A new genus of aquatic cave-dwelling isopod from Namibia (Crustacea: Isopoda: Asellota) Brian Kensley Depanment of Invenebrate Zoology, National Museum of aroral History, Smithsonian Institution, Washington, D.C. 20560 A new genus Namibianira, represented by four new species, N. aigamasensis, N. dracohalitus, N. arnhemensis, and N. aikabensis is diagnosed. The new genus is intermediate between Protojanira and Protojaniroides and is characterized by the possession of ambulatory first pereopods, and a reduced molar process of the mandible. The new species are the first record of cavernicolous freshwater isopods 'from Namibia. describe them, given that they occupy a taxonomically intriguing position and that A survey of the invertebrate fauna of Namibian stygobiont asellotes were previously unknown caves by Dr. J. Irish and Mr. E. Marais of the from Namibia. State Museum, Windhoek, yielded blind aquatic asellote isopods from four limestone caves in Type material is deposited in the State Museum, central and northern Namibia. Descriptions of Windhoek, amibia (SMN); a few paratypes of two of these caves, Drachenhauchloch (Dragon's N. arnhemensis and N. aikabensis have been Breath Cave) and Aigamas Cave, may be deposited in the National Museum of Natural obtained from Sefton et al. (986). The former History, Smithsonian Institution, Washington, contains an under-ground lake over 200 m long D.C. (USNM). and up to 150 m wide, and not less than 40 m SYSTEMATICS deep. The water of Aigamas Cave contains a species of blind fish, Clarias cavernicola. SUPERFAMILY GNATHOSTENETROIDOIDEA Arnhem Cave, the longest yet known in Namibia, Kussakin, 1967 contains five pools all about 5 x 8 m in extent, FAMILY PROTOJANIRIDAE Fresi, Idato, & and less than 1 m deep, inhabited by amongst Scipione, 1980 others, ingolfiellid amphipods (T. Irish, pers. comm.). The Aikab Hemicenote contains a Namibianira gen. novo roughly circular lake with direct surface access. DIAG OSIS: Eyes lacking. Cephalon with rostral This underground lake has a diameter of about projection barely discernible. Antennal peduncle 100m, and a minimum depth of 19m (E. M~r~is; with 4 basal anicles short, article 3 bearing scale. pers. comm.). Mandibular palp of 3 anicles; molar thin-walled, While superficially similar, the isopods in the conical, bearing 2-3 apical setae. Maxillipedal four lots did differ in size; further additional endite bearing 2 coupling hooks, palp articles subtle differences were found, suggesting that 1-3 broad, articles 4-5 slender. Pereopod 1 four separate species were involved. Even ambulatory, dactylus biunguiculate, not folding though all the specimens had lost their antennal on propodus. Pereopods 2-7 ambulatory, dactyli flagella and uropods, most had lost some or all triunguiculate. Pleopod 1 in male with rami of their legs, and males were present in only lamellar, basally fused, lacking sperm tube. Pleo- two of the lots, it was decided to name and pod 2 in male, exopod lobe-like, of 2 articles, endopod distally tapered and stylet-like with ambulatory pereopod 1 and a stout distally trun- tube opening at apex, not reaching apex of cate mandibular molar. Protojaniroides pos- protopod. Pleopod 2 of female broad, opercular, sesses a strongly sub chelate pereopod 1 and a bearing marginal setae, and with roughly circu- thin-walled conical mandibular molar. Other lar central denser area. Pleopod 3 biramous, rami than in Protojanira lucei Enckell, 1970, none of biarticulate. Pleopod 4 and 5 uniramous, rami the species of these two genera have been des- biarticulate. One short free pleonite. cribed as possessing a free pleonite, but this is probably an oversight, given the difficulty in TYPE SPECIES: By present designation, seeing this very short segment. The present ge- Namibianira arnhemensis sp. novo nus appears to occupy an intermediate posi- ETYMOLOGY: The generic name is derived from tion, in that it resembles Protojanira in having the state of Namibia, plus the Latin suffix '-ianira', an ambulatory pereopod 1, and Protojaniroides indicating its asellotan affinity. in the form of the mandibular molar; it clearly possesses a short, free pleonite. DISCUSSION: Two protojanirid genera have been diagnosed from southern Africa, viz. Namibianira aigamasensis sp. novo Protojanira Barnard, 1927, and Protojaniroides Fresi, Idato, and Scipione, 1980 (Table 1). The Figures 1, 2 species of these genera are morphologically all MATERIAL:Holotype, SMN 51603, 9 tl 3.6 mm, very similar; two characters have been found to Paratypes, SMN 51257, 3 9 tl 3.0 - 3.6 mm, be of importance in distinguishing them: Aigamas Cave, 3-8 m, Otavi District, coil. A. 1. Pereopod 1, which is primitively ambulatory, Penney, 27 Jul 1987. and resembles the remaining pereopods. The