Gammarus clarus, Hou & Li, 2010
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publication ID |
https://doi.org/ 10.1111/j.1096-3642.2009.00603.x |
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persistent identifier |
https://treatment.plazi.org/id/AD798550-F114-FFB7-FCE4-D0ADFB91BF1A |
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Valdenar |
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Gammarus clarus |
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sp. nov. |
GAMMARUS CLARUS SP. NOV. ( FIGS 9–13 View Figure 9 View Figure 10 View Figure 11 View Figure 12 View Figure 13 )
Synonymy: Gammarus sp2 Hou et al., 2007: 599.
Material examined: Holotype (IZCAS-I-A315), male, headwaters of Jumahe River (39°18′N, 114°42′E), altitude 836 m, Laiyuan County, Hebei Province, collected by Z. Hou and Y. Lin, 5.ix.2004 GoogleMaps . Paratypes (from IZCAS-I-A315-2 to IZCAS-I-A315-14): eight males and five females, same locality as holotype GoogleMaps .
Other material: 125 males and 108 females (from IZCAS-I-A314-1 to IZCAS-I-A314-233) (voucher number 314), Baihe River (40°36′N, 116°12′E), lower river of Baidaohe Reservoir , Yanqing County, Beijing, collected by S. Li and Z. Hou, 7.iv.2004 GoogleMaps . Fifteen males and 12 females (from IZCAS-I-A355-1 to IZCAS-I- A355-27) (voucher number 355), a brook from Hutouliang Village (40°6′N, 114°6′E), Yangyuan County, Hebei Province, collected by S. Li, 12.v.2002 GoogleMaps .
Etymology: The specific name ‘clarus’ is Latin for ‘clear’, referring to the habitat with clear water and no signs of pollution.
Diagnosis: Peduncular articles of antenna 2 with short setae, calceoli present; pereopods 3 and 4 with long straight setae on posterior margins; basis of pereopods 6 and 7 proximally broad, distally narrow; epimeral plates 2–3 acute in posterodistal corners; urosomites 1–2 weakly elevated; inner ramus of uropod 3 about 0.7 times the length of the outer ramus, both rami of uropod 3 densely set with plumose setae.
Description
Holotype: male
Body length: 13.5 mm.
Head ( Fig. 9A View Figure 9 ): eyes reniform, 2.2 times as long as wide; inferior antennal sinus distinct, ventral recessed margin curving.
Antenna 1 ( Fig. 9B View Figure 9 ): peduncular articles 1–3 in length ratio 1: 0.8: 0.4, with short lateral and distal setae; flagellum with 28 articles, aesthetascs present except for the last two articles; accessory flagellum with four articles; both primary and accessory flagella with short distal setae.
Antenna 2 ( Fig. 9C View Figure 9 ): peduncular article 4 about as long as article 5, both with three to four groups of setae along anterior and posterior margins, setae shorter than the width of peduncles; flagellum with 13 articles, calceoli present.
Upper lip ( Fig. 9D View Figure 9 ): convex, with minute setae.
Left mandible ( Fig. 9E View Figure 9 ): incisor with five teeth; lacinia mobilis with four teeth; spine row with seven pairs of setae; molar with one plumose seta; palp article 2 with 12 marginal setae, article 3 about 0.73 times as long as article 2, with five A-setae, two groups of B-setae (with two and four setae, respectively), a row of 21 D-setae, and five E-setae.
Right mandible ( Fig. 9F View Figure 9 ): incisor with four teeth, lacinia mobilis bifurcate, with small teeth.
Lower lip ( Fig. 9G View Figure 9 ): inner lobe absent.
Maxilla 1 ( Fig. 9H, I View Figure 9 ): asymmetrical, left inner plate with a row of 16 plumose setae; outer plate with 11 serrated apical spines, each spine with small teeth; second article of palp with seven slender spines and three stiff setae on medial surface; right palp wider, article 2 with five stout spines, one pectinate spine, and one seta.
