BARBOURIA YANEZI SP. NOV., A NEW SPECIES OF CAVE SHRIMP (DECAPODA, BARBOURIIDAE) FROM COZUMEL ISLAND, MEXICO

BARBOURIA YANEZI SP. NOV., A NEW SPECIES OF CAVE SHRIMP (DECAPODA, BARBOURIIDAE) FROM COZUMEL ISLAND, MEXICO BY LUIS M. MEJÍA 1 ), ESTEBAN ZARZA and MARILÚ LÓPEZ Lab. Bioespeleología y Carcinología, Universidad de Quintana Roo Cozumel (UQROO-Cozumel), DDS, Dpto. Ciencias y Humanidades, Avenida Andrés Quintana Roo s/n, C. P. 77640, Cozumel, Quintana Roo, Mexico ABSTRACT A new species of the genus Barbouria from Cozumel Island, Mexico, is described. The new species, Barbouria yanezi is similar to Barbouria cubensis in exhibiting a cornea narrower than the eyestalk, and in its telson ornamentation, but differs from the latter species in the number of rostral spines, the proportions of the scaphocerite, the relative proportions of the carpus and propodus of the first and second pereiopods, the relationship between the appendices masculina and interna, and in size: it is larger than B. cubensis. The geographical relationship between the species is discussed. RESUMEN Se describe una nueva especie del género Barbouria de la isla de Cozumel, México. Barbouria yanezi nueva especie, es similar a Barbouria cubensis en mostrar una córnea más estrecha que el tallo ocular y la ornamentación del telson, pero difiere de ésta en el número de espinas rostrales, proporciones del escafocerito, proporciones relativas del carpus y propodio del primero y segundo pereiópodo, así como la relación entre el apéndice masculina e interna, además es más grande que B. cubensis. La relación geográfica entre estas especies es discutida. INTRODUCTION The monotypic genus Barbouria has been reported from various Caribbean islands. Initially, the genus was recorded only in Cuba (Von Martens, 1872; Rathbun, 1912), but by the end of the nineteenth century, Barbouria cubensis (Von Martens, 1872) had also been found on the Turks and Caicos Islands, Bermuda, Cayman Brac, and the Bahamas (Hobbs et al., 1977; Hart & Manning, 1981; Juarrero de Varona & Gómez, 1995), from several localities in anchialine caves on 1 ) e-mail: luismejia@uqroo.mx Koninklijke Brill NV, Leiden, 2008 Crustaceana 81 (6): 663-672 Also available online: www.brill.nl/cr

664 LUIS M. MEJÍA, ESTEBAN ZARZA & MARILÚ LÓPEZ those islands (Holthuis, 1974; Buden & Felder, 1977; Hobbs et al., 1977; Hobbs, III, 1978; Hart & Manning, 1981; Manning & Hart, 1984; Iliffe, 2003; Álvarez et al., 2004). Recently, some samples were collected from anchialine caves on the Yucatán Peninsula, but these were only identified at the generic level (as Barbouria sp.; Bishop & Illife, 2005). Previously, B. cubensis has been considered a hippolytid shrimp, until Manning & Hart (1984) redefined the generic characters and also detailed the status of the genera Barbouria, Janicea, Somersiella, Parhippolyte, andligur. Subsequently Christoffersen (1987), proposed that Barbouria be located in a new family, the Barbouriidae. Although few samples have been collected, in those places where these shrimps have been found, they were always abundant. Hobbs III (1978) reported strong variation in the rostral teeth: most samples had included only males, which show such variation; it was not until 1978 that Hobbs could describe the female and confirm similar variation. Several male and female shrimps from a cenote on Cozumel Island are described here as a new species of Barbouria, and its relationships with Barbouria cubensis are discussed. The type specimens are deposited in the National Crustacean Collection (CNCR) of the Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, and in the Lab. Bioespeleología y Carcinología, Universidad de Quintana Roo Cozumel. SYSTEMATICS Barbouria yanezi new species (figs.1,2) Material examined. Holotype:, 8 March 2006; coll. E. Zarza-González & L. M. Mejía-Ortíz; Cenote Tres Potrillos, Cozumel Island, Mexico (20 27 05 N86 59 15 W), 26 m depth; CNCR 24678. Allotype:, 8 March 2006; same collectors and locality as holotype; CNCR 24679. Paratypes: Three, 3 ; 30 March 2006; same collectors as allotype; CNCR 24680. Eleven, 12 ; 12 December 2004; colls. L. M. Mejía-Ortíz, P. Sabido Itza, and W. Uc-Huchin; BC-UQROO-70. Fifteen ; 20 November 2006; colls. E. Zarza-González, L. M. Mejía-Ortíz, and C. Bulit; BC-UQROO-150. All paratypes were collected at the type locality. Description of holotype male. Medium-sized shrimp, maximum total length 64 mm. Rostrum slightly large, straight, tip almost reaching distal border of second antennular segment; dorsal margin bearing 5 teeth, 3 in postorbital position, 5 teeth on ventral margin (fig. 1A). Carapace smooth, maximum length 20.9 mm, with antennal spine equal to banchiostegal spine. Branchiostegal groove shallow.

