Asymmetrione desultor Markham, 1975

Romero-Rodriguez, Jesús & Álvarez, Fernando, 2023, Parasitic bopyrid isopods of hermit crabs (Anomura, Paguridae) from the Atlantic coast of Mexico, with notes on their reproduction and distribution, European Journal of Taxonomy 861, pp. 132-167 : 144-146

Asymmetrione desultor Markham, 1975

Figs 1 , 2D , 6 , Table 1

Asymmetrione desultor Markham, 1975b: 255–260 , figs 1–4.

? “Bopyrien” – Forest & de Saint Laurent 1968: 74.

Asymmetrione desultor – Markham 1978: 102–103, 115–116, table 1; 1985: 108; 1988: 7, table 1; 2003: 73–74. — Adkison & Heard 1978: 408. — Bourdon 1979: 143–144. — Ross 1983: 167. — Markham & Donath-Hernández 1990: 243. — Camp 1998: 134. — McDermott 1998: 1044; 2001: 629 (in table 2), 635. — Campos 2003: 86. — Boyko & Williams 2004: 357, 359–360, 366–369, 373, 377–378. — Williams & Schuerlein 2005: 101. — Pardo et al. 2009: 2048–2049 (in key). — An et al. 2010: table 1; 2016: table 2. — McDermott et al. 2010: 8. — Williams et al. 2019: 86 (in key).

Material examined

MEXICO • 1 ovigerous ♀ (4.90 mm TL), 1 ♂ (2.50 mm TL); Quintana Roo, Cozumel ; 20º32′39″ N, 86º48′21″ W; 18 Aug. 1987; J.L. Villalobos et al. leg.; host ♂ of Pagurus stimpsoni (A. MilneEdwards & Bouvier, 1893) (7.10 mm SL); J. Romero det. host; CNCR-36488 • 1 juvenile ♀ (1.84 mm TL); Veracruz, El Morro de la Mancha ; 19º35′22″ N, 96º22′45″ W; 27 May 2004; C. Hernández et al. leg.; detached from host; CNCR-36489 .

Distribution

Asymmetrione desultor is widely distributed along the western Atlantic ( Fig. 1 ): from North Carolina and Florida, USA, Antigua, Bahamas, Curaçao, Bonaire, Belize, Colombia to Brazil ( Boyko & Williams 2004), hence its presence in Mexican waters was suggested by Markham & Donath-Hernández (1990); however, the material examined herein is the first evidence that this bopyrid parasitizes hermit crabs from the SW Gulf of Mexico and the Mexican Caribbean. Pagurus stimpsoni is not a new host for A. desultor since Markham (2003) noted that this bopyrid has a wide host range, that includes one species of Diogenidae Ortmann, 1892 ( Paguristes tortugae ) and seven species of Paguridae Latreille, 1802 , one in the genus Iridopagurus de Saint Laurent-Dechancé, 1966 ( Iridopagurus sp. ) and five in Pagurus Fabricius, 1775 ( P. brevidactylus , P. longicarpus , P. provenzanoi Forest & de Saint Laurent, 1968 , P. stimpsoni and P. tortugae ) and another one in Pylopagurus A. Milne-Edwards & Bouvier, 1893 ( Pylopagurus sp. ).

Remarks

The morphology of the adult couple examined (CNCR-36488) ( Figs 2D , 6A–B ) matched well with the characteristics defined for Asymmetrione desultor by Markham (1975b), but the following variations were observed in the female: the first pair of oostegites with inner margin slightly sinuated and with a rounded lobule in the proximal portion ( Fig. 6C ), Markham (1975b: fig. 1f) sketched a similar lobe in his figure but he did not refer to it in the female’s description; as well, the uropods of the female examined were uniramous ( Fig. 6A ) instead of biramous. As far as we know, the maxilliped of this bopyrid has not been described previously thus the following is provided. Maxilliped with anterior segment much larger than posterior one, rectangular in shape with distal margin extending forward but lacking palp or setae and lateral margin folded upwards, posterior segment triangular in shape with long and pointed spur ( Fig. 6D ).

Although the female examined detached from the host was slightly damaged (CNCR-36489), it matched well the description of A. desultor , and was classified as juvenile according to the following features: oostegites not fully developed, barely touching each other in the mid abdominal portion, only the fifth pair overlapping, the barbula had two very small projections on each side and a smooth medial margin, as well as exopods of the pleopods more developed than endopods which in most cases had a fleshy bulge shape.

Reproduction

The average length and width of the embryos recorded for A. desultor are shown in Table 1 . The embryos were in stage I and their sizes ranged from 0.200 to 0.255 mm of length and between 0.182 and 0.218 mm of width. The embryo volume in this developmental stage ranged from 0.0038 to 0.0059 mm 3, thus the average volume calculated ( Table 1 ) is greater than those reported for other bopyrids of comparable sizes (see Romero-Rodríguez & Álvarez 2020).

A prevalence of 66.67% was estimated for A. desultor , but this is based on a very small sample of three hosts, of which two were parasitized.

Figures

Fig. 1. Distribution along the American continent of five bopyrid species that parasite hermit crabs recorded in the Mexican Atlantic. A. Detail of the Atlantic coast of Mexico.

Fig. 2. Dorsal view of ovigerous females of bopyrid isopods that parasites hermit crabs in Atlantic Mexican coasts.A. Anathelges hyptius (Thompson, 1902) (CNCR-36525-C). B. Pseudostegias atlantica Lemos de Castro, 1965 (CNCR-36483). C. Stegias clibanarii Richardson, 1904, stained with methylene blue (CNCR-36487). D. Asymmetrione desultor Markham, 1975 (CNCR-36488). E. Asymmetrione tuxtlaensis sp. nov., with male ventrally attached to pleon (CNCR-36495). F. Bopyrissa wolffi Markham, 1978 (CNCR-36502-A). Scale bars: A–E = 1.0 mm; F = 0.5 mm.

Fig. 6. Asymmetrione desultor Markham, 1975 (CNCR-36488). A. Ovigerous ♀, dorsal view. B. Same, with ♂ attached to pleon, ventral view. C. First oostegite, internal view, posterolateral point damaged. D. Maxilliped, with lateral projection of barbula. Scale bars = 1.0 mm.