Grimaldina brazzai Richard 1892
Creators: name: Neretina, Anna N.
name: Kotov, Alexey A.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Branchiopoda
Diplostraca
Macrothricidae
Grimaldina
Grimaldina brazzai

description: Grimaldina brazzai Richard, 1892
(Figs. 1–7)
Grimaldina brazzai Richard 1892: p. 214–218, figs. 1–3.
? Grimaldina brazzai Richard in Daday 1910: p. 138–139, Pl. 7: fig. 26; Rahm 1956: p. 248–250, fig. 7; Rey & Saint-Jean 1968: p. 97, fig. 13 (a–d); Idris 1983: p. 39, figs. 18a–b; Kořínek 1984: p. 50, pl. 26: figs, 2–7; Venkataraman 1990: p. 166, fig. 1; Silva-Briano 1998: p. 149–151, figs. 1–8).
Type locality. “ Mayoumba et Caca Muerca (Congo Français)” (Richard, 1892), now in Gabon (Central Africa).
Type material. The type material is available at the collection of the National Museum of Natural History, U.S.A. (Kotov & Ferrari 2010). A lectotype was selected by Kotov and Ferrari (2010): “ USNM 1134577: Parthenogenetic female on slide with Richard number 207 labeled “ Grimaldina brazzai Richard, ♀, Congo, Caca Muerca, 10 juin 1890 ”. For analysis of other Richard’s material with Grimaldina see comments in Kotov and Ferrari (2010).
Other material examined. Ethiopia (East Africa): 4 formaldehyde-fixed parthenogenetic females from a swampy grassland connected with Lake Tana, near the Bahir-Dar Fishery and Other Aquatic Life Research Center (N 11.61586°, E 37.37708°), coll. in 22/02/2009 by A.A. Kotov, AAK 2009-130; 2 formaldehyde-fixed parthenogenetic females from a swampy grassland connected with Lake Tana (N 11.61405°, E 37.37597°), coll. in 17/10/2015 by A.N. Neretina, ANN 2015 -019; 1 ethanol-fixed parthenogenetic female from a swampy grassland connected with Lake Tana (N 11.61405°, E 37.37597°), coll. in 17/10/2015 by A.N. Neretina, ANN M-0028.
Thailand (South East Asia): 1 formaldehyde-fixed parthenogenetic female from the channel in Phathum Thani Province, coll. in 24/10/1994 by J. Wongsanoon, AAK 1998-020; 1 formaldehyde-fixed parthenogenetic female from Canal in Muang District, Phitsanulok Province, coll. in 29/09/1996 by L. Sanoamuang, AAK 2003-065; 10 formaldehyde-fixed parthenogenetic females from the paddy field, near Phitsanulok, foodplain of the River Nan, Phitsanulok Province, coll. in 27/09/1996 by L. Sanoamuang, AAK 2004-050; 15 formaldehyde-fixed parthenogenetic females from Kaeng Lawa Lake (N 55.75°, E 37.62°), coll. in 30/01/2016 by A.Y. Sinev, AYS TL- 18.
Redescription. Parthenogenetic female. General. In lateral view, body subrectangular, maximum height at middle of body (body height/length ratio about 0.7 for adults) (Figs. 1 A, 2A). In dorsal view body moderately compressed laterally, without an expressed dorsal keel. In anterior view, body elongated. Dorsal margin regularly arched in anterior portion and almost straight in its posterior part; a depression between head and valves absent. Posterodorsal angle expressed, posteroventral angle rounded. Anteroventral angle broadly rounded. Valves with prominent sculpture, consisting of elongated scales (Fig. 2 A–F).
Head relatively large, not keeled, triangular in lateral view, with convex dorsal margin and strongly concave ventral margin (Figs 1 B, 2B–C). Ventral surface of head with a protuberance near bases of antenna I (Fig. 2 B–C). Eye about two times larger than ocellus. Distance from anteroventral head extremity to center of ocellus four times shorter than distance between center of ocellus to center of eye. A single frontal head pore located between bases of antennae I (Fig. 2 D: arrow). Major and lateral dorsal head pores absent (Fig. 2 E). Labrum large, subquadrangular, with apex hirsute and a massive setulated distal labral plate (Fig. 1 C).
Valve. Ventral margin slightly convex, with exactly marginal setulated setae organized in groups of three setae decreasing in size posteriorly in each group; setae in these groups slightly longer in region of posteroventral angle (Figs. 1 D–G, 3A–B). Inner side of posteroventral portion with short setulated setae, almost subequal in size (Fig. 1 H). A row of small stiff setulae on the inner side of valve at posterior margin, they increasing in size from posterodorsal angle to posteroventral angle (Fig. 1 I).
Thorax long, abdomen relatively short.