BARBOURIA YANEZI NOV. 665 Fig. 1. Barbouria yanezi new species, male holotype, CNCR 24678. A, lateral view; B, distal portion of antennal peduncle; C, second pleopod with appendix masculina; D, telson and uropods. Scale bars represent: A, D, 1 cm; B, C, 0.5 cm.

666 LUIS M. MEJÍA, ESTEBAN ZARZA & MARILÚ LÓPEZ Abdomen smooth, first somite with anterior margin of pleuron straight, second somite with rounded pleura, somites 3-5 with posterior angle of pleura acute, and each with a posterolateral tooth (fig. 1A). Posteroventral margin of third and fourth somites bearing setae on ventral border. Sixth somite 2.2 times as long as fifth. Telson 1.4 times as long as sixth somite, almost equal to uropodal rami; bearing three pairs of dorsal spines, first pair in its proximal third, second pair in middle section, and the third pair almost on posterior border of telson; posterior margin rounded, bearing one pair of lateral spines, larger than inner pair; external pair 4.6 times as long as internal pair. Eyes pigmented, cornea narrower than stalk. Antennules with acute stylocerite not reaching distal margin of first peduncular segment (fig. 1b). First antennular segment with concave depression to fit eye. Second antennular segment cylindrical. Antennae with basicerite smooth. Scaphocerite 2.47 times as long as wide, distolateral spine short, widely separated from distal margin of main blade (fig. 1D). Mandibles with unsegmented palp; molar process without teeth, but bearing a slightly serrate apical border (fig. 2A). Maxillules with setae on palp, inner border with setae; anterior lacinia approximately oval, setae on mesial margin; distal margin with six teeth and a row of fine setae, lateral margin straight, devoid of setae; posterior lacinia tapering distally, curved inwards with four setae, distal half covered with setae (fig. 2B). Maxillae with scaphognathite bordered with plumose setae, anterior lobe narrower and longer than posterior one; palp with four setae distally, directed anteriorly; endite bilobed, divided along its length, posterior lobe narrower than anterior, and both with terminal tufts of setae (fig. 2C). First maxilliped with bilobed endite, bearing marginal and submarginal setae along margin, and a row of setae on surface of distal lobe. Exopod slender, 4 times as long as palp, with setae on base and four long setae on apical area; palp simple, with setae distally, shorter than endite; caridean lobe large, fused to base of exopod, bearing long setae along margin; epipodite trapezoidal (fig. 2D). Second maxilliped subpediform, podobranch present, well developed; endopodite 4-segmented, distal two segments oriented mesially, gnathal border with marginal setae and submarginal setae; exopodite slender, almost twice as long as endopodite, tip bearing long, plumose setae (fig. 2E). Third maxilliped pediform, slender, overeaching scaphocerite; arthrobranch present, well developed (fig. 2F). Endopodite 3-segmented, with scattered setae along margin; first segment slender, 1.9 times as long as second segment; second segment 1.2 times as long as third, distal margin with teeth ending in a nail. Exopodite slender, flat, originating from first segment of endopodite, and shorter than this, bearing long setae distally.

BARBOURIA YANEZI NOV. 667 Fig. 2. Barbouria yanezi new species, male holotype, CNCR 24678. A, right mandible; B, left maxillule; C, right maxilla; D, first maxilliped; E, second maxilliped; F; third maxiliped; G-K, first through fifth pereiopods, respectively. Scale bar represent: A-E, 0.5 cm; F-K, 1 cm.

668 LUIS M. MEJÍA, ESTEBAN ZARZA & MARILÚ LÓPEZ First pereiopods shorter than all other pereiopods, and slightly robust, with tufts of setae on articulation of dactylus and fixed finger. Tip of fingers not surpassing distal margin of scaphocerite; palm slightly compressed, almost as long as dactylus; dactylus curved inwards; carpus 2 times length of palm, 0.7 times length of merus (fig. 2G). Second pair of pereiopods subequal in size, without spines. Palm semicylindrical, as long as wide, and with length equal to that of dactylus; carpus 26 times palm length, 2.28 times as long as merus; both multiarticulate, carpus with 23 and merus with 11 segments, therefore ischium also multiarticulate in the distal portion with 4 segments; ischium 1.08 times length of merus. Fingers not gaping, cutting margins covered with rows of tufts of setae, both propodus and dactylus with setae on apical area (fig. 2H). Propodus and dactylus of third pereiopod sparsely pilose; distal spines on articulation with dactylus. Propodus 6.8 times length of dactylus, 1.17 times carpus length. Two rows of 8 spines on inner and distal border of merus (fig. 2I), respectively. Fourth pereiopods sparsely pilose; propodus 9 times length of dactylus, 1.5 times as long as carpus; with two rows of 6 spines on inner and distal border of merus, four setae on propodus-dactylus articulation (fig. 2K). Propodus of fifth pair of pereiopods pilose; two spines on inner border of merus, four setae on propodus-dactylus articulation; propodus 12 times dactylus length, 1.7 times length of carpus (fig. 2J). Appendix masculina 0.6 times length of appendix interna, 11 spines on its apical portion (fig. 2C). Description of allotype female. Similar to holotype but differing in the following characters. Rostrum with six teeth on dorsal margin and three teeth on ventral margin. Second and fifth pereiopods almost of equal length. Etymology. The specific name is given in honor of Germán Yáñez, an indefatigable expert cave diver on Cozumel Island and Yucatán Peninsula, who collected this species for the first time. Ecological notes. The water quality of the Cenote Tres Potrillos (Cozumel) was as follows at the time of collection: light penetrated to 2 m depth, temperature 25.8 C, ph 7.4, and dissolved oxygen 0.1 mg/l and <0.3% saturation. From 10 m depth down, hydrogen sulfide (H 2 S) is a significant component in the water. The deepest part of the cave system is at 38 m. The salinity increased from the superficial fresh water up to 36 ppt at 11 m depth (fig. 3) (Mejía-Ortíz et al., 2007). This cenote also is a habitat for shrimps of the genera Procaris and Agostocaris as well as for amphipods and isopods. While alive, Barbouria yanezi sp. nov. is orange in colour, with prominent, black pigmented eyes. Ovigerous females were not collected.

