Coronatella anemae, Van Damme & Dumont, 2008

Damme, Kay Van & Dumont, Henri J., 2008, Further division of Alona Baird, 1843: separation and position of Coronatella Dybowski & Grochowski and Ovalona gen. n. (Crustacea: Cladocera), Zootaxa 1960 (1), pp. 1-44 : 16-24

publication ID	https://doi.org/ 10.11646/zootaxa.1960.1.1
persistent identifier	https://treatment.plazi.org/id/B34587DE-9020-CD69-56F2-FF42FE8BF868
treatment provided by	Felipe
scientific name	Coronatella anemae
status	sp. nov.

Treatment

Coronatella anemae View in CoL sp. n.

Figs 5–10 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10

Lynceus bukobensis (Weltner) in Ekman (1904)

Alona novae-zealandiae Sars in Jenkin (1934) and Rey & St-Jean (1969)

Alona poppei Richard View in CoL in Delachaux (1917)

Alona rectangula Sars in Dumont et al. (1984)

Type locality. Canyon of Ghor Arbaat; series of samples in isolated rockpools with or without littoral fringe of Typha angustifolia , Red Sea Hills, near Port Sudan, Sudan. Note: we chose Sudan as type locality because Ekman (1904) was the first to find it here (identified as Lynceus bukobensis ; Fig. 5 View FIGURE 5 in Ekman 1904; see Discussion). For more details on locality and a map, see Dumont et al. (1984).

Material examined. Type series. Holotype. One adult parthenogenetic female mounted in glass slide labelled “ Coronatella anemae holotype ”; from type locality; 20.XII. 1981, Leg. H.J. Dumont; Paratypes. One adult parthenogenetic female and one adult male, slide labeled “ Coronatella anemae paratypes ” same slide and data as holotype. Additional paratypes: tube containing mix of females, ephippia and males from type locality. All material deposited at the Royal Belgian Institute for Natural Sciences , Brussels ( RBIN) under accession number IG 30.556 .

Additional material. Material at UG Zooplankton Collection , Ghent University , Dpt. of Biology , Limnology Research Group. Sudan, 30 parthenogenetic females, 5 males, Canyon of Ghor Arbaat ; Red Sea Hills, near Port Sudan, 20.XII.1981 , Coll. H.J. Dumont ( Samples “ Sudan 18”,“21” in UGent Collection). Socotra Island ( Yemen), 50 parthenogenetic females from Qaysoh, permanent wetland South of Qalaansiyah (E- Socotra), K. Van Damme, 17.I.2000 ; 20 parthenogenetic females from Noged , small rock pools at entrance of Noged Cave (SE-Socotra), K. Van Damme, 20.I.2000 ; 60 parthenogenetic females, 20 males from Rewgid , culture from dried mud, series of rock pools in karstic limestone (NC-Socotra), details of habitat in Van Damme et al. (2004). 15 Parthenogenetic females, small pond at entrance of administration building at Sharjah Breeding Centre, Sharjah, United Arab Emirates, Coll. K. Van Damme, 20. VI.2006. 45 parthenogenetic females from Aldabra Island , Seychelles, Coll. K.G. McKenzie, ref. 1969.6.9.566–581 (Natural History Museum, London), 16 tubes. Uzbekistan, 3 parthenogenetic females. Mayalo Ricefield, Coll. I. Mirabdullaev, VIII.2000 .

Etymology. “anemae”, from “anema” (Lat. = wind), indicating dispersal by wind (noted on Socotra Island; See Distribution).

