Ilyocryptus cuneatus brasiliensis, Kotov & Elmoor-Loureiro, 2008
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publication ID |
https://doi.org/ 10.11646/zootaxa.1962.1.3 |
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persistent identifier |
https://treatment.plazi.org/id/1B7387DD-9003-5667-9982-D566FCB56921 |
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treatment provided by |
Felipe |
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scientific name |
Ilyocryptus cuneatus brasiliensis |
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subsp. nov. |
Ilyocryptus cuneatus brasiliensis View in CoL subsp. nov.
Figures 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3
Etymology. This subspecies is named after the country where it was found, Brazil.
Type locality. Itaici - lagoa do pesqueiro (23°06'48.2"S, 47°11'03.0"W), Municipio de Indaiatuba , São Paulo, Brazil. It is a small lake bordered by Eichhornia . The type series was collected on 14.xi.2002 by L.M.A. Elmoor-Loureiro GoogleMaps .
Type material. Holotype. An adult parthenogenetic female, MZUSP18854 View Materials . The label of holotype is: " Ilyocryptus cuneatus brasiliensis subsp. nov., 1 parth. ♀ from Itaici - lagoa do pesqueiro, Indaiatuba, SP, Brazil, HOLOTYPE " . Paratypes. 5 parthenogenetic females, MZUSP 18855 View Materials ; 5 parthenogenetic females, MNRJ 21506 View Materials ; 5 parthenogenetic females, EL01603 ; 5 parthenogenetic females, MGU Ml 75; 5 parthenogenetic females, AAK 2008-053 .
Other material studied. A parthenogenetic female, from Ponte Nova reservoir (appr. 23°34'S, 45°58'W), Município de Biritiba Mirim , São Paulo, Brazil, collected on 02.xii.1997, by M.J.C. Botelho GoogleMaps .
Short description. Adult parthenogenetic female. General: In lateral view body subovoid, of medium height for the genus (body height/body length = 0.76–0.81 in adults), maximum height in posterior half ( Figure 1A–B View FIGURE 1 ). Dorsal margin slightly convex to almost straight, postero-dorsal angle distinct. In anterior view,
body rhomboid-rounded, thick, with a low and thick dorsal keel ( Figure 1C View FIGURE 1 ). Moulting incomplete, reticulation on head shield and valves very fine and obscure.
Head small, its ventral margin in posterior part with prominent basis for antennae I, labrum base surrounded with a low fold ( Figure 1D View FIGURE 1 ). In ventral view, head shield triangular-ovoid, with prominent fornices, without a postero-lateral projection in region of process of mandibular articulation, the latter small ( Figure 1E View FIGURE 1 ). Dorsal head pore located on a low prominence ( Figure 1A View FIGURE 1 , D-E, arrow). Compound eye of common size for genus, ocellus small, irregular in shape.
Labrum subquadrangular in lateral view, with a small medial projection in its basal portion and a prominent distal labral plate ( Figure 1D View FIGURE 1 ). In ventral view, labrum body wide, with distinct paired projections in medial portion and levelled paired projections (supplied with two series of fine setules) in its distal portion ( Figure 1F–G View FIGURE 1 ).
Valves subovoid. Numerous setae along free margin ( Figure 1H View FIGURE 1 ), five spaced, relatively short anteriormost setae, followed with a bunch of 4–5 closely located setae, which are just somewhat longer that following setae, the first seta in the bunch directed posteriorly ( Figure 1I View FIGURE 1 ). Setae in middle of ventral margin with long setules, setae in postero-ventral region not longer that the former. Each seta at posterior margin along one side basally with series of spine-like setules, and distally with fine setules ( Figure 1J–K View FIGURE 1 ).
Abdomen dorsally with cross rows of setules ( Figure 2A–C View FIGURE 2 ), a projection of size moderate for the genus on the first (basalmost) segment.
