Reappraisal of the status of two recently described western Atlantic species of sand crabs (Anomura: Albuneidae)

Abstract

Evidence is provided to support the synonymy of two species of sand crabs (Anomura: Albuneidae). Zygopa lalanai Ortiz, 2015 is a synonym of Zygopa michaelis Holthuis, 1961 and Lepidopa boykoi Ortiz, Tello-Musi and Morales-Moreno, 2018 is a synonym of Lepidopa benedicti Schmitt, 1935. Each of the recently described species was based on a single specimen collected well within the range of their respective senior synonyms.

Keywords:
Caribbean; Cuba; Gulf of Mexico; Lepidopa; synonymy; Zygopa

INTRODUCTION

Two species of sand crabs from the Caribbean and the Gulf of Mexico were recently described by Manuel Ortiz and colleagues (Ortiz, 2015; Ortiz et al., 2018). A review of these publications shows that both species are synonyms of previously described species known from these regions. Zygopa lalaniOrtiz, 2015 is a synonym of Zygopa michaelisHolthuis, 1961 and Lepidopa boykoiOrtiz, Tello-Musi and Morales-Moreno, 2018 is a synonym of Lepidopa benedictiSchmitt, 1935. Evidence is presented herein to support these synonymies.

MATERIAL AND METHODS

Material from the American Museum of Natural History, New York (AMNH), Rijksmuseum van Natuurlijke Historie (RMNH, now Naturalis), Leiden, The Netherlands, and University of Louisiana at Lafayette (USLZ) was previously examined (Boyko, 2002). As the photographs and line drawings from Ortiz (2015) and Ortiz et al. (2018) provided sufficient information for required comparative analysis, it was not necessary to borrow the type material from the Colección Nacional de Crustáceos, Instituto de Biología, Universidad Nacional Autónoma de México (CNCR). Images were constructed in Adobe Photoshop.

SYSTEMATICS

Order Decapoda Latreille, 1802

Infraorder Anomura MacLeay, 1838

Superfamily Hippoidea Latreille, 1825

Family Albuneidae Stimpson, 1858

Subfamily incertae sedis

Genus Zygopa Holthuis, 1961

Zygopa michaelis Holthuis, 1961

(Figs. 1, 2)

Figure 1.
Zygopa lalanaiOrtiz, 2015, holotype male (CNCR 27818) (A, B) and Zygopa michaelisHolthuis, 1961, lectotype female (RMNH 14501) (C, D). A) Dorsal view. B) Close-up of ocular peduncles. C) Carapace, dorsal view. D) Close-up of ocular peduncles. Not to scale. A, B modified from Ortiz (2015); C, D modified from Boyko, 2002.

Figure 2.
Zygopa lalanaiOrtiz, 2015, holotype male (CNCR 27818) (A-D) and Zygopa michaelisHolthuis, 1961, paralectotype male (RMNH 14502) (E-H). A) Left pereopod II, lateral view. B) Left pereopod III, lateral view. C) Left pereopod IV, lateral view. D) Telson, dorsal view. E) Right pereopod II, lateral view. F) Left pereopod III, lateral view. G) Left pereopod IV, lateral view. H) Telson, dorsal view. Not to scale. A-D modified from Ortiz (2015); E-F modified from Boyko, 2002.

Zygopa michaelisHolthuis, 1961: 22-26, figs. 1, 2. - Boyko, 2002: 204-210, figs. 66, 67 (and references therein).

Zygopa cf. michaelisOrtiz et al., 2013: 33, figs. 1e, 1l, 5a, 5b. - Lalana et al., 2014: 127.

Zygopa lalanaiOrtiz, 2015: 84-91, figs. 1b, 2-7 (new synonym). - Diez and Espinosa, 2018: 140.

