Bryocyclops anninae ( Menzel, 1926 )
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https://doi.org/ 10.26107/RBZ-2019-0016 |
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publication LSID |
lsid:zoobank.org:pub:A3338D70-93CD-41CD-A81D-CDFF4AD964AD |
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persistent identifier |
https://treatment.plazi.org/id/0382F327-FFE8-E05B-FF25-FDB1B3E9FCD3 |
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treatment provided by |
Carolina |
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scientific name |
Bryocyclops anninae ( Menzel, 1926 ) |
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Bryocyclops anninae ( Menzel, 1926)
( Figs. 5 View Fig A–G, 6A–F, 7A–D, F [female]; 7E, 8A–D [male])
Material examined. Three females and three males were collected from a water pool in Thien Duong Cave on 21 March 2012 by L. Sanoamuang; ( Quang Bin Province , Phong Nha-Ke Bang National Park , Quang Bin Province, central Vietnam. Coordinates of the cave entrance were: 17°31′09.46″N, 106°13′17.80″E, altitude: 200 m a.s.l.). One female (total body length 850 µm) and one male (total body length 755 µm) completely dissected, each of them mounted on one slide, NHMUK 2018.1015 (female), NHMUK 2018.1016 (male). Two adult females, two adult males, stored in 70% ethanol, deposited in the Khon Kaen University Science Museum, KKU–COP–2018.005–008 GoogleMaps .
Description. Female ( Figs. 5 View Fig −7): total body length measured from tip of rostrum to posterior margin of caudal rami, 811−850 µm (mean: 830 µm; n = 3), prosome/urosome ratio about 1.9 ( Fig. 5A View Fig ). Preserved specimens colourless, naupliar eye not discernible. Body length/width ratio about 3.2, slightly compressed dorsoventrally. Integument not strongly chitinised, with conspicuous refractile points throughout body surface, without cuticular windows. Cephalothorax about 0.8 times as long as wide, representing 32% of body length, greatest width at posterior end. Posterior margins of Pd1–Pd5 smooth. Genital double-somite well developed, about 0.8 times as long as wide ( Fig. 5A, B View Fig ). Copulatory pore small, oval-shaped, situated at 1/2 length of somite, copulatory duct short, narrow and well sclerotised. Seminal receptacle with well-developed anterior part, representing about 1/4 of double-somite length, posterior part very small ( Fig. 5B View Fig ). Ovipores situated laterally, at 1/2 length of somite, covered by a reduced P6 ( Fig. 5B, C View Fig ). Genital double-somite and two subsequent somites with serrate hyaline fringes with irregular serration both ventrally and dorsally. Anal somite with rows of spinules on posterior margin ventrally. Anal operculum well-developed, triangular, with smooth free margin, reaching 1/2 length of caudal rami, at the base of operculum two large sensilla ( Fig. 5D View Fig ).
Caudal rami ( Fig. 5A, B, D, E View Fig ): parallel, each ramus about twice as long as wide, with low ridge on dorsal side along longitudinal axis. Anterolateral accessory seta (I) reduced. Anterolateral seta (II) bare, inserted at 1/2 length of ramus. Posterolateral seta (III) bipinnate. Outer terminal seta (IV) plumose, with breaking plane; inner terminal seta (V) longest, plumose, with breaking plane, about 0.5 times as long as body length. Terminal accessory seta (VI) stout and bare, very short. Dorsal seta (VII) articulate, bare, inserted near insertion of inner terminal seta (V). Length ratio of caudal setae II–VII to ramus length: 0.8, 1.4, 4.1, 7.4, 0.2 and 1.6, respectively. Length ratio of caudal setae II–VII: 1.0: 1.8: 3.7: 9.5: 0.3: 2.0.
Antennule ( Fig. 6A View Fig ): 11-segmented, nearly reaching posterior margin of cephalothorax, second and third segments partly fused. Setal formula: 6.2.4.2.0+I.2.3.2+ae.2.3.7+ae. Fifth segment with short spine on anterodistal margin. Terminal segment with acrothek subapically.