Postabdomen relatively short, height maximal in the middle. Preanal margin somewhat longer than postanal one, with a row of regularly located, straight teeth, which are predominantly doubled. Few denticles near some of preanal teeth. Few denticles on lateral sides of postabdomen basally, or they completely absent. Anus small ( Figure 2D View FIGURE 2 ), 5–6 spinules on its internal wall ( Figure 2E View FIGURE 2 ). A row of relatively short paired spines starts on anal margin and continues up to distal boundary of preanal margin ( Figure 2D View FIGURE 2 ). About seven large lateral setae longer than paired spines, the proximalmost lateral seta smaller, located on distalmost portion of preanal margin. On the distal part of postabdomen, the row of lateral setae fluently transits into a group of 4–5 middlesized setae, the latter, more distally, - into a group of rudimentary setae ( Figure 2F View FIGURE 2 ).
Postabdominal claw slightly bent ( Figure 2F View FIGURE 2 ). There are three pectens of setules along concave dorsal margin. A single denticle on claw ventrally. Two spines of subequal size on the base of each claw dorsally. Long setules on claw base ventrally.
Postabdominal seta longer than postabdomen, its basal segment approximately as long as distal one, the latter with short, sparse hairs ( Figure 2G View FIGURE 2 ).
Antenna I of medium length for Ilyocryptus , relatively thin. Bases of antennae I not compressed against each other ( Figure 1F View FIGURE 1 ). Proximal segment with a well-expressed finger-like projection and low hillocks; distal segment without ridges and denticles ( Figure 2H–I View FIGURE 2 ). Nine relatively short aesthetascs, two of them longer than the rest.
Antenna II relatively short, coxal part with numerous relatively long setules, and two sensory setae of greatly differing size ( Figure 3A–B View FIGURE 3 ). Distal sensory seta on basal segment long, slender, distal burrowing spine shorter than distal sensory seta, setulated distally. Antennal branches massive, on all segments, there are well-developed denticles around distal segment ends, and groups of similar denticles in middle part ( Figure 3C–D View FIGURE 3 ). Swimming setae 0-0-0-3/1-1-3, spines 0-1-0-1/0-0-1. Apical swimming setae relatively short, bisegmented, differing in size, distal segments without hooks on tips, asymmetrically armed with minute setules ( Figure 3E View FIGURE 3 ). Proximal lateral swimming setae shorter than distal one, both armed along one side with setules remarkably longer than those on apical setae ( Figure 3F–G View FIGURE 3 ). Apical spine on exopod longer than spine on endopod. Spine on second segment of exopod about half of third segment length ( Figure 3C View FIGURE 3 ).
Limbs. Of armature typical of the genus. A large seta on outer distal lobe of limb I with basal segment armed unilaterally with sparse setules, and distal segment armed bilaterally with dense setules; a large, bisegmented, naked seta near ejector hooks, a gnathobase I as a naked lobe ( Figure 3H View FIGURE 3 ). Limb VI as a trapeziumshaped plate with inner margin bearing continuous row of setules, separated by small incisions into six series, outer margin with series of setules ( Figure 3I–K View FIGURE 3 ).
Ephippial female, male. Unknown.
Size. Parthenogenetic females from type locality 0.37–0.58 mm, holotype 0.55 mm.
Distribution. At this moment, the taxon is known only from the type locality.
Differential diagnosis. Ilyocryptus cuneatus brasiliensis subsp. nov. differs from the nominotypycal subspecies in: (1) smaller size, up to 0.58 mm; (2) presence of few additional small denticles near preanal teeth; (3) reduced system of denticles on lateral faces of postabdomen; (4) fewer number of setules in bunch in middle portion of inner margin of limb VI.
Comments. I. cuneatus cuneatus is the most common Palaearctic species, rarely occurring in the Nearctic zone ( Kotov et al. 2002b; Kotov & Štifter 2006). Previously cuneatus -like forms were never described from any South of Central American countries. Here we demonstrate that two studied Neotropical populations belong to a separate taxon, although apparently closely related with Holarctic I. cuneatus cuneatus . Some differences revealed above are evidence of an aborigine status of this Brazilian population instead of an introduction from Holarctic due to a human activity.
Some cuneatus -like populations are present in China, South Africa, Australia and new Zealand, but these forms must be revised in the future ( Kotov & Štifter 2006).
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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