Description of the adult parthenogenetic female. Habitus ( Figs 5A–B View FIGURE 5 & 6 View FIGURE 6 ). Medium-sized animals, 0.4–0.6mm, colourless and transparent. Specimens from Sudan ( Fig. 5B View FIGURE 5 ) are relatively smaller (0.4–0.55mm) than from Socotra Island (0.45–0.6mm) ( Figs 5B View FIGURE 5 & 6 View FIGURE 6 ). In lateral view carapace rectangular with evenly curved dorsal margin and low posterodorsal angle. Ventral carapace margin rather straight in anterior half to slightly concave in posterior half ( Figs 5B View FIGURE 5 , 6A View FIGURE 6 ). Posteroventral corner with notch not well pronounced, close to posteroventral corner ( Fig. 5J View FIGURE 5 ). In dorsal and ventral view, body relatively compressed ( Fig. 6D View FIGURE 6 ) lacking a pronounced keel ( Fig 6B View FIGURE 6 ). Head. Ocellus as large as eye ( Fig. 5A View FIGURE 5 ). Head shield broad with rounded smooth posterior margin ( Figs 5D View FIGURE 5 , 7A View FIGURE 7 ). Rostrum blunt and short, aesthetascs projecting beyond its tip ( Fig. 5D View FIGURE 5 ). Three main head pores ( Figs 6B View FIGURE 6 , 7A View FIGURE 7 ) of same size, narrowly connected, PP distance same as IP distance ( Fig. 7A View FIGURE 7 ); main pores variable, overall relatively small with narrow connection, but broad in population from Rewgid, Socotra, Fig. 8H View FIGURE 8 ; small pores closer to main pores than to lateral margin of head shield, at about 1.5 IP from the midline. In dorsal view, main head pores not elevated, but lateral pores in clear lateral depressions ( Figs 6A–C View FIGURE 6 , 7A View FIGURE 7 ). Strong variability in head pore size between three Socotran populations, from broad to narrow ( Fig. 8 View FIGURE 8 ). Carapace ( Figs 5A–B View FIGURE 5 , 6A–D View FIGURE 6 ). Ornamentation consisting of parallel, well-developed wide striation, no fine striation; number of lines 18–20 ( Figs 5A–B View FIGURE 5 , 6A–D View FIGURE 6 ). Posterior margin wavy. This ornamentation also present on the head shield ( Fig. 6B View FIGURE 6 ). Marginal setae in different groups, relatively longer group on frontal margin of carapace, followed by little shorter group in middle and medium sized group in posterior third of the margin ( Fig. 5B View FIGURE 5 ). Marginal row of 35–40 (in large specimens up to 60) setae decreasing in size towards the posteroventral corner and followed by small spinules not arranged in groups ( Fig. 5J View FIGURE 5 ). Labrum ( Figs 5G–I View FIGURE 5 ). Labral keel in lateral view relatively short with moderately convex to wavy margin and obtuse tip ( Figs 5B&G–I View FIGURE 5 ). No ventral setules or denticles on labral keel. Well pronounced lateral horns with anterior depressions on labrum ( Fig. 6D View FIGURE 6 , between the bases of the antennae). Antennules ( Fig. 5E View FIGURE 5 ). About 2.5– three times as long as wide, sensory seta short and implanted between 1/2d and 1/3d from apex. Three rows of fine setules on dorsal margin. Aesthetascs shorter by one fourth of antennular corm and subequal in length. Second antennae ( Figs 5F View FIGURE 5 , 7B View FIGURE 7 ). Coxal setae not studied. Coxal spine large, conical ( Fig. 5F View FIGURE 5 ). Spinal formula 001/101, setal formula 113/003. First exopod seta on antenna long and narrow (exs 1 in Fig. 7B View FIGURE 7 ), reaching beyond last antennal segments; on external side of second exopod segment, group of six to eight long spinules ( Fig. 7B View FIGURE 7 ). Spine on first endopod segment as long as second endopod segment; main terminal spines on endo- and exopod well developed, as long as ultimate segment ( Figs 6F View FIGURE 6 , 7B View FIGURE 7 ). Terminal setae subequal in length and not reaching beyond dorsum of animal ( Fig. 6A View FIGURE 6 ).

