Postilla Published by the PEABODY MUSEUM OF NATURAL HISTORY YALE UNIVERSITY New Haven, CT 06520-8118 Number 221 29 February 2000 The genus Maera (Crustacea: Amphipoda: Melitidae) from Bermuda Sandro Ruffo Museo Civico di Storia Naturale Lungadige Porta Vittoria 9 I-37129 Verona, Italy Traudl Krapp Forschungsinstitut und Museum Alexander Koenig Adenauerallee |60 D-53113 Bonn, Germany Michael F. Gable Department of Biology Eastern Connecticut State University Willimantic, Connecticut 06226-2295 USA Postilla Published by the PEABODY MUSEUM OF NATURAL HISTORY YALE UNIVERSITY Curatorial Editor-in-Chief Jacques A. Gauthier Executive Editor Lawrence F. 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The genus Maera Postilla Number 221 29 February 2000 (Crustacea: Amphipoda: Melitidae) from Bermuda Sandro Ruffo Traudl Krapp Michael F Gable (Received |8 December | 998; revised and accepted 2 August 1999) Abstract Traditionally, the Bermudian amphipod fauna has included three species of Maera. After examining collections that span more than |0 years, we retain one species, M. tinkerensis; report a second species, M. quadrimana, as a verified record for the Atlantic; and describe four new species: M. ceres, M. miranda, M. ariel and M. caliban. Discussion of M. quadrimana sensu lato, M. pacifica and M. rathbunae clarifies their taxonomic status and their relationship to the Bermudian fauna. Maera tinkerensis resides within the grossimana complex of species, and the other five species reside within the quadrimana complex. The zoogeographical implications of these morphological “complex” alignments are briefly considered. We provide data on habitat preferences and a key to the six species of Maera now recognized from Bermuda. Key Words New species, Maera quadrimana complex, Maera grossimana complex, zoogeography, habitat preferences, taxonomic key. Abbreviations Al,2 antenna |, 2 acc accessory art article Cx coxa EpI—3 epimeral plate |—3 Gnl,2. gnathopod 1,2 Md mandible Mx1!,2 maxilla 1,2 Ov ovigerous P3-7 —_peraeopod 3-7 T telson Ui-3 uropod I-3 BBSR Bermuda Biological Station for Research USNM_ National Museum of Natural History YPM ~~ Peabody Museum of Natural History, Yale University Introduction In his work on the amphipods of Bermuda, Kunkel (1910) cited three species in the genus Maera. The first two, Maera inaequipes (A. Costa 1851) and M. rathbunae Pearse (1908), are of the quad- rimana complex (sensu Barnard 1972, Krapp et al. 1996); the third species, 4 Postilla 221 The Genus Maera (Crustacea: Amphipoda: Melitidae) from Bermuda Figure | Maera quadrimana (Dana), Bermuda. YPM 21601, male: a, Md palp; b, Mx2; c, Gn1; d, Gn2; e, U3; f, T. YPM 21602, ovigerous fernale: g, Gn2. Unattributed immature female (3 mm): h, Gn2 palmar margin. Scale 0.2 mm. The Genus Maera (Crustacea: Amphipoda: Melitidae) from Bermuda Maera tinkerensis Kunkel (1910), was de- scribed as a new species. However, Kunkel’s written descriptions and illustra- tions of these species lack sufficient detail for comparisons. Krapp et al. (1996) questioned the citation of Maera inae- quipes from Bermuda and assumed the presence of a different taxon there. We had similar doubts concerning M. rath- bunae Pearse (1908) because Kunkel’s (1910) illustrations do not correspond with those of Pearse’s (1908) description. From 1985 through 1995, M. F. Gable (Eastern Connecticut State University), E.A. Lazo-Wasem (Peabody Museum of Natural History, Yale University), A. J. Baldinger (Museum of Comparative Zool- ogy, Harvard University) and students from Eastern Connecticut State Univer- sity collected amphipods in Bermuda. The authors have identified or described sev- eral species of Maera from these collec- tions, all belonging to the guadrimana complex, except M. tinkerensis. One is an Indo-Pacific species, M. quadrimana (Dana 1853), already known from other regions; four species are new to science; and M. tinkerensis remains valid. Materials and Methods Specimens were collected in Bermuda over a decade from as many different habitats and microhabitats as possible. Some littoral and shaliow infralittoral specimens were handpicked in the field with forceps either during low tide col- lections