Remarks. Zygopa lalanai was purportedly distinguished from Z. michaelis by the shape of the ocular peduncles (tapered vs. rounded distally; Fig. 1B vs. 1D), but this is the only character that appears to differ between the holotype (and only specimen) of Z. lalanai and the numerous known specimens of Z. michaelis (see Boyko, 2002). The carapace groove (CG) pattern is the same in both species, as evidenced by a comparison of the photographic fig. 7a in Ortiz (2015; Fig. 1A) and fig. 66a in Boyko (2002; Fig. 1C herein); note that the CGs are depicted inaccurately in the line drawing of Ortiz (2015: fig. 2a) when compared to the photograph (Ortiz, 2015: fig. 7a; Fig. 1A). The dactyli of pereopods II and IV are identical in the two species (compare Ortiz, 2015: fig. 4b, d with Boyko, 2002: fig. 67b, d; Fig. 2A, C vs. 2E, G) as is the dactylus of pereopod III (see Boyko, 2002: fig. 67c; Fig. 2F herein), although in that case the photograph of the ventral view of the holotype of Z. lalanai (see Ortiz, 2015: fig. 7b) has to be used because the line drawing (fig. 4c; Fig. 2B) is not accurate. The shape of the telson is also the same in the two species (compare Ortiz, 2015: fig. 5d and Boyko, 2002: fig. 67f; Fig. 2D vs. 2H). The line drawings of the dactyli of pereopods II-IV as given fig. 6 of Ortiz (2015) are not useful and appear to have been drawn freehand; they are highly inaccurate as evidenced by comparison with the other figures and photographs.

Zygopa michaelis is known from both coasts of Florida, USA, to Brazil, in 4.0-73.2 m depth; the holotype of Z. lalanai was collected off Cuba in 6-8 m depth, a locality well within the known range of Z. michaelis.

As the only apparent difference between Z. lalanai and Z. michaelis is in the degree of the tapering of the ocular peduncles, this must be considered intraspecific variation, possibly age, size, or even preservation related, and the two species are synonymous. Zygopa at present contains only two valid species: Z. michaelis and Zygopa nortoni Serène and Umali, 1965 (known from the Philippines and New Caledonia, ranging to 60 m depth) (Boyko, 2002).

Subfamily Lepidopinae Boyko, 2002

Genus Lepidopa Stimpson, 1858

Lepidopa benedicti Schmitt, 1935

(Figs. 3, 4)

Figure 3.
Lepidopa boykoiOrtiz, Tello-Musi and Morales-Moreno, 2018, holotype female (CNCR 34795) (A) and Lepidopa benedictiSchmitt, 1935, ovigerous female (AMNH 14425) (B). A) Dorsal view. B) Carapace, dorsal view. Double headed arrow indicates misplaced CG 6 and 7 in A; single headed arrow indicates incorrectly drawn dactylus of pereopod III. Not to scale. A modified from Ortiz et al. (2018); B modified from Boyko (2002).

Figure 4.
Lepidopa boykoiOrtiz, Tello-Musi and Morales-Moreno, 2018, holotype female (CNCR 34795) (A-C) and Lepidopa benedictiSchmitt, 1935, female (UNLZ 2122) (D-F). A) Left pereopod II, lateral view. B) Left pereopod III, lateral view. C) Left pereopod IV, lateral view. D) Left pereopod II, lateral view. E) Left pereopod III, lateral view. F) Left pereopod IV, lateral view. Not to scale. A-C modified from Ortiz et al. (2018); D, F modified from Boyko (2002).

Lepidopa benedictiSchmitt, 1935: 210. - Boyko, 2002: 172-179, fig. 56, 57 (and references therein).

Lepidopa boykoiOrtiz, Tello-Musi and Morales-Moreno, 2018: 50-58, figs. 2-5 (new synonym).

Remarks.Ortiz et al. (2018) distinguished the holotype and only specimen of L. boykoi from other species in the genus found in the Gulf of Mexico and Caribbean in their key to species using the following set of characters: “pedúnculos oculares rectangulares; con corneas presentes en sus ángulos basales internos; tacón del dactilo del pereópodo I redondeado; borde ventral distal del dactilo cubierto de setas largas cuvadas.” However, none of these are unique to this specimen.

