Pseudostegias atlantica Lemos de Castro 1965
Creators: name: Romero-Rodriguez, Jesús
name: Álvarez, Fernando
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Bopyridae
Pseudostegias
Pseudostegias atlantica

description: Pseudostegias atlantica Lemos de Castro, 1965
Figs 1, 2B, 4, Table 1
Pseudostegias atlantica Lemos de Castro, 1965: 105–108, figs 1–9.
Pseudostegias atlantica – Markham 1978: 115; 1982: 373; 2003: 72. — Page 1985: 203. — Brasil-Lima 1998: 640. — Williams & Boyko 1999: 720 (in key). — Boyko 2004: 701. — McDermott et al. 2010: 11 (in table 1). — Figueredo et al. 2013: 92–93. — Ribeiro et al. 2019: 1–3, 6, figs 2–3.
Material examined
MEXICO • 1 juvenile ♀ (2.60 mm TL); Veracruz, Los Tuxtlas, Montepío; 18º38′35.23″ N, 95º05′54.43″ W; 19 Feb. 1996; R. Robles leg.; host ♀ of Clibanarius antillensis Stimpson, 1859 (3.40 mm SL); C. Hernández det. host; CNCR-36482 • 1 ovigerous ♀ (4.00 mm TL), 1 ♂ (1.65 mm TL); same locality as for preceding; 19 Feb. 1996; same collector; detached from host; CNCR-36486-A • 1 ovigerous ♀ (3.76 mm TL), 1 ♂ (1.67 mm TL); same collection data as for preceding; detached from host; CNCR-36486-B • 1 ovigerous ♀ (3.92 mm TL), 1 ♂ (1.67 mm TL) Veracruz, El Morro de la Mancha; 19º35′22.79″ N, 96º22′45.21″ W; 19 May 1998; F. Álvarez and R. Robles leg.; host ♀ of Calcinus tibicen (Herbst, 1791) (2.54 mm SL); C. Hernández det. host; CNCR-36483 • 1 juvenile ♀ (3.88 mm TL), 1 ♂ (1.15 mm TL); same locality; 20 Apr. 2006; J.L. Villalobos et al. leg.; host ♂ of same species as for preceding (4.90 mm SL); Y. de los Santos det. host; CNCR-36484 • 1 ovigerous ♀ (3.30 mm TL), 1 ♂ (1.53 mm TL); Veracruz, Isla Verde; 19º11′59.18″ N, 96º04′01.28″ W; 30 Jul. 1965; J. Cabrera leg.; Detached from host (possibly C. antillensis); CNCR-36485.
Distribution
Pseudostegias atlantica is recorded for the first time in Mexico, previously known from Ceará and Alagoas, Brazil (Lemos de Castro 1965; Ribeiro et al. 2019) and Isla Margarita, Venezuela (Figueredo et al. 2013), its distribution range is now extended to the southwestern Gulf of Mexico (Fig. 1). Similarly, the number of known hosts for P. atlantica increases to three: Calcinus tibicen, Clibanarius antillensis
and Paguristes tortugae Schmitt, 1933. In Montepío, Veracruz, P. atlantica co-occurs with the brachial bopyrid Asymmetrione tuxtlaensis sp. nov.
Remarks
The bopyrids examined are morphologically similar to Pseudostegias atlantica (Figs 2B, 4A–C) described by Lemos de Castro (1965). Ribeiro et al. (2019) defined traits not provided in the original description such as the antennae of both sexes and the first pair of oostegites; the maxilliped and barbula are described below.
Maxilliped with anterior segment much larger than posterior one, rounded in shape and lacking palp, posterior segment semi-triangular in shape with rounded borders and round spur (Fig. 4D). Barbula bearing two lateral projections of sinuated outlines on each side; external projection smaller, narrow and bent up; internal one larger, stout and curved; medial margin with two small rounded projections directed to opposite sides (Fig. 4E).
The following variations were observed: in females, the endopods of the five pairs of pleopods were wider than exopods and directed backward (Fig. 4B), in contrast, Lemos de Castro (1965) noted that endopod of pleopods 1–3 is wide and folded inwards, while in pleopods 4–5 is elongated and directed outwards. The first pair of oostegites contrasts with those reported by Ribeiro et al. (2019), the anterior segment is drop-shaped due to the anterior margin extending rather upwards, the posterior segment is larger than the anterior one, rectangular in shape and with posterolateral projection wide, bearing small setae on posterior distal margin (Fig. 4F); the inner margin is thickened in the middle section, similar to that reported by Ribeiro et al. (2019) but bears two projections in the proximal section, one small and triangular in shape and another larger and curved (Fig. 4G). Males (Fig. 2C) were more similar to those illustrated by Lemos de Castro (1965: fig. 5) and only differ from those described by Ribeiro et al. (2019) in the lack of setae in the distal margin of carpus of pereopods 1 and 7.
Two juvenile females were recorded, one of 2.60 mm TL with a cryptoniscus larva between their oostegites (Fig. 4H–I) and another one of 3.88 mm TL paired with a male attached in the marsupium. Both females with dorsolateral bosses scantly developed in pereomeres 1–4 on both sides, oostegites not completely developed and ovoid in shape and pleopods with round endopods that increase in size backward s (Fig. 4I).
Reproduction
The average size of ovigerous females (n = 4) was 3.75 ± 0.31 mm TL; their range sizes are shown in Table 1. The average fecundity of P. atlantica was 217 ± 37.63 embryos, the minimum (177 embryos) and maximum (267 embryos) fecundities were recorded in females of similar sizes (3.92 and 4.00 mm TL, respectively), but carrying embryos of different developmental stages (Table 1). Sizes of embryos in egg stage were larger than those in stage I, the first ones ranged from 0.20 to 0.23 mm of length and between 0.18 and 0.23 mm of width, whilst the length of embryos in stage I varying from 0.15 to 0.22 mm and their width between 0.13 and 0.18 mm. Table 1 shows the average length, width and volume of P. atlantica embryos, which are larger than those recorded for other bopyrids (see RomeroRodríguez & Álvarez 2020).
Males were recorded inside the females’ marsupium, and their average size was 1.63 ± 0.07 mm TL, with a range from 1.53 to 1.67 mm TL. Both female and male sizes were smaller than those reported by Lemos de Castro (1965) in Brazil (5.5 and 3.0 mm, respectively).
One hundred and sixty-two hermit crabs were counted in the samples, of which six were parasitized by P. atlantica, thus prevalence of this bopyrid was of 3.70%.
description: Published as part of 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, pp. 132-167 in European Journal of Taxonomy 861 on pages 139-141, DOI: 10.5852/ejt.2023.861.2073, http://zenodo.org/record/7753757