BARBOURIA YANEZI NOV. 669 Fig. 3. Distribution of Barbouria yanezi new species in the anchialine cave Tres Potrillos on Cozumel Island, Mexico. DISCUSSION The genus Barbouria has been monotypic since 1872 when Von Martens described Barbouria cubensis from a cave between Cojimar and Castillo Morro near Habana, Cuba (Botosaneanu & Holthuis, 1970). It has subsequently been reported from several Caribbean islands (see fig. 4; Holthuis, 1974; Buden & Felder, 1977; Hobbs et al., 1977; Hobbs, 1978; Hart & Manning, 1981; Manning & Hart, 1984; Iliffe, 2003; Álvarez et al., 2004). However, the genus has not been reported from Mexico until 2005, when Bishop & Iliffe (2005) mentioned animals collected in a cenote on the Yucatán Peninsula. Now we have described Barbouria yanezi sp. nov. as a new species of the genus, collected from a cenote on Cozumel Island. We found the following differences in relation to Barbouria cubensis (see table I). The rostrum not reaching the second article of the antennular peduncle, whilst Barbouria yanezi sp. nov. has a longer rostrum that reaches the middle of the second article. The number of dorsal and ventral rostral spines in the new species is higher. The number of segments of the

670 LUIS M. MEJÍA, ESTEBAN ZARZA & MARILÚ LÓPEZ TABLE I Comparison between the species of Barbouria cubensis (Von Martens) and B. yanezi new species B. cubensis B. yanezi sp. nov. Rostrum 5 dorsal teeth, 3 postorbital teeth, 5 ventral teeth not reaching the distal margin of second antennular article 3-7 dorsal teeth, 2-4 postorbital teeth, 3-9 ventral teeth reaching the distal margin of second antennular article Scaphocerite 2.9 times as long as wide 2.47 times as long as wide First pereiopod Merus/carpus 1.11-1.14 1.13-1.34 Propodus/dactylus 2-2.13 1.78-2.32 Palm length/width 1.75-1.82 1.5-2 Second pereiopod Merus/carpus 0.52-0.53 0.49-0.55 Segments carpus 25-31 26-34 Segments ischium 0 4 Appendix masculina 0.75 times length of appendix interna; with 5 spines Carapace length 13.6 mm 14.4 to 20.9 mm 0.6 times length of appendix interna; with 11 spines carpus of the second pereiopod is greater in comparison with Barbouria cubensis; in B. yanezi sp. nov. the ischium is multiarticulate with 4 segments whilst in B. cubensis the ischium is not multiarticulate (figs. 1A, 2H); the appendix masculina is shorter than the appendix interna in Barbouria yanezi sp. nov. (0.6 times) whilst in B. cubensis this proportion is slightly greater (0.75 times); the merus-carpus, propopus-dactylus, and palm length-width proportions in the first pereiopod are larger in Barbouria yanezi sp. nov. than in B. cubensis (table I). Barbouria yanezi sp. nov. occurs in the same geographical region as Barbouria cubensis (fig. 4). However, because they inhabit caves, there obviously is isolation between the populations. The habitat also demands specializations to survive in these extreme, subterranean environments (e.g., adaptation to a high hydrogen sulfide content and a lack of predators). In general, populations of cave animals are quite small, but in contrast to other caves in the Caribbean region we found a substantial population of the new species with abundant females and males. In cases where only a few specimens of Barbouria cubensis have been collected, it was not possible to define differences between the populations, but where many specimens have been collected, the variation proved considerable (Hobbs, 1978). Because of the high variation in the morphological characters of Barbouria cubensis, we think it is possible that several additional species of Barbouria inhabit the Caribbean region, so it will be necessary to collect more material of this decapod from more different localities, in order to better understand its dispersion pattern among the Caribbean islands. If possible, molecular methods should be incorporated.

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