Rectangular ocular peduncles are found on several species in the genus, including L. benedicti and the pigmentation found in the proximomesial corner of the ocular peduncles (e.g., Fig. 3A) is only an artifact of preservation (see Remarks under various species in Boyko, 2002 where dispersal of pigments is noted). It is unclear what “tacón del dactilo del pereópodo I redondeado” (heel of pereopod dactyl I rounded) means as there is no heel present on pereopod I; it is possible the original description meant to refer to pereopod II, which does have a rounded heel as also seen in L. benedicti and several other species of Lepidopa. The notation of long curved setae on the ventral edge of the dactylus (which dactylus the descriptions refer to is not clear, perhaps all of them) is not diagnostic, as this feature is found in all species in the genus. The drawings of the whole animal (e.g., Ortiz et al., 2018: fig. 1b and inset) are of limited utility and comparison of the photo of the dorsal view (Ortiz et al., 2018: fig. 5a, c), despite its suboptimal angle and small size, clearly shows that at least some of the carapace grooves (CG) are inaccurately placed or excluded from the line drawings. The most glaring error is that CGs 6 and 7 are placed much too posteriorly on the carapace in the line drawing (Fig. 2A vs. 2B herein). The line drawing shows an incomplete submarginal groove which is also seen in L. benedicti; this is not visible in the photograph of Ortiz et al. (2018). The drawings of the individual parts of the holotype appear more accurate renderings, although fig. 4e of pereopod III clearly shows that the dactyl of this same appendage is drawn inaccurately in fig. 1b and the tip of the heel in fig. 4f appears broken (Fig. 3B). Overall, the shape of the dactyli of pereopods I-IV matches those of L. benedicti (Fig. 4A-C vs. 4D, E).

Lepidopa benedicti is known from the central Atlantic coast of Florida, USA, and Gulf of Mexico south to Veracruz, Mexico, in up to 3 m depth (Boyko, 2002). The holotype of L. boykoi was also collected from the littoral zone of Veracruz, Mexico, at the southernmost known edge of the species’ range.

When all the above similarities, both morphological and distributional, are considered, L. boykoi is clearly a synonym of L. benedicti. The author of the present note profoundly regrets to synonymize this species (for obvious reasons), but it seems unavoidable.

DISCUSSION

Although it is regrettable that these two recently described species must enter into synonymy, this highlights an important recommendation when it comes to describing new species of albuneids and, indeed all species: it is inadvisable to describe a new species from a single specimen, especially when the specimen occurs within the range of known congeners unless the specimen exhibits multiple distinctive characters that clearly distinguish it from all previously described species in the genus (e.g., Boyko, 2020).

ACKNOWLEDGEMENTS

Thanks to Darryl Felder (University of Louisiana at Lafayette) for discussions about the identity of Lepidopa boykoi.