Antenna ( Fig. 6B View Fig ): 4-segmented, comprising coxobasis and 3-segmented Endp. Coxobasis with one smooth seta on distal inner corner, without seta representing Exp. Endp-1 with group of spinules on outer margin, one smooth seta at 1/2 length of inner margin. Endp-2 about twice as long as wide, with five smooth setae on inner margin (three laterally, two apically; apical setae robust and recurved). Endp-3 twice as long as wide, with seven smooth setae apically.
Labrum ( Fig. 5F View Fig ): trapezoidal, cutting edge strongly chitinised, with two large indentations laterally, concave row of a dozen teeth medially, two rows of spinules ventrally.
Mandible ( Fig. 6C View Fig ): with strongly chitinised gnathobase, cutting edge with pinnate seta dorsally. Mandibular palp completely reduced, represented by one short, bare seta.
Maxillule ( Fig. 6D View Fig ): with robust praecoxa and 2-segmented palp, proximal segment of palp coxobasis, distal one Endp. Arthrite of praecoxa bearing: six armature elements along inner margin, five of them smooth, proximal one robust and pinnate, distal one robust and curved; three claw-like extensions apically; and one curved seta laterally. Coxobasis with proximal seta representing Exp, two setae apically, one slender and one robust, bipinnate, and one slender seta subapically. Endp with two setae apically, equal in length, one shorter seta subapically.
Maxilla ( Fig. 6E View Fig ): 5-segmented. Endite of praecoxa conspicuous, with two plumose setae. Proximal endite of coxa with one smooth seta apically, distal endite elongate, with one unipinnate seta and one smooth seta. Basis with claw-like expansion, with row of spinules along concave margin, two setae at base of claw, longer seta as long as claw, robust, other one short and slim, 0.3 times as long as longer seta. Endp 2-segmented, proximal segment with two robust setae, distal segment with one robust seta apically, accompanied by two slender setae, unequal in length, longer one as long as robust seta, shorter half of it.
Maxilliped ( Fig. 6F View Fig ): 4-segmented, comprised syncoxa, basis and 2-segmented Endp. Syncoxa with two setae, shorter one pinnate, longer one smooth, twice as long as shorter seta, row of few spinules along outer margin. Basis with one bipinnate seta, with row of spinules along inner margin and row of spinules on distal outer margin. Proximal segment of Endp with one strong, pinnate seta. Distal segment armed with 2 smooth setae.
Intercoxal sclerites of P1–P4 (Fig. 7A–D, F): unornamented, free margin of sclerite concave, distal projections rounded in P1 and acute in P2–P4. Coxa rectangular, one cuticular pore present anteriorly, close to medial margin. Long plumose seta present on inner distal corner of P1, coxal seta absent in P2−P4. Basis with medial expansions rounded, long plumose outer seta present on P1, P3 and P4, corresponding seta short and smooth on P2. Exp and Endp 2-segmented. Exp-2 spine and setae formula: 3.3.3.3 and 5.5.5.4. Endp-2 spine and setae formula: 1.1.1.1 and 3.4.5.3. Complete armament of P1–P4 is shown in Table 3.
P 1 (Fig. 7A): Exp-1 small, as long as wide, with one blunt and slightly curved spine. Exp-2 about 1.8 times as long as wide. Endp-2 about 1.3 times as long as wide, apical spine as long as segment, slightly curved and blunt.
P2 (Fig. 7C): Exp-1 small, as long as wide. Exp-2 1.8 times as long as wide, with blunt spines, medial setae with blunt tips. Endp similar to that of P1, but terminal segment with two setae on inner margin, apical spine as long as terminal segment, straight, with sharp tip.
P3 (Fig. 7D): identical to P2 but with three setae on inner margin of Endp-2, apical spine straight, as long as segment bearing it. Setae on Exp without blunt tips.
P4 (Fig. 7F): Exp-2 about 1.8 times as long as wide, similar in shape to P2 and P3 but with relatively weak spines. Endp-1 robust, slightly wider than long, with cuticular expansion on proximal inner corner. Endp-2 rectangular, slightly longer than wide, apical spine slim, as long as segment bearing it.
P5 ( Fig. 5B, C View Fig ): reduced to two cuticular lobes, completely fused to Pd5, both lobes well separated. Dorsal lobe minute, with one slender seta oriented dorsally. Ventral lobe more conspicuous, dorsal seta short and plumose, ventral seta longer, robust and smooth; ventral seta about twice as long as dorsal one.