Postabdomen large, semicircular, strongly compressed laterally (Fig. 1 J). Postabdomen length/height ratio about 2. Ventral margin almost straight or slightly convex. Preanal margin long, curved, subdivided into two lobes: distalmost one approximately two times longer than proximal one (Fig. 1 K). Preanal margin about four times longer than anal margin; anal and postanal margins almost equal in length. Preanal and postanal angles smooth. Basis of claws slightly inflated (Fig. 1 L). Preanal margin with minute teeth, forming small groups distally. Armature of anal margin as groups of fine setulae, plus a single setulated seta located proximally; also a bunch of 5–6 setulated setae laterally. Postanal margin with a row of 6–7 setulated setae, among them the distalmost setae shorter than others, and fine groups of setulae above them (Fig. 1 L). At claw base at least two groups of small denticles and a single denticle between them. Postabdominal setae longer than postabdomen, with distal segment half of the length of the basal segment. Distal segment bears long setules. Postabdominal claw relatively robust, long (subequal in length to anal margin of postabdomen) (Figs. 1 L–N, 3C). External dorsal side armed in its proximal portion by a row of fine teeth, decreasing in size distally. Internal side of claw with a row of teeth, they specially long in proximal portion, and decreasing in size distally. Relatively robust teeth on ventral side of claw. At the base of claw, a relatively long basal spine (about two times longer than diameter of claw base) and a small denticle located proximally.
Antenna I long, thin, “rod like” in terms of Smirnov (1992) (Figs. 3 D, 4A). Antennular sensory seta slender, arising at about 1/4 of its length from base. A row of small spinulae along posterior margin, decreasing in size distally. Antennular body covered by rows of fine denticles. Nine aesthetascs, two of them slightly longer than others.
Antenna II long (Figs 3 E, 4B). Antennal formula: setae 0-0-1-3/1-1-3, spines 0-1-0-1/0-0-1. Two sensory setae unequal in size at coxal part; basal segment cylindrical, with circular rows of minute setulae, bearing a small spine (almost subequal in length to basal exopod segment) at its anterior face and a bisegmented setulated seta (slightly longer than basal endopod segment) at its posterior face; all branch segments elongated, with concentric rows of small setulae. Exopod longer than endopod. Apical setae of moderate length (shorter than antennal branches plus basal segment), covered by long and fine spinulae (Figs 3 F, 4B). The largest seta of antenna II (on proximal endopod segment) asymmetrically armed by short setulae along one side (on proximal and distal portions) and more robust spinulae along other side (they cover distal portions and only slightly go to proximal part) (Fig. 4 C– D). Distance between bases of spinulae about four times longer than diameter of this seta (as a result, spinulae on the longest endopod seta of antenna II located relatively sparse). Seta on middle endopod segment long, reaching tips of apical setae, covered by long setules and fine spinulae. Lateral seta of third exopod segment has the same armature. Spine on second exopod segment thin, about three times shorter than third exopod segment (Fig. 4 B). Spines of both apical segments thin, exopod apical spine slightly longer than endopod spine.
Thoracic limbs: five pairs.
Limb I large (Fig. 5 A–B). Accessory seta not found. ODL conical and large, bearing a single long bisegmented seta, its distal segment feathered unilaterally; IDL with three setae, different in length: the longest seta with fine setulae on its distal segment; middle and short setae with somewhat longer denticles in central and distal portions (Fig. 5 B). Several groups of stout setulae on IDL outer face, distalmost groups could be homologized with those on IDL of Eurycercus, see Bekker et al. 2012; Bekker & Kotov 2016; or Leydigia, see Kotov 2009). Limb corm almost rectangular in lateral view. Endite 4 with three posterior soft setae (among them seta “a” the longest with long fine setulae on its distal segment) and a single stiff anterior seta 1 (Fig. 5 A). Endite 3 with three soft posterior setae unequal in size (among them seta “d” the longest, bearing fine setules, setae “e” and “f” armed unilaterally by rough setulae in their distal portions) and a single stiff anterior seta 2 (slightly longer than seta 1 of endite 4). Endite 2 with four posterior soft setae (setae “g–i” long, subequal in size, seta “j” significantly shorter) and a single stiff anterior seta 3 (about two times shorter than seta 2 of endite 3). All three stiff anterior setae with setulated distal segments. Endite 1 (= maxillar process, reminder of gnathobase I) with two soft setulated setae, unequal in size. Rows of fine setulae on ventral face of limb I. Two ejector hooks small, subequal in size.
Limb II triangular-rounded (Fig. 5 C). Exopodite large, ovoid, elongated, covered distally by minute setulae, without setae. Inner portion of limb II with eight scrapers (Fig. 5 C: 1–8), among them setae 1 and 2 longest, setae 3–5 somewhat shorter, and setae 6–8 short. All these setae unilaterally covered by stiff fine denticles in their distal portion. A fork-like projection with bulbous base near scraper 3. A long, bisegmented sensillum (Fig. 5 C: sen) and a soft setulated seta locate near scraper 4. Also, a soft setulated seta near scraper 8. A shallow incision between endite 2 and endite 1 (=gnathobase). Distal armature of gnathobase with four setae (Fig. 5 D: 1–4). Filter plate with six bisegmented setae, three distal setae short, and other three longer.