on shore or while snorkeling. Other specimens from the same habitats were screened from formalin washes of substrates in the field, or from formalin washes of substrates taken to the labora- tory at the Bermuda Biological Station for Research (BBSR). Sublittoral samples were collected by SCUBA, and specimens Postilla 22 | 5 from these were picked out from forma- lin or 70% EtOH washes at the BBSR. All specimens were deposited at the Peabody Museum of Natural History, Yale University (YPM). Locality data (with YPM locality numbers) for those samples con- taining specimens of Maera are listed in the Appendix. YPM catalog numbers shown below are followed by YPM local- ity numbers. Several lots collected from Bermuda and deposited in the National Museum of Natural History (USNM) were also ex- amined for specimens of Maera. Am- phipods in these lots were coincidentally collected from various expeditions in the 1870s, and in the 1970s to early 1980s. Detailed investigation of entire speci- mens under light- and phase-contrast mi- croscopes was made using alcohol/glyc- erin depression slides. Dissections were done in glycerine and permanent slides were made with Faure’s medium. Systematic Descriptions MAERA QUADRIMANA (DANA 1853) Figures | and 2. Gammarus quadrimanus Dana 1853:955—956, pl. 65, fig. 9. Maera quadrimanus Bate |862:194—195, pl. 35, fig. 5. Maera quadrimana Schellenberg | 938:45—-48, figs. 21-22. Maera quadrimana J. L. Barnard 1965:511—512, fig. 17. Maera quadrimana J. L. Barnard 1970:152—155, figs. 94-95. Maera quadrimana J. L. Barnard |971:84, figs. 31, 38, 40. Maera quadrimana Ledoyer 1982:542-544, fig. 206. Maera quadrimana Berents 1983:128—129, fig. 22. 6 Postilla 22! The Genus Maera (Crustacea: Amphipoda: Melitidae) from Bermuda abcdef — Figure 2 Maera quadrimana (Dana), Bermuda. YPM 21601, male: a—c, PS—7. YPM 21603, immature male (3 mm): d-f, P5—7. Scale 0.2 mm. Maera quadrimana Myers 1985:1 16-117, 14 specimens, | slide; YPM 21562 fig. 91. (IZ.S00196), 3 juveniles; YPM 21600 nec Maera quadrimanus Thomson 1882 (IZ.S00128), | ovigerous female; YPM (not Dana): 235-236, pl. XVII, fig. 4a 21601 (1Z.S00128), | male on 7 slides; (= Maera tepuni J.L. Barnard 1972). YPM 21602 (1Z.S00128), | female on 5 nec Maera quadrimana Ledoyer 1986 (not — slides; YPM 21603 (IZ.SO0128), | imma- Dana):190, fig. 11 (= Maera miranda ture male on 3 slides; USNM 291165, | nobis). specimen, Bermuda, Hungry Bay Rocks, 16 August 1975, collector M. L. Jones. Type locality. Fiji Islands. Description of material from Bermuda. Material examined. YPM 21539 (IZ.S00128), Male: 4.5 mm.A\I slightly shorter than The Genus Maera (Crustacea: Amphipoda: Melitidae) from Bermuda Figure 3 Postilla 22 | 7 Schematic representation of Gn2 palmar margin: paC, Maera pacifica Schellenberg, Cuba; paH, Maera pacifica Schellenberg, Hawaii, syntype; cer, Maera ceres n. sp.; mir, Maera miranda n. sp.; quB, Maera quadrimana (Dana), Bermuda; quF, Maera quadrimana (Dana), Fiji, from Myers 1985. one-half of body, ratio of arts |:2:3 of pe- duncle equals 0.9:1:0.25, art with 4 elon- gate spines and long setae on ventral margin, flagellum with up to |7 articles, acc flagellum longer than one-half flagel- lum, with up to 6 articles. A2 is three- quarters of Al, peduncle robust, with nu- merous long setae, ratio of arts 4:5 equals |.25:1, flagellum very setose with up to 10 articles. Md palp art! distally smooth, art2 to art3 subequal in length, art2 with 8 setae on inner margin, art3 with 7 setae on inner margin and 5 long apical setae. Mx2 outer plate distinctly wider than inner one. Cx! antero-ven- trally rounded, not produced. Gn2 palmar margin of propodus with 2 excavations (Figure 3,a and a’) defining 2 truncate, narrow processes (B’ and B), delimited by a strongly acute prominent process, pre- ceded by a wide semi-elliptical excavation (b); the acute process subdistally provided with | short spine on inner margin; dactylus inner margin smooth (rarely fee- bly inflated medially); outer margin with | seta. P5 basis narrowly ovato-rectangu- lar, with marked postero-distal rounded lobe, posterior margin feebly convex, nearly smooth, without setae. P6—7 basis similar in shape, size in PS