P6 ( Fig. 5C View Fig ): small, forming simple cuticular plate, inserted laterodorsally on genital double-somite, armed with three elements: anterior seta plumose, middle one shortest, spiniform posterior one longest and slightly longer than anterior one.
Spermatophore ( Fig. 5G View Fig ): paired, kidney-shaped; with thick walls.
Male ( Fig. 8 View Fig ): total body length, measured from tip of rostrum to posterior margin of caudal rami, 713−755 µm (mean: 730 µm; n = 3). Habitus slightly slender than in female ( Fig. 8A View Fig ), body length/width ratio about 3.2, prosome/urosome ratio about 2.1, naupliar eye not discernible. Cephalothorax and Pd2–Pd4 similar to female. Cephalothorax slightly wider than long, representing 33% of body length. Genital somite large, globular ( Fig. 8A, B View Fig ), about 0.3 times as long as whole urosome, including caudal rami. Hyaline structures on dorsal and lateral margin of genital somite well developed ( Fig. 8A, B View Fig ). Subsequent three urosomites distinctly narrower than genital somite, with irregularly serrated hyaline fringes ventrally and laterally. Anal somite and anal operculum as in female ( Fig. 8A View Fig ). Caudal rami ( Fig. 8A View Fig ) similar to that of female.
Antennule ( Fig. 8C View Fig ): 16-segmented, geniculate. Armament formula (however, number of elements on some segments couldn’t be verified): 7+ae.4.2.2+ae.1.3.2.2.0.2.1.1+I.2.1.1. 10+ae. Terminal segment with acrothek.
Antenna, mouthparts, P1, P2, P4 and P5 similar to those in female, but some details variable on P4 (see below).
P3: Exp similar to female. Endp-2 bearing modified apical spine with distal half curved and slightly widened, with finely serrated section, tip acute and hooked. Inner terminal seta of Endp-2 short, spiniform and smooth, half length of modified spine; subterminal inner seta short and also spiniform (Fig. 7E).
P6 ( Fig. 8B View Fig ): modified to large elongated subtrapezoidal plate with three setae laterally, subequal in length, middle one slim and longest, ventral one strong and spiniform, dorsal one slim and shortest.
Variation. In one male, P4 bears additional terminal seta ( Fig. 8E View Fig ). No other variations were observed, except for some minor variations in size, shape, and number of spinules ornamenting any limbs.
Fig. 7. Bryocyclops anninae . A, C, D, F, female. B, E, male. A, P1; B, intercoxal sclerite; C, P2; D, P3; E, Endp of P3; F, P4. Scale bars: A, C–D, F, 100 μm; B, E, 50 μm.
Remarks. The following characters were used for generic identification: i) 11-segmented antennule ( Fig. 6A View Fig ); ii) thoracic legs with 2-segmented rami (Fig. 7A, C, D, F); iii) P5 completely fused with Pd5 ( Fig. 5B, C View Fig ) (baseoendopodal seta inserted on a small laterodorsal lobe, a remnant of the proximal segment of P5, i.e., coxa, basis, and Endp; two setae inserted on ventral lobe, a remnant of the Exp P5); iv) acute prominences of the intercoxal sclerites in P2–P4 (Fig. 7C, D, F); v) absence of coxal seta in P2–P4 (Fig. 7C, D, F); vi) sexual dimorphism on the apical spine on the distal endopodal segment of P3 (Fig. 7D, E); vii) well-developed anal operculum ( Fig. 5D View Fig ); viii) integument ornamented with refractile points ( Figs. 5A View Fig , 8A View Fig ); and, ix) obtuse setae on distal exopodal segment of P2 and P3 (Fig. 7C, D). Based on the unique combination of some characters, such as the remarkably short terminal accessory seta (VI) and the smooth triangular-shaped anal operculum, we identified the Vietnamese specimens as B. anninae ( Menzel, 1926) . This species was originally described from Java, Indonesia, and later recorded from Guam, Hawaii, and Vanuatu ( Menzel, 1926; Lindberg, 1954; Eldredge & Miller, 1997; Reid, 1999).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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