Alona ossiani subsp. herricki Sinev, 2013, ssp. nov.
Creators: name: Sinev, Artem Y.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Branchiopoda
Diplostraca
Alona
Alona ossiani
Alona ossiani herricki

description: Alona ossiani herricki ssp. nov.
(Figs. 1–3)
Etymology. the subspecies name honors Claurence Luther Herrick, famous American zoologist and carcinologist of the XIX century.
Type locality. Sebago Lake, Cumberland county, Maine, USA, 8.8.1966, coll. D. G. Frey, DGF 1900.
Type material. Holotype: parthenogenetic female from the type location, USNM 1207845.
Allotype: male from the type locality, USNM 1207846.
Paratypes: over 30 females and 5 males from the type locality, USNM 1207837; several parthenogenetic and ephippial females from Lake Inez, Missoula County, Montana, 12.11.1979, coll. J.R. MCAuliffe, DGF 583; 6 parthenogenetic females from from Trickey pond, Cumberland county, Maine, USA, 11.08.1966, DGF 1935; 4 parthenogenetic females, 2 males from Pallete lake, Vilas county, Wisconsin, 29.10.1981, DFG 6141; several parthenogenetic and ephippial females and 5 males from Martin-Olivier channel, La Grande county, Indiana, USA, 12.11.1967, DGF 2515; several parthenogenetic females from Jacobs pond, DGF 6210; several parthenogenetic females and 1 male from Atwood lake, La Grande county, Indiana, USA, 12.11.1967, DGF 2505.
Diagnosis. Alona ossiani herricki ssp. nov. differs from A. o. ossiani (nominative subspecies) by the presence of 2–3 marginal denticles on postanal angle of male postabdomen, in nominative subspecies all marginal denticles in male are substituted by groups of very short setules (Sars, 1901; Sinev, 1998).
Description. Parthenogenetic female. General. In lateral view, body subrectangular, low in juvenile females (Fig.1 A–B); oval, of moderate height in adults (Fig. 1 C); moderately compressed laterally. Maximum height at the middle of the body. In adults height/length ratio about 0.6.
Carapace. Dorsal margin convex; postero-dorsal and postero-ventral angles broadly rounded. Posterior margin weakly convex. Antero-ventral angle rounded. Ventral margin (Fig. 1 D) weakly convex to straight, with 70–85 setae. About 25 anteriormost setae very long, next 15 seta short, posterior 40–45 setae of moderate length, decreasing in length posteriorly. Postero-dorsal angle (Fig. 1 E–F) with 6–8 groups of large setules, with 4–7 setules in each, length and thickness of setules in groups increasing posteriorly. A row of about 80 setules of variable length along posterior margin on inner side of carapace, these setules not organized into groups. Carapace ornamentation as weakly developed longitudinal lines and dense longitudinal striae between them.
Head relatively small, low triangle-rounded in lateral view. In lateral view rostrum relatively narrow, protruding downwards. Ocellus of moderate size; in adults eye of similar size to ocellus. Distance from tip of rostrum to ocellus 1.5 times greater than that between ocellus and eye. Head shield (Fig. 1 G–H) with maximum width behind mandibular articulation, covered by fine striae, same as on valves. Rostrum short and rounded. Posterior margin as prominent, acute distal angle. Two major head pores (Fig. 1 I) of same size, with a narrow connection between them. PP about 1.5 IP in adults. Lateral head pores located in small depressions about 0.7–0.9 IP distance from midline, at level of anterior major head pore or slightly before it. Striae absent around head pores. A small pore like thickening is located behind the posterior angle of head shield.
Labrum (Fig.1 J) of moderate size. Labral keel moderately wide, with a blunt apex. Anterior margin of keel convex or polygonal, posterior margin weakly convex to straight, with two clusters of short setules.
Thorax two times longer than abdomen. Dorsal surface of abdominal segments not saddle-shaped. Abdominal joint not developed.