Limb III with large ovoid epipodite (Fig. 5 E: epp), preepipodite not found. Exopodite subrectangular, with two bilaterally setulated lateral setae unequal in size (Fig. 5 E: 5–6); and four distal setae (Fig. 5 E: 1–4): setae 3–4 short, the longest seta 2 and seta 1 feathered by short setulae in distal portions and long setulae in proximal portions. Endite 5 bearing a stiff anterior seta 1 and a long posterior seta “a” (Fig. 5 F). Endite 4 with a stiff seta 2 and a soft seta “b”. Endite 3 with a stiff seta 3 (a small sensillum near base of this seta) and two soft setae: “c” and “d”. Proximal endite (in terms of Kotov 2013) with four anterior setae (4, 5, 6, 7, a minute sensillum near base of seta 4) and four posterior setae (e, f, g, h). Distal armature of gnathobase with a thick sensillum (Fig. 5 G: 1), two grouped sensillae (3, 4) and a single large densely setulated seta (2). Filter plate with seven bilaterally setulated setae subequal in size.
Limb IV with a large ovoid epipodite (Fig. 6 A: epp), preepipodite not studied. Exopodite rounded, with two long lateral setae (3–4) and two short distal setae (1–2) unequal in size. Inner distal portion with four anterior setae (Fig. 6 B: 1–4) and a very large sensillum near seta 3. Posterior face with five soft setae (a–e). Distal armature of gnathobase consisting of four elements: bottle-shaped thick sensillum, bisegmented seta and two small projections. Filter plate with 6 bilaterally setulated setae increasing in size proximally.
Limb V with a rounded setulated preepipodite (Fig. 6 C: pep) and ovoid epipodite (epp). Exopodite rounded, with a single long seta asymmetrically covered by rows of long and short setulae. Inner distal portion as a setulated lobe, on its inner margin three setae significantly decreasing in size distally: the longest seta clearly bisegmented (Fig. 6 D: 1), proximal segment densely covered by fine setulae, distal segment with more widely spaced thick setules; two other setae (Fig. 6 D–E: 2–3) densely setulated, middle seta about four times longer than shortest seta (thus the proximalmost seta is relatively short). Filter plate was not found, although at least three protuberances were distinguishable.
Ephippial females and males. No ephippial females and males were present in investigated samples. Some information on morphology of African gamogenetic females and males could be found in Kořínek (1984).
Size. Maximum length of adult parthenogenetic females up to 0.69 mm; height 0.47 mm.
Variability. No significant variability between investigated specimens from Ethiopia was found, as well as their differences from Asian populations (Fig. 7 A–F). Several Thai individuals (from a single sample AYS TL-18) had the abnormal short seta on the basal endopod segment (not reaching the tips of apical setae), herewith distance between spinules corresponded well with description (see above).
Distribution. Probably, G. brazzai is distributed from Africa through tropical Asia, although we have been unable to confirm its presence in South Asia. Australian populations (Smirnov & Timms 1983; Smirnov 1995) must be carefully examined in the future, but there is a high probability, that they belong to G. brazzai s. str.
The taxon is rare, some records of G. brazzai are made from Africa (Richard 1892; Daday 1900; Thomas 1961; Rey & Saint-Jean 1968; Dumont 1981; 1986a; b; Green 1962; 1971; 1984; Kořínek 1984; Silva-Briano 1998; Chiambeng & Dumont 2005), South Asia (Fernando 1980; Rajapaksa & Fernando 1982; Rane 1984; Venkataraman 1990; Raghunathan & Suresh Kumar 2002; Chatterjee et al. 2013) and South East Asia (Idris & Fernando 1981; Maiphae et al. 2008; Kotov et al. 2013; Korovchinsky 2013; Sinev & Korovchinsky 2013; Van Damme et al. 2013; Sinev & Yusoff 2015), but only few of them (after Richard 1892) were figured and described (Daday 1910; Rahm 1956; Rey & Saint-Jean 1968; Idris 1983; Kořínek 1984; Venkataraman 1990; Silva-Briano 1998). But, unfortunately, all these descriptions and figures lack diagnostic information, such as: armature of the longest endopod seta and ratio of setae on thoracic limb V: these fine, but important details were not even described by Smirnov (1976; 1992) or Silva-Briano (1998).
description: Published as part of Neretina, Anna N. & Kotov, Alexey A., 2017, Old World-New World differentiation of so-called " circumtropical " taxa: the case of rare genus Grimaldina Richard, 1892 (Branchiopoda: Cladocera: Macrothricidae), pp. 295-323 in Zootaxa 4291 (2) on pages 298-307, DOI: 10.11646/zootaxa.4291.2.4, http://zenodo.org/record/829579