Postabdomen ( Figs 5K–L View FIGURE 5 , 7C–E View FIGURE 7 , 8A–F View FIGURE 8 ). Highly variable. Relatively long, about 2.5 to three times as long as wide and parallel anal and ventral margins. Preanal, anal and postanal margins of similar length (postanal portion may be slightly longer than anal margin). Ventral margin as long as anal and postanal margin together. Anal margin completely straight, rarely concave just before preanal corner ( Figs 8B&F View FIGURE 8 ), but mostly ending abruptly before preanal corner ( Figs 5L View FIGURE 5 , 7D–E View FIGURE 7 ). Postanal margin relatively straight (not evenly rounded), tapering distally, distal margin protruding ( Figs 5K–L View FIGURE 5 , 8A–F View FIGURE 8 ). Preanal corner strongly developed, triangular, protruding beyond anal and postanal margins. Marginal denticles well developed, arranged in eight to ten postanal groups. These marginal denticles may be relatively long ( Fig. 5L View FIGURE 5 , 8D–F View FIGURE 8 ) or shorter ( Fig. 5L View FIGURE 5 ). Distal postanal marginal denticles consisting of two or more large spines, those closer to the anal margin in groups of three to four long spines of which distal element largest ( Figs 7C–E View FIGURE 7 ). Lateral fascicles five to seven groups in postanal portion, consisting of over 15 slender spinules in each group, parallel to each other, of similar thickness and slightly increasing in size distally ( Figs 5K View FIGURE 5 , 7C–E View FIGURE 7 ). Two to three clusters of marginal denticles and double row of fascicles in anal portion. Terminal claw ( Figs 5K–L View FIGURE 5 , 8A–G View FIGURE 8 ). As long as anal margin, relatively slender and straight ( Fig. 7C View FIGURE 7 ) to thicker and slightly curved ( Fig. 7D View FIGURE 7 ), implanted with setules along dorsal side ( Figs 5K–L View FIGURE 5 ). Long slender basal spine, about two to three times as long as claw width at base and almost reaching half of claw length. In populations from Aldabra Island ( Seychelles), terminal claw three times as long as claw width ( Fig. 8C View FIGURE 8 ). Group of three to five long basal spinules, continuing in row of setules along the dorsal margin of the basal spine ( Figs 5K–L View FIGURE 5 , 7D View FIGURE 7 ).

First maxilla ( Fig. 9A View FIGURE 9 ) with two long setulated setae.

Five pairs of limbs. First limb ( Figs 7F View FIGURE 7 , 8I–M View FIGURE 8 , 9B–D View FIGURE 9 ). Epipodite oval round without projection. First endite with three marginal setae of which the first well developed, second endite with three setae of which two longer (and subequal in size), third endite with four setae ( Fig. 9B View FIGURE 9 ); anterior elements on en1–2 present but minute, one on each endite ( Fig. 9C View FIGURE 9 ). ODL with one slender seta ( Fig. 9D View FIGURE 9 ) about as long as longest IDL seta; IDL with two setae, third seta reduced; no chitin ring in setae; armature of IDL setae a pecten of strong denticles decreasing in size proximally, thickness of these denticles varies between populations ( Figs 8I–M View FIGURE 8 ). Accessory seta present, plumose ( Fig. 9B View FIGURE 9 ). Anterior setule groups with three or more strong setules in each group, gradually decreasing in size ventrally. Ejector hooks slender, subequal, gnathobase with long single setulated seta ( Fig. 9B View FIGURE 9 ). Second limb ( Figs 9E–F View FIGURE 9 ). Exopodite elongated oval, with one long setulated seta implanted subapically ( Fig. 9E View FIGURE 9 ); endites with eight scrapers of which first longest, first four relatively long and slender and of similar morphology, with fine denticulation, scrapers three to five of same length; fifth scraper relatively thicker with shorter, stronger denticles and last three shorter by half than latter and with heavier denticles; gnathobasic ‘brush’ short with group of few long spinules, gnathobase with a sensillum and three elements of which the first is a straight seta; filter comb with seven setae of which first two (a–b) much shorter, first thick and brushlike with setules implanted around its distal half ( Fig. 9F View FIGURE 9 ). Third limb ( Figs 9G–K View FIGURE 9 ). Epipodite oval without projections; exopodite ( Fig. 9G View FIGURE 9 ) with rectangular corm and six large setae in 2+4 arrangement; first exopodite seta much longer than second; third exopodite seta more than two times as long as fifth exopodite seta, fourth seta long (longer than fifth seta), sixth seta narrower and longer than half fifth seta; the latter pappose in proximal half, strong setules in distal half ( Fig. 9H View FIGURE 9 ). Endites ( Fig. 9I View FIGURE 9 ) with external endite with three setae (1’–3’) of which first two scraper-like, of similar size and with minute element in between, third (3’) shorter and with long setules; four well developed plumose setae on inner side (1”–4”) of which first shorter; one element and four small setae on internal endite preceding gnathobase ( Fig. 9J View FIGURE 9 ); latter ( Fig. 9K View FIGURE 9 ) with a bottle-shaped sensillum and large plumose seta with two naked setae at its base. Filter comb ( Fig. 9I View FIGURE 9 ) with seven long setae.