Postabdomen (Fig. 2 A–B) large, subrectangular, moderately high, with parallel margins, weakly narrowing at the end. Length about 2.5 height. Ventral margin straight. Basis of claws bordered from distal margin by clear incision. Distal margin from almost straight to weakly convex; distal angle rounded. Dorsal margin weakly convex in postanal portion and weakly concave in anal one, with distal part about 2.5 times longer than preanal one, with postanal portion 2.5–2.8 times longer than anal one. Preanal angle well expressed, postanal angle not defined. Preanal margin almost straight. Postanal margin (Fig. 2 C) with 12–14 well-developed, single sharp denticles, each with 1–7 (usually 3–5) spinules along anterior margin; size of denticles increasing distally. Length of longest denticles about 1.5 the width of base of postabdominal claw, more than 3 times exceeding the width of the denticle base. Postanal portion with 11–12 broad lateral fascicles, posteriormost setae of each fascicle longest, thicker than others, slightly shorter than neighboring marginal denticles. Anal portion with several smaller fascicles, spaced irregularly. Postabdominal claw (Fig. 2 D) of moderate length, slightly longer than preanal portion of postabdomen. Basal spine long and slender, about 0.25–0.35 length of the claw. A row of 7–10 long setules between basal spine and the base of postabdomen.
Antennule (Fig. 2 E) of moderate size, length about 3 width; cluster of 3–4 long setules at anterior face about one third the length of antennule, and 2–3 transverse rows of very short setules below it. Antennular seta thin, more than 2/3 length of antennule, arising terminally. Nine terminal aestetascs, two of them long and thin, little shorter than antennule itself, all other much shorter, about 1/2–1/3 the length of antennule.
Antenna relatively short (Fig. 2 F). Antennal formula: setae 0-0-3/1-1-3; spines 1-0-1/0-0-1. Basal segment robust, with a very short seta between branches; branches relatively short, all segments cylindrical, slender, middle segment in each branch shorter than others, two times shorter than basal segment. Seta arising from basal segment of endopodite thin, not reaching the end of endopodite. Seta arising from middle segment of endopodite, of similar size to apical setae. Two apical setae on exopodite and one on endopodite with a very long spinule at the point of articulation. Spine on basal segment of exopodite significantly longer than middle segment. Spines on apical segments shorter than apical segments.
Limb I of moderate size (Fig. 3 A–B). Epipodite oval, with very short projection. Accessory seta long, only slightly shorter than ODL seta, with long setules in distal part. ODL with one seta. IDL with three setae and several clusters of hard setules. IDL seta 1 large and broad, claw-like, strongly curved, slightly longer than seta 2; IDL setae 2 and 3 with thin setules in distal part, seta 3 slightly shorter than ODL seta, seta 2 about 2/3 the length of seta 3. Endite 3 with four setae subequal in length. Endite 2 (Fig. 3 C) with two long distally setulated setae (e–f), a shorter seta near their base (d) and a naked inner seta and small sensillum on anterior face of limb; seta e very long, two times longer than seta f, almost as long as limb itself. Endite 1 with two 2-segmented setae, both setulated in distal part, a flat plumose seta pointed the limb base, and a naked inner seta and small sensillum on anterior face of limb. Seven-eight rows of thin long setules on ventral face of limb. Two ejector hooks, one slightly shorter than other. Maxillar process elongated, with short setulated seta in distal part.
Limb II subtriangular (Fig.3 D). Exopodite elongated, of irregular shape, with slender seta as long as exopodite itself and cluster of very long setules in distal part. Eight scraping spines, three basalmost spines subequal in length, others increasing in length distally. Size of denticles on basal part of spines evenly decreasing from basal to distal spines. Distal armature of gnathobase with four elements. Filter plate II with seven setae, the posteriormost member shorter than others.
Limb III (Fig. 3 E–G). Epipodite oval, without finger-like projection. Exopodite of irregular shape, with seven setae. Seta 3 being longest, setae 6 and 7 subequal in length, about 1/3 length of seta 3, other setae very short. Setae 1–5 plumose, seta 6 with three rows of hard setules in distal part, seta 7 with thin setules in distal part. Distal endite with 3 setae, two distalmost members scraping, slender, sharp, with denticles in distal part; short bottle-shaped sensillum located between their bases; basalmost seta flattened, as long as scraping setae, bilaterally armed with long setules. Basal endite with 4 plumose setae increasing in size basally. Four pointed soft setae increasing in size basally, a small bottle-shaped sensillum near the distalmost seta. Distal armature of gnathobase with four elements; the first one elongated, narrowing distally sensillum, the second a strongly geniculated seta, and the third and fourth are spines. Filter plate III with seven setae.