Maxilla 2 ( Fig. 9J View Figure 9 ): inner plate with a row of 17 plumose setae and many setules on medial surface; outer plate with stiff apical setae and setules on lateral margin.
Maxilliped ( Fig. 9K View Figure 9 ): inner plate with three stout apical and one subapical spines; outer plate with 13 blade spines and three pectinate spines; palp article 4 hooked, with a group of setae at hinge of unguis.
Gnathopod 1 ( Fig. 10A, C View Figure 10 ): coxal plate subrectangular, with two setae on anterior corner and one seta on posterior corner; basis with long setae on anterior and posterior margins; carpus short, 1.4 times as long as wide, about 0.7 times as long as propodus; propodus oval, palm oblique, with one medial spine and 21 spines on posterior margin; dactylus with one seta on outer margin.
Gnathopod 2 ( Fig. 10B, D View Figure 10 ): coxal plate with three setae on anterior corner and one seta on posterior corner; basis with long setae along anteroproximal and posterior margins; carpus with parallel margins, 1.4 times as long as wide, 0.7 times as long as propodus; propodus subrectangular, palm margin subacute, with one medial spine and three spines on medial posterodistal corner and three spines on lateral posterodistal corner; dactylus with one seta on outer margin.
Pereopod 3 ( Fig. 11A View Figure 11 ): coxal plate with three setae on anterior corner and one seta on posterior corner; basis with long setae on posterior margin; merus densely set with long and straight setae on posterior margin, merus with spines accompanied by setae on anterior margin, carpus and propodus with spines and long straight setae on posterior margin; dactylus with one plumose seta on posterior margin and two setae at hinge of unguis.
Pereopod 4 ( Fig. 11B, G View Figure 11 ): coxal plate with three setae on anterior corner and four setae on posterior margin, posterior margin excavated; basis with groups of long setae on posterior margin; merus to propodus with straight setae on posterior margin, carpus and propodus with spines on posterior margin; dactylus with one plumose seta on posterior margin and two stiff setae at hinge of unguis.
Pereopods 5–7 slender.
Pereopod 5 ( Fig. 11C View Figure 11 ): coxal plate with one seta on anterior corner and three setae on posterodistal corner; basis posterior margin straight, posterior corner subquadrate, with long setae and four spines on anterior margin, a row of ten setae on posterior margin; merus to propodus with spines along anterior and posterior margins accompanied by few short setae; dactylus with one seta on posterior margin and one seta at hinge of unguis.
Pereopod 6 ( Fig. 11D View Figure 11 ): coxal plate with one seta on anterior corner and one seta on posterodistal corner; basis elongate, with one group of long setae and three spines on anterior margin, posterior margin dwindled distally and projected on posterodistal corner, with a row of nine setae; merus to propodus with groups of spines accompanied by short setae along anterior and posterior margins; dactylus with one plumose seta on posterior margin and one seta at hinge of unguis.
Pereopod 7 ( Fig. 11E, F View Figure 11 ): coxal plate with two setae on anterior margin and four setae on posterior margin; basis with a group of five long setae and a row of four spines on anterior margin, posterior margin weakly expanded with nine setae on posterior margin, posterodistal corner subquadrate, inner surface with one spine accompanied by three setae; merus to propodus with two to four groups of spines accompanied by few short setae on anterior margin, propodus with two groups of setae and one spine on posterior margin; dactylus with one plumose seta on posterior margin and one stiff seta at hinge of unguis.
Coxal gills: coxal gill of gnathopod 2 and gills of pereopods 3–5 a little shorter than bases; gill of pereopod 6 about half length of basis; gill of pereopod 7 smallest, less than half of basis.
