Brancelia stochi Damme & Sinev, 2011

Damme, Kay Van & Sinev, Artem Y., 2011, A new genus of cave-dwelling microcrustaceans from the Dinaric Region (south-east Europe): adaptations of true stygobitic Cladocera (Crustacea: Branchiopoda), Zoological Journal of the Linnean Society 161 (1), pp. 31-52 : 42-46

publication ID	https://doi.org/ 10.1111/j.1096-3642.2010.00639.x
persistent identifier	https://treatment.plazi.org/id/039E87B1-FFF4-0B34-C9D6-F943FB01FAD0
treatment provided by	Valdenar
scientific name	Brancelia stochi
status	comb. nov.

Treatment

BRANCELIA STOCHI ( BRANCELJ, 1997) COMB. NOV.

( FIGS 6 View Figure 6 , 7 View Figure 7 )

= Alona stochi Brancelj, 1997 View in CoL ; Brancelj (1997: figs 1–3; pl. 1)

Type locality: Cave Kompoljska Jama , Dobrepolje, Central Slovenia . Type material see Brancelj (1997). Material examined: Three complete adult parthenogenetic females and two dissected parthenogenetic females from Cave Kompoljska Jama , Dobrepolje, central Slovenia. Leg. A. Brancelj, 25.vi.2007. Collection UGent .

Redescription of adult parthenogenetic female: Body ( Fig. 6A, B View Figure 6 ) ovoid, arched in lateral view, with strongly convex ventral margin, deepest point at middle; length 0.46–0.5 mm with body 1.3–1.4 times as long as high. Posterior valve margin strongly convex, with most posterior part in lower half ( Fig. 6A View Figure 6 ). Head with short blunt rostrum and widely obtuse tip, in lateral view not reaching over labral keel ( Fig. 6A View Figure 6 ); three major connected head pores and two lateral pores. Lateral pores at 1–1.5 times IP distance from midline. Carapace with faint wide striation ( Fig. 6B View Figure 6 ); posteroventral corner rounded, no notch; marginal setae ( Fig. 6D, E View Figure 6 ) with markedly longer anterior group ( Fig. 6D View Figure 6 ), median and posterior groups not markedly different and decreasing gradually in length towards posteroventral corner; row ending before posteroventral corner; setae relatively short and acute; posteroventral valve margin round, the angle not marked; setae followed by fine spinules ( Fig. 6E View Figure 6 ), as for genus. Postabdomen ( Fig. 6H View Figure 6 ) shape broad, about two to 2.5 times as long as wide, with deepest point at the preanal corner; postanal margin and anal margin of similar lengths or anal just longer; acute preanal angle, moderately expressed (triangular with broad base) and not projecting; postanal margin relatively straight to convex, tapering distally and not markedly separated from anal margin. Postabdomen armature with seven to eight postanal marginal denticles consisting of unmerged groups (long spines) and lateral fascicles as for genus, but with distalmost spinule relatively longer. Four to five lateral fascicle groups close to margin not accompanied by groups above it; marginal denticles in groups of three to four; in anal margin, about five similar groups with more spines per group. Terminal claw ( Fig. 6H View Figure 6 ) about as long as anal margin, curved. Basal spine three times as long as claw width at base, reaching about half its length and with basal spinules. First antenna ( Fig. 6F View Figure 6 ) as for genus, but about three times as long as wide and sensory seta reaching over antennular apex. Second antenna ( Fig. 6G View Figure 6 ) as for genus, with first exopodite spine about half second segment, terminal spines about half as long as terminal segments; first endopod seta on antenna reaching at least one-third of its length over antennal apex. Labrum ( Fig. 6C View Figure 6 ) as for genus with moderately convex, wavy margin and obtuse tip with an indentation; no ventral setules seen.

