Lygdamis pechi, Chávez-López, 2022

Chávez-López, Yessica, 2022, New species of sabellariids (Annelida: Sabellariidae) from the Caribbean Sea and the Gulf of Mexico, European Journal of Taxonomy 831, pp. 109-148 : 111-114

Lygdamis pechi sp. nov.

urn:lsid:zoobank.org:act:431F3C52-F1BF-4B86-81D2-A601CCA93204

Figs 1–2

Diagnosis

Seven outer paleae cylindrical at base, flattened sharp tips, and serrate margins. Four inner paleae cylindrical, blunt tips and faintly serrate margins. Median organ shorter than lobes, cylindrical, without lateral eyespots, with truncate and pigmented tip.

Etymology

This species name is after Dr Daniel Guadalupe Pech Pool, head of the BIOMARCCA collection, who kindly lent me the holotype specimen. The species name is a noun in the genitive case ( ICZN 1999, Art. 31.1.2).

Material examined

Holotype MEXICO • complete spec. (body length 5.5 mm); Veracruz, northeast of Tecolutla; 20°45′37.91″ N, 96°57′41.8″ W; depth 47 m; 18 Mar. 2018; ALH leg.; ECOSUR-302 .

Description

BODY. Holotype complete (ECOSUR-302), preserved material colorless, 5.5 mm long, 0.8 mm wide, 17 abdominal segments, caudal peduncle 0.5 mm long ( Fig. 1 ).

OPERCULUM. Opercular disc oblique, two rows of translucent, pale yellow paleae; outer row with 6–7 paleae per lobe, inner row with four paleae per lobe ( Fig. 1A–C ). Outer paleae cylindrical at base with flattened, sharp tip; blade straight with serrated margins ( Fig. 2A–C ). Inner paleae 1.6 times as long as outer paleae, cylindrical; blade straight, with faintly serrate margins and blunt tips ( Fig. 2A, D ). Opercular stalk twice longer than wide ( Fig. 1A–B ). Five to six opercular papillae decrease in size ventrally ( Fig. 1C ); first pair of papillae about four times as long as others, with dark tips ( Fig. 1B ). Nine rows of buccal tentacles. Palps slightly longer than median organ, as long as opercular stalk lobes ( Fig. 1D ). A pair of nuchal hooks, large, sharp ( Fig. 1B–C ). Median ridge with marginal eyespots. Median organ shorter than lobes, almost four times as long as wide, cylindrical, tip truncate and pigmented, without lateral eyespots ( Fig. 1D ).

THORAX. First thoracic segment with one lobe-shaped neuropodium and capillary chaetae ( Fig. 1E ). Second segment with capillary neurochaetae, two triangular-shaped lateral lobes, and paired branchiae.

PARATHORAX. With four segments, all with branchiae. Notopodia with six lanceolate and five capillary chaetae ( Fig. 2E ). Neurochaetae with four lanceolate and five capillaries, half the length of notochaetae ( Fig. 2F ).

ABDOMEN. Abdominal segments with paired branchiae up to segment 4 ( Fig. 1A, F ). Neurochaetae capillary, ornamented with irregular thecal laminar extensions. Notopodia with series of uncini with 6–7 transverse rows of teeth ( Fig. 2G ). Caudal peduncle colorless, small, cylindrical ( Fig. 1F ).

Remarks

Uebelacker (1984) recorded Lygdamis indicus Kinberg, 1867 for the west coast of Florida, northeastern Gulf of Mexico. Her specimens had “14–31 pairs of outer paleae slender, faintly serrate, and distally pointed in juveniles, smooth with tips often bent in adults; …6–16 pairs of inner paleae stouter, blunttipped, smooth in adults, faintly serrate in juveniles; …a median tentacle (or median organ) stout with dark brown tip” ( Uebelacker 1984: 49-5). The faintly serrated outer and inner paleae of specimens that Uebelacker (1984) described as juveniles resemble the opercular paleae of L. pechi sp. nov. However, L. pechi sp. nov. has outer paleae with flattened tips, and fewer opercular paleae (6–7 outer paleae per lobe, four inner paleae per lobe).

Kirtley (1994) included some of the Uebelacker’s records in L. rayrobertsi Kirtley, 1994 from Florida. Kirtley also indicated that the record of L. indicus in the Gulf of Mexico was a misidentification. However, he failed to explain any morphological variations of the opercular paleae described by Uebelacker (1984), so it is not possible to determine whether the juvenile specimen described by Uebelacker also belongs to L. rayrobertsi .

In the brief description of L. rayrobertsi, Kirtley (1994) mentioned smooth outer paleae with sharp, slightly bent, conical tips; broad, flat inner paleae with smooth margins; and a median organ ending in discoidal, pigmented, truncate tip. Lygdamis pechi sp. nov. and L. rayrobertsi share a robust median organ; however, they differ in the morphology of their opercular paleae (see key above).

Kirtley (1994) did not describe the number of opercular paleae of L. rayrobertsi . Dos Santos et al. (2014) recorded L. rayrobertsi (8 mm long) for Brazil and describe it with 14 outer paleae, six inner paleae per lobe and opercular papillae of similar size ( Dos Santos et al. 2014: fig. 2b), whereas L. pechi sp. nov. (5.5 mm long) has only seven outer paleae, four inner paleae per lobe and the first pair of papillae longer than other ones.

Distribution

Gulf of Mexico, northeast of Tecolutla, Veracruz, at 47 m depth ( Fig. 22 ).

Figures

Fig. 1. Lygdamis pechi sp. nov., holotype (ECOSUR-302). A. Complete specimen, dorsal view. B–C. Anterior region, dorsal view. D. Median ridge and median organ, ventral view. E. Thorax and parathoracic region, ventral view.F. Posterior region, dorsal view.Abbreviations: c1t = cirrus 1st thoracic segment; mo = median organ; mr = median ridge; ne = parathoracic neuropodium; nh = nuchal hooks; no = parathoracic notopod; opa = opercular papillae; pa = palps; tf = tentacular filament. Scale bars: A = 0.5 mm; B–F = 200 µm.

Fig. 2. Lygdamis pechi sp. nov., holotype (ECOSUR-302).A. Opercular paleae.B. Outer paleae.C. Detail of the outer paleae tips. D. Inner palea. E. Parathoracic notochaetae. F. Parathoracic neurochaetae. G. Abdominal uncini. Abbreviations: op = outer paleae; ip = inner paleae. Numbers indicate the rows of teeth. Scale bars: A–B = 100 µm; C = 20 µm; D–F = 50 µm; G = 10 µm.

Fig. 22. Localities for studied specimens. A. Caribbean Sea and the Gulf of Mexico. B. South Florida. C. Southeastern Bahamas. The crosses indicate type localities of species previously recorded in the tropical Western Atlantic.