Epimeral plates ( Fig. 10E–G View Figure 10 ): epimeron 1 ventrally rounded, with six long setae and two spines on anterior corner and two setae on posterior margin; epimeron 2 with two subventral spines and three spines on ventral margin, posterodistal corner weakly acute, with three setae on posterior margin; epimeron 3 with three long setae on anterior margin, four spines on ventral margin, posterodistal corner acute, with three setae on posterior margin.
Pleopods 1–3 subequal ( Fig. 12A–C View Figure 12 ), peduncle with long facial and marginal setae, with two retinacula accompanied by one to two setae on anterodistal corner; both inner and outer rami with 20–23 articles, fringed with plumose setae.
Urosomites 1 and 2 weakly elevated ( Fig. 10H, I View Figure 10 ), urosomite 1 with 4–3–4 spines accompanied by short setae on dorsal margin; urosomite 2 with 3–2–3 spines accompanied by short setae; urosomite 3 with 3–2–3 spines accompanied by setae.
Uropod 1 ( Fig. 12D View Figure 12 ): peduncle with one basofacial spine, three spines on outer margin, three spines on inner margin, and two and one spines on outer and inner distal corners, respectively; outer ramus with one spine on outer margin and two spines on inner margin; inner ramus with two spines on inner margin, both rami with five distal spines.
Uropod 2 ( Fig. 12E View Figure 12 ): peduncle with two and three spines on outer and inner margins, respectively, one spine on inner and outer corners, respectively; outer ramus with two spines on outer and inner margins, respectively; inner ramus with two and one spines on outer and inner margins, respectively.
Uropod 3 ( Fig. 12F View Figure 12 ): peduncle with lateral setae and distal spines; inner ramus 1.8 times as long as peduncle, reaching 0.7 times the length of outer ramus, with two spines on lateral margin and three distal spines; article 1 of outer ramus with one single spine and three pairs of spines on outer margin, and two pairs of spines on distal margin, both margins densely set with plumose and simple setae, terminal article longer than adjacent spines.
Telson ( Fig. 10J View Figure 10 ): deeply cleft, 1.2 times as long as wide, each lobe with two distal spines accompanied by long setae, one basolateral spine and several short setae on lateral surface.
Female, paratype (IZCAS-I-A315-2)
Body length 13.2 mm, with 36 eggs.
Antenna 2 ( Fig. 13A View Figure 13 ): peduncular articles 4 and 5 with setae along inner margin, setae longer than the width of peduncle.
Gnathopod 1 ( Fig. 13B, D View Figure 13 ): coxal plate with three setae on anterior corner and one seta on posterior margin; propodus oval, palm margin not as oblique as that of male, with 14 spines on posterior margin; dactylus with one seta on outer margin.
Gnathopod 2 ( Fig. 13C, E View Figure 13 ): propodus subrectangular, palm margin subacute, with four spines on posterodistal corner; dactylus with one seta on outer margin.
Pereopods 3 and 4 with straight setae on posterior margin.
Uropod 3: inner ramus about 0.7 times as long as outer ramus, both rami with plumose setae, terminal article of outer ramus longer than adjacent spines.
Telson ( Fig. 13E View Figure 13 ): cleft, 1.1 times as long as wide, each lobe with two distal spines accompanied by long setae, three or one basolateral spines and short setae on dorsal surface.
Oostegites ( Fig. 12G–J View Figure 12 ): oostegite of gnathopod 2 broad, with long marginal setae, oostegite of pereopods 3 and 4 elongate, oostegite of pereopod 5 smallest.
Habitat: Gammarus clarus sp. nov. was found in the source of Jumahe River and along the river, also occurred along Sangan River. All collection sites were at the banks of small streams.
Remarks: Gammarus clarus is closely related to G. nekkensis in body shape. Gammarus clarus differs from G. nekkensis (states in parentheses) in inner ramus reaching 0.7 times the length of outer ramus (0.5), both rami fringed with simple and plumose setae (simple setae on outer margin of outer ramus); pereopod 3 with straight setae (curled setae); urosomites 1–2 elevated (flat).
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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