First maxilla ( Fig. 7A View Figure 7 ) with two thick, setulated setae. Five pairs of limbs. First limb ( Fig. 7A–D View Figure 7 ). First endite with two visible marginal setae; dorsal ‘seta’ not developed (as long as its base) ( Fig. 7B, C View Figure 7 ), second and third endites as for genus; anterior elements or soft setae on en1–2 reduced and about three times as long as wide, second shorter than first ( Fig. 7C View Figure 7 ). ODL with one slender seta with short setules in distal half, IDL as for genus, but naked seta less than a third of smallest IDL seta ( Fig. 7D View Figure 7 ). Both IDL setae just shorter than ODL seta ( Fig. 7D View Figure 7 ). Accessory seta present, well developed but shorter than IDL setae ( Fig. 7D View Figure 7 ). Anteriorly on corm, seven setule groups with more than six fine setules in each group; setules in each group do not decrease in size ventrally; ejector hooks as for genus, epipodite without projection and gnathobase a single seta on elevated base, with setulated apex ( Fig. 7B View Figure 7 ). Second limb ( Fig. 7E–G View Figure 7 ). Exopodite ( Fig. 7E View Figure 7 ) with welldeveloped seta, just longer than exopodite itself; exopodite oval and about as long as wide; endites with eight scrapers, all slender and with fine denticles, of which last (eight) shortest. Near base of first scraper, a large anterior soft seta or element, conical and about one-fifth of scraper length ( Fig. 7F View Figure 7 ). Scraper morphology ( Fig. 7E View Figure 7 ) as for B. sketi but with scraper four longer than scraper five. Gnathobasic ‘brush’ extended, gnathobase with a sensillum and three modified elements of which the first is a bent seta; filter comb with seven setae ( Fig. 7E View Figure 7 ) of which first ( Fig. 7G View Figure 7 ) shortest and thickest, second about three times as long. Third limb ( Fig. 7H–L View Figure 7 ). Exopodite ( Fig. 7H, I View Figure 7 ) with quadrangular corm and seven long setae in 2 + 5 arrangement; first two setae forming typical ‘fork’ (first longer than second), third exopodite seta longest, fourth and fifth unequal with fourth longer than fifth, setae six and seven unequal. Fifth seta not reaching half (almost a third) of fourth and sixth 1.7 times seventh seta. External endite ( Fig. 7J View Figure 7 ) with three setae (1′–3′) of which first two (1′–2′) long (at least twice length of seta 3′), first longer than second, both scraper-like and with two minute elements in between; rest of endite ( Fig. 7K, L View Figure 7 ) as for genus, with two naked elements near gnathobase seta. Fourth limb ( Fig. 7M View Figure 7 ). Epipodite ovalround, with short finger-like projection not reaching centre of exopodite. Exopodite rectangular, with six plumose setae of which first longer than second, both shorter than third, third seta as long as fifth; fifth and sixth setae of more similar thickness to each other than others, fifth longer than sixth. Fourth seta markedly shorter, nearly half of third seta. Endite as for genus, first scraper-like, twice first flaming torch seta; first flaming torch seta longer than wide, second and third about as long as wide, all decreasing in size towards gnathobase and one naked sensillum, about as long as wide, on margin; gnathobase with one seta, bent over endite, reaching just as far as second flaming torch seta; on inner side, three welldeveloped plumose setae increasing towards fc, which bears five setae. Fifth limb ( Fig. 7N, O View Figure 7 ). Epipodite oval round, with finger-like projection not reaching exopodite centre. Exopodite ( Fig. 7N View Figure 7 ) shape oval, about twice as long as wide, with concave margin between setae three and four; four exopodite setae, of

KEY TO ADULT PARTHENOGENETIC FEMALES OF BRANCELIA GEN. NOV. ( FIGS 8 View Figure 8 , 9 View Figure 9 )

We present an overview of adult parthenogenetic females of Brancelia in Figure 8 View Figure 8 . It illustrates the (ovoid) habitus of

Brancelia gen. nov., a character in which the animals differ most from other Aloninae , and complete regression of the ocelli and eyes. Key to species based on the postabdomen armature (see Fig. 9 View Figure 9 ):

1(2) Postabdomen with few (two to three) long marginal denticles per group in postanal portion and additional lateral fascicles above the main row ......................................................... Brancelia hercegovinae ( Brancelj, 1990)

2(1) Postabdomen with clusters of about four short marginal denticles each; no additional fascicles of setules above the main row .................................................................................................................................3

3(4) Basal spine long, about half terminal claw length ...................................... Brancelia stochi ( Brancelj, 1997)

4(3) Basal spine shorter, about a third terminal claw length................................ Brancelia sketi ( Brancelj, 1992) which first to third of similar lengths, shorter than exopodite length itself (0.7 times) and orientated dorsally; inner lobe elongate ( Fig. 7O View Figure 7 ), with longterminal setules, two thick endite setae (1′–2′) of similar size (first just longer than second), both shorter than inner lobe; behind second inner seta ( Fig. 7O View Figure 7 ), a naked element bent towards gnathobase; latter with two reduced naked elements and a filter comb with two setae. Adult male and ephippial female unknown.

Differential diagnosis: Brancelia stochi has a postabdomen with groups of marginal denticles (as in B. sketi ) and with the longest basal spine of the genus (reaching half of basal claw length). Second antenna with first endopod spine up to half of the second segment (this segment relatively short for genus). On limbs, B. stochi has a rudiment of the first seta in P1 (en1); P2 with fourth scraper longer than scrapers three or five. Specimens examined here with P4–P5 with short epipodite projections, not reaching over the exopodite centres.

Distribution and biology: Single cave in central Slovenia, Kompoljska Jama, which functions as a spring or sinkhole in periods of high precipitation or snow melt ( Brancelj, 1997). As previous species, B. stochi is a stygobiont restricted to topmost part of the saturated zone of the karst ( Brancelj & Dumont, 2007). Accompanied by true cave-dwellers like Proteus anguinus Laurenti, 1768 , Troglocaris schmidti Dormitzer, 1853 , Troglodiaptomus sketi Petkovski, 1978 , and Elaphoidella stammeri Chappuis, 1936 , but not found exclusively in presence of stygobionts; the habitat is a rocky/sandy bottom with fine layer of clay with pH ~7.5, water temperatures (6.2–) 10.2 °C, oxygen close to saturation (7.2–11.4 mg L- 1) (milligram per Liter), conductivity 352 MS cm-1 (microsiemens per centimeter), and low organic content ( Brancelj, 1997). Live as for B. sketi (A. Brancelj, pers. comm.)

46 K. VAN DAMME and A. Y. SINEV nae to the South Adriatic water basin (Split/ Dubrovnik), and there is no connection between the three basins ( Brancelj, 1997; pers. comm.). The two Slovenian taxa ( B. stochi and B. sketi ) belong to different drainage areas even within Slovenia ( Brancelj, 1997). However, morphology confirms a closer relationship between the Slovenian species, suggested by the scrapers (P2) and marginal denticles (PA) ( Table 1). We can confirm that all three are valid species that underwent a separate evolution. Interspecific variation in Brancelia gen. nov. is strong, mainly found in the armature of postabdomen, P2 (scraper lengths), P3 and P4 (exopodite setae), and in epipodite projections ( Table 1).