Fourth limb ( Figs 9L–N View FIGURE 9 ). Pre-epipodite round, epipodite oval-round ( Fig. 9L View FIGURE 9 ), without projections. Exopodite ( Fig. 9L View FIGURE 9 ) square, with six plumose setae of which first two of similar size, third much longer, fourth shorter than but more than half size of fifth seta; length of fifth seta varies between populations, similar in size to sixth seta or clearly longer ( Fig. 9M View FIGURE 9 ). Endite ( Fig. 9N View FIGURE 9 ) with marginal row of four setae, first scraper-like and longer than flaming torch setae, following three ft setae with thick base, all of similar size, and one marginal round naked sensillum; gnathobase with one long setae, bent over endite and two reduced naked elements; on inner side, three well developed plumose setae (1”–3”) of which first shortest and a filter comb with five setae. Fifth limb ( Figs 9O–R View FIGURE 9 ). Pre-epipodite round; epipodite round oval, without projections. Exopodite shape broadly oval, about two times as long as wide, with straight to slightly convex expanded margin between setae three and four ( Figs 9O–P View FIGURE 9 ); four exopodite setae, gradually decreasing in size, first longest, oriented dorsally; fourth seta about half as long as third seta; inner lobe elongated oval, longer than wide, with long terminal setules; two slender endite setae (1’–2’) of which first longest and bent towards inner lobe ( Fig. 9Q View FIGURE 9 ); behind second endite seta, an elongated element with setulated apex ( Fig. 9R View FIGURE 9 ); gnathobase with a naked reduced bump and one seta ( Fig. 9Q View FIGURE 9 ).

Adult male ( Fig. 10A–C View FIGURE 10 ). Habitus ( Fig. 10A View FIGURE 10 ) smaller than female, 0.3–0.35mm, body rectangular with relatively straight dorsum, convex ventral margin. Strong striation on carapace as in female. Marginal setules on carapace longer in posterior half. Postabdomen ( Fig. 10C View FIGURE 10 ) narrow, long, 2.5 to three times as long as wide. Preanal corner small, dorsal and ventral margins parallel. Terminal claw short and thick, moderately curved and with basal spine about one third of length. Gonopores opening subapically and ventral to base of the terminal claws, no strong embayment here. Marginal groups of spinules on postabdomen unmerged setules, similar in size; lateral fascicles with setules relatively short and similar in length. Male IDL ( Fig. 10B View FIGURE 10 ) with three setae, of which two with fine pecten, third naked. Hook thick and short, clasper reaching beyond base, strongly curved and with two terminal rugae.

Ephippium . Black.

Differential Diagnosis. C. anemae n.sp. can be recognized by a relatively long (2.5 to three times as long as wide) postabdomen, long slender basal spine (up to three times as long as basal thickness of basal claw), reaching half of claw length and with group of three to five long basal spinules. Anal margin straight, with pronounced triangular preanal corner protruding beyond postanal margin and postanal margin with eight to eleven marginal denticle groups, fascicles without thicker distal spinule. First endopodal antennal spine not reaching beyond segment. In C. rectangula , postabdomen is shorter (two times as long as wide), with maximally seven marginal denticle groups and basal spine maximally one third of claw length. Diagnostic limb characters of anemae include IDL setae with setules or denticles but never with dominant heavy armature, reduced distal portion or chitineous ring as in C. rectangula . P2 of C. anemae with relatively slender scrapers, exIII with long fourth seta (short in C. rectangula !). Male of C. anemae with long slender postabdomen like in Alona monacantha (see Sinev, 2004a), three times as long as wide and with terminal gonopores. Postabdomen of males is therefore completely different from stout male postabdomen with subterminal gonopores in the “true” C. rectangula -complex ( Fig. 10D View FIGURE 10 ). For a comparison with related species in Africa, see under Discussion.