REFERENCES

• Boyko CB 2002. A worldwide revision of the recent and fossil sand crabs of the Albuneidae Stimpson and Blepharipodidae, new family (Crustacea: Decapoda: Anomura: Hippoidea). Bulletin of the American Museum of Natural History, 272: 1-396. http://hdl.handle.net/2246/436
  » http://hdl.handle.net/2246/436
• Boyko CB 2020. New records of sand crabs (Crustacea: Decapoda: Albuneidae and Blepharipodidae) from the western Pacific with description of two new species of Paralbunea Serène, 1977. Zoological Studies, 59: 15. https://doi.org/10.6620/ZS.2020.59-15
  » https://doi.org/10.6620/ZS.2020.59-15
• Diez YL and Espinosa J 2018. New data on the distribution of crabs (Decapoda: Anomura and Brachyura) in Cuba. Revista de Investigaciones Marinas, 38(1): 139-158.
• Holthuis LB 1961. Notes on American Albuneidae (Crustacea Decapoda, Anomura) with the description of a new genus and species. Proceedings Koninklijke Nederlandse Akademie van Wetenschappen, series C, Biological and Medical Sciences, 64(1): 21-36. https://decapoda.nhm.org/pdfs/26893/26893.pdf
  » https://decapoda.nhm.org/pdfs/26893/26893.pdf
• Lalana R.; Ortiz M and Varela C 2014. Segunda adición a la lista de los crustáceos (Arthropoda: Crustacea) de aguas Cubanas. Revista de Investigaciones Marinas, 34(1): 121-131. https://revistas.uh.cu/rim/article/view/6644
  » https://revistas.uh.cu/rim/article/view/6644
• Latreille PA 1802. Histoire Naturelle, Générale et Particulière des Crustacés et des Insectes. Ouvrage Faisant suite à l'Histoire Naturelle Générale et Particulière, Composée par LeClerc de Buffon, et Rédigée par C.S. Sonnini, Membre de Plusieurs Sociétés Savantes. Paris, F. Dufart, vol. 3, 468p. https://www.biodiversitylibrary.org/item/80064#page/5/mode/1up
  » https://www.biodiversitylibrary.org/item/80064#page/5/mode/1up
• Latreille PA 1825. Familles naturelles du règne animal, exposé succinctement et dans un ordre analytique avec l'indication de leurs genres. Paris, J. B. Baillière, 570 p. https://doi.org/10.5962/bhl.title.16094
  » https://doi.org/10.5962/bhl.title.16094
• MacLeay WS 1838. Illustrations of the Annulosa of South Africa. On the brachyurous decapod Crustacea. Brought from the Cape by Dr. Smith. In: Smith, A. (Ed.), Illustrations of the Zoology of South Africa; consisting chiefly of Figures and Descriptions of the Objects of Natural History Collected during an Expedition into the Interior of South Africa, in the Years 1834, 1835, and 1836; fitted out by “The Cape of Good Hope Association for Exploring Central Africa”. Published under the Authority of the Lords Commissioners of Her Majesty's Treasury, London, vol. 5, p. i-iv + 53-71, pls. 2, 3. https://www.biodiversitylibrary.org/item/136741#page/61/mode/1up
  » https://www.biodiversitylibrary.org/item/136741#page/61/mode/1up
• Ortiz M 2015. Una nueva especie de cangrejo topo ciego del género Zygopa Holthuis, 1961 (Crustacea, Decapoda, Anomura) de Cuba. Novitates Caribaea, 8: 82-94 .https://doi.org/10.33800/nc.v0i8.45
  » https://doi.org/10.33800/nc.v0i8.45
• Ortiz M; Ocaña F and Lalana R 2013. Clave ilustrada para identificar los cangrejos topos (Decapoda, Anomura, Hippoidea) de las aguas marinas Cubanas, con un nuevo registro.” Revista Cubana de Ciencias Biológicas, 2(2): 31-40. https://revistas.uh.cu/rccb/article/view/1945/1723
  » https://revistas.uh.cu/rccb/article/view/1945/1723
• Ortiz M.; Tello-Musi JL and Morales-Moreno A 2018. Especie nueva de cangrejo de arena del género Lepidopa en Veracruz, México, y una clave illustrada de las especies citadas para el Golfo de México el Mar Caribe. Novitates Caribaea, 12: 49-62. https://doi.org/10.33800/nc.v0i12.84
  » https://doi.org/10.33800/nc.v0i12.84
• Schmitt WL 1935. Crustacea Macrura and Anomura of Porto Rico and the Virgin Islands. Scientific Survey of Porto Rico and the Virgin Islands, New York Academy of Sciences, 15(2): 125-227. https://decapoda.nhm.org/pdfs/12429/12429.pdf
  » https://decapoda.nhm.org/pdfs/12429/12429.pdf
• Serene R and Umali AF 1965. A review of Philippine Albuneidae, with descriptions of two new species. Philippine Journal of Science, 94(1): 87-116, 6 pls.
• Stimpson W 1858. Prodromus descriptionis animalium evertebratum, quae in Expeditione ad Oceanum Pacificum Septentrionalem, a Republica Federata missa, Cadwaladaro Ringgold et Johanne Rodgers Ducibus, observavit et descripsit. Pars VII. Crustacea Anomoura. Proceedings of the Academy of Natural Sciences of Philadelphia, 10: 225-252 [ 63-90 in separate]. https://www.biodiversitylibrary.org/item/183045#page/245/mode/1up
  » https://www.biodiversitylibrary.org/item/183045#page/245/mode/1up

• Zoobank:

  http://zoobank.org/urn:lsid:zoobank.org:pub:F618A975-81D0-438F-A753-D7B1B6218F23

ADDITIONAL INFORMATION AND DECLARATIONS

Edited by

Associate Editor:

Kareen Schnabel

Data availability

Unlimited.

Publication Dates

• Publication in this collection
  04 Sept 2023
• Date of issue
  2023

History

• Received
  04 Jan 2023
• Accepted
  27 Mar 2023