DESCRIPTION: Body about 3.7 times longer than apomorphic state ofthis character is a subchelate greatest width, widest at pereonite 3; with spar- pereopod 1, with the propodus somewhat ex- sely scattered setae on cephalon, pereon, and panded. pleon. Cephalon about one-fourth wider than 2. The mandibular molar process, which primi- mid-length; anterior margin with low convex tively is stout and distally truncate with a grind- rostral area. Pereonites 1 and 2 subequal in ing surface, and thin-walled, tapered, and lack- length; pereonites 1-3 increasing in width ing a grinding surface in the apomorphic state. posteriorly, anterolaterally rounded, broadening Protojanira is characterized by possessing an posteriorly; pereonites 4-6 subequal in Width; Aigamas Cave, Otavi District, Namibia. Aikab Hemicenote, Etosha National Park, Namibia Dragon's Dreath Cave, Grootfontein District, Namibia. Protojanira leleupi Grindley, 1963. Kalk Bay Mountains, Cape Peninsula, South Africa. Protojanira prenticei Barnard, 1927. Kogelberg, Honentots Holland Mountains, Cape Province, South Africa. Protojaniroidesjicki (Chappius & Delamare, 1957). Kaapsehoop, Eastern Transvaal, South Africa. Protojaniroides lucei (Enckell, 1970). North-central Sri Lanka. Protojaniroides perbrincki (Barnard, 1955). Figure 1. Namibianira aigamasensis. A, whole animal, dorsal view, antennae and uropods lacking, scale = 0.5 mm; B, antennule; C, right mandible; D, mandibular palp; E, left mandible; F, antennal scale; G, maxilla 1; H, maxilla 2; I, maxilliped with epipod. Figure 2. Namibianira aigamasensis. A, pereopod 1; B, pereopod 7; C, 9 pleopod 2 operculum; D, pleopod 3; E, pleopod 4; F, pleopod 5. pereonite 7 slightly narrower than preceding rior submedian setae); with centrally located, somites; pereonites 5-7 laterally broadly relatively small, ovoid, denser area. Pleopod 3 rounded, posteriorly directed, increasing in endopod of 2 articles, basal article rectangular, length posteriorly. Pleon consisting of single distal article shorter and narrower, roughly ovate; dorsally-free short anterior pleonite plus exopod of 2 articles articulating obliquely, distal pleotelson; pleonite overlapped laterally by article broadly rounded, with circular posterolateral lobes of pereonite 7. Pleotelson proximomesial area. Pleopods 4 and 5 roughly rectangular, wider than mid-length, uniramous, with broad basal article and shorter posterior margin with 2 faint submedian con- and narrower distal article, pleopod 5 slightly vexities. shorter than 5. Antennule with broad basal article wider and ETYMOLOGY: The specific epithet is derived longer than article 2, latter twice longer than from the type locality, Aigamas Cave. wide, article 3 about half length of 2; flagellum Namibianira dracohalitus sp. novo of 7-12 articles, distal 4-6 articles each bearing single aesthetasc. Antenna having 4 short basal Figures 3, 4 articles, article 3 bearing strong lateral scale, latter MATERIAL:Holotype SMN 51605, 9 tl 5.0 mm, with 2 distal setae. Mandibular incisor having 7 Paratypes, SMN 51260, 39 tl 5.0 mm, Dragon's cusps; left mandible having lacinia mobilis with Breath Cave, 32 - 38 m, Grootfontein District, 7 or 8 teeth plus spine row of 4 fringed spines, coil. P. Church, 22 Jul 1987. right mandible with spine row of 5 or 6 fringed DESCRIPTION: Body about 3 times longer than spines; molar process thin-walled, tapering, with wide, widest at pereonites 6 and 7. Integument single short seta and 2 elongate fringed setae with scattered setae, especially along lateral distally; palp of 3 articles, article 2 1.3 times margins of pereonites and pleon. Cephalon one- length of article 1, with 5 distolateral bifringed fourth wider than mid-length, anterior margin spines, first and last in series larger; article 3 with very faint rostral convexity. Pereonites 1-4 with row of 9 or 10 spines increasing in length with anterolateral rounded margin becoming distally. Maxilla 1, mesial lobe with 5 distal setae; wider posteriorly. Pereonites 5-7 with postero- lateral lobe almost twice width of mesial, with lateral areas slightly produced posteriorly. Pereo- double row of about 13 curved pectinate spines. nite 7 longest. Single free pleonite short, over- Maxilla 2 with 2 lateral lobes each bearing 4 lapped laterally by lobes of pereonite 7. Pleotel- elongate pectinate setae; mesial lobe with sev- son slightly wider than mid-length, posterior eral simple setae on mesial and distal margin. margin with 2 faint submedian convexities. Maxillipedal epipod length about 2.5 times width, distally rounded; endite with 2 coupling Antennular flagellum of 12-15 articles, 8 distal hooks on mesial margin, 3 rows of subdistal articles each bearing single aesthetasc. Four basal setae, middle row consisting of 6 broad fringed