nota differs from L. culveri in the following features: in anterior chaetigers of L. nota , notopodial dorsal ligules are subconical and 3 times longer than dorsal cirri, whereas in L. culveri they are lanceolate and 6–7 times longer than dorsal cirri; in middle chaetigers of L. nota , notopodial ventral ligules are longer than notopodial dorsal ligules, whereas in L. culveri they are shorter; in middle and posterior chaetigers of L. nota , the notopodial dorsal ligules are 3.2–4.5 times longer than dorsal cirri and the notopodial ventral ligules are subequal to neuroacicular ones, whereas in L. culveri the notopodial dorsal ligules are 5–8 times longer than dorsal cirri and notopodial ventral ligules are longer than neuroacicular ones.

Laeonereis nota is also similar to L. pandoensis , but some differences can be noted: in anterior chaetigers of L. nota , the notopodial dorsal ligules are 3 times longer than the dorsal cirri, whereas in L. pandoensis they are 4 times longer; in middle and posterior chaetigers of L. nota , the notopodial ventral and neuroacicular ligules are subequal, whereas in L. pandoensis the notopodial ventral ligules are 1.5 times longer than neuroacicular ones; in L. nota , the blades of the neuropodial homogomph falcigers become wider towards the distal end, whereas in L. pandoensis they become narrower.