Limb IV (Fig. 3 H–J). Pre-epipodite setulated; epipodite oval, with finger-like projection shorter than exopodite itself. Exopodite subquadrangular, with six setae. Seta 1 and 2 being longest, equal in length; seta 3 slightly shorter, bending toward inner portion of limb; seta 4 about half length of seta 1, bending toward inner portion of limb; setae 5–6 subequal in length, slightly shorter than seta 4. Setae 1–4 plumose, setae 5–6 with short setules. Inner portion of limb IV with four setae and bottle-shaped sensillum. Scraping seta slender, three flaming-torch seta decreasing in size basally, with 7–9 long setules each. Small sensillum between the base of middle and basal flaming-torch setae. Three soft setae slightly increasing in size basally. Gnathobase with one long 2-segmented setae, a small hillock distally and a sensillum. Filter plate IV with five setae.
Limb V (Fig. 3 K–L). Pre-epipodite setulated; epipodite oval, with finger-like projection as long as epipodite itself. Exopodite divided into two lobes, with four plumose setae: setae 1–3 long, subequal in length; seta 4 three times shorter. Inner lobe broad, rounded with setulated inner margin. At inner face, two setae densely setulated in distal part, one of them very long, slightly longer than exopodite setae, the other three times shorter. Filter plate V with three setae and with two broad-based sensilla-like structures between inner face setae and filter plate.
Limb VI (Fig. 3 M) as oval lobe with setulated margin.
Ephippial female (Fig. 1 K). Body slightly higher than in parthenogenetic female; ephippium yellow-brown without specific sculpture.
Male. General. Body (Fig 1 L) low oval, with maximum height at the middle, height/length ratio about 0.54.
Postabdomen (Fig. 2 G) of moderate size, with almost parallel margins. Length about 2.5 height. Ventral margin straight. Postabdominal claw situated on small protrusion in ventral portion of convex distal margin. The sperm ducts open above the protrusion; posteroventral and posterodorsal angles rounded. Dorsal margin weakly convex in postanal portion and weakly concave in anal one. Preanal angle weakly defined; postanal angle not defined. Preanal margin almost straight. Distal portion of postabdomen two times longer than preanal one, postanal portion two times longer than anal one. Clusters of thin setules in place of female marginal denticles on postanal margin, 2–3 groups of distinctive spine-like denticles near the postanal angle. Lateral fascicles of setules as in female. Postabdominal claw weakly curved, shorter than in female, as long as preanal margin. Basal spine about 0.25–0.3 length of claw.
Antennule (Fig. 2 H) broader than in female, with 12 long terminal aesthetascs, two longest almost as long as antennule itself, others about 2/3 length of antennule. Male seta subterminal, about 1/3 length of antennule.
Thoracic limb I (Fig. 3 N–O) with U-shaped copulatory hook, half as long as limb itself. IDL with four setae: IDL seta 1 not hook-like, but still well-developed, about 2/3 length of IDL seta 2; IDL setae 2 and 3 much thinner and two times shorter than in female; male seta curved, as long as seta 2. Copulatory brush seta about 2/3 length of IDL seta 2. Ventral face of the limb under the copulatory brush with row of 10–12 stiff setules of moderate length, and outer face of endite 3 with a row of about 10 shorter setules, there is a wide gap between these two rows. Inner seta (1) of endite 3 thinner than in female, with long setules distally.
Size. Females of first juvenile instar: length 0.51–0.56 mm; height 0.27–0.29 mm. Females of second juvenile instar: length 0.58–0.63 mm; height 0.31–0.34 mm. Adult females: length 0.75–0.96 mm; height 0.45–0.52 mm. Adult male: length 0.60–0.63 mm; height 0.32–0.34 mm.
description: Published as part of Sinev, Artem Y., 2013, Cladocerans of Alona affinis group (Cladocera: Anomopoda: Chydoridae) from North America, pp. 329-343 in Zootaxa 3693 (3) on pages 330-335, DOI: 10.11646/zootaxa.3693.3.3, http://zenodo.org/record/223918