Variability. ( Figs 7C–E View FIGURE 7 , 8 View FIGURE 8 ). We noted variability in postabdomen shape ( Figs 5K–L View FIGURE 5 , 7C–E View FIGURE 7 , 8A–F View FIGURE 8 ), length of basal spine ( Figs 7C–E View FIGURE 7 , 8G View FIGURE 8 ), main head pore size ( Figs 7A View FIGURE 7 , 8H View FIGURE 8 ), labrum ( Figs 5G–I View FIGURE 5 ), IDL setulation on P1 ( Figs 8I–M View FIGURE 8 , 9D View FIGURE 9 ) and length of fifth seta on exIV ( Figs 9L–M View FIGURE 9 ), both within a single population as between populations (e.g., postabdomen morphology in three localities on Socotra Island; See Fig. 8 View FIGURE 8 ). Habitus of specimens from Sudan ( Fig. 5A View FIGURE 5 ) and Socotra (e.g., culture from Rewgid, Fig. 5B View FIGURE 5 ), also differed, Sudanese with a more strongly arched body than Socotrans. Labral keel varied from straight to wavy, e.g. between the three Socotran populations and Sudanese ( Figs 5G–I View FIGURE 5 ). Populations from Sudan, UAE and Uzbekistan have a relatively shorter postabdomen ( Figs 5K–L View FIGURE 5 , Fig. 8A View FIGURE 8 ) and stronger denticles on the IDL setae ( Figs 8I–L View FIGURE 8 ) than three Socotran populations ( Figs 8D–F, M View FIGURE 8 ), but also within a population the variability was high (e.g. Qaysoh population, Figs 8D–E View FIGURE 8 ). Specimens raised in the laboratory from Rewgid ( Socotra Island), had the finest IDL setulation ( Figs 8M View FIGURE 8 , 9D View FIGURE 9 ) and broadest head pores ( Fig. 8H View FIGURE 8 ). We found heaviest setulation ( Fig. 8I View FIGURE 8 ) and shortest postabdomen ( Fig. 8A View FIGURE 8 ) in specimens from Uzbekistan. We consider all these forms to be the same species, other limb characters and males (when present) being completely identical. A useful and “easy” character to recognize C. anemae sp. n. externally is the clear ornamentation of the valves, the relatively long postabdomen and the long basal spine, accompanied by long basal spinules.

Distribution and biology. The range of C. anemae sp. n. ( Fig. 11 View FIGURE 11 ) extends from E- and NE-Africa (Lake Chad, Egypt, Sudan, Lake Naivasha in Kenya) ( Ekman 1904 as A. bukobensis ; Rey & St-Jean 1969 and Jenkin 1934 as A. novae-zealandiae ; Delachaux 1917 as A. poppei ) Eastern Arabia ( UAE), Uzbekistan and oceanic islands in the Western Indian Ocean ( Socotra, Seychelles). Can be expected in the Sahara and the whole of the Arabian Peninsula ( Fig. 11 View FIGURE 11 ). C. anemae is common in temporary pools on rocks and sand in these highly arid regions where it forms egg-banks. On Socotra, we collected it from dried mud in small limestone rock pools sympatric with the endemic anostracan Branchipodopsis relictus in Rewgid ( Van Damme et al. 2004). Also in small rock holes (Noged) or coastal wetlands (Qaysoh) on the island. In our samples from Sudan, UAE, Socotra and Uzbekistan, we found the species commonly associated with Alona cambouei . On Socotra Island, C. anemae colonizes newly constructed rainwater catchments within weeks; there is no other way of reaching these but by wind. In our laboratory cultures, large populations developed three weeks after wetting of dry mud from rock pools, were easy to maintain and produced numerous ephippia. Nine years after collecting, mud from the Socotran localities still produces healthy populations in a few weeks. C. anemae is an active animal that feeds by scraping off detrital particles and filamentous algae and is a relatively slow swimmer.