Gammarus hypolithicus, Hou & Li, 2010
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publication ID |
https://doi.org/ 10.1111/j.1096-3642.2009.00603.x |
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https://treatment.plazi.org/id/AD798550-F10C-FFBF-FF2E-D5D4FE9DB901 |
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Valdenar |
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Gammarus hypolithicus |
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sp. nov. |
GAMMARUS HYPOLITHICUS SP. NOV. ( FIGS 14–18 View Figure 14 View Figure 15 View Figure 16 View Figure 17 View Figure 18 )
Synonymy: Gammarus sp3 Hou et al., 2007: 599.
Material examined: Holotype (IZCAS-I-A317), male, Baishishan Mt. (39°12′N, 114°36′E), altitude 2096 m, Laiyuan County, Hebei Province, collected by Z. Hou and Y. Lin, 5.ix.2004 GoogleMaps . Paratypes (from IZCAS-I- A317-2 to IZCAS-I-A317-24): 15 males, eight females, same locality with holotype GoogleMaps .
Etymology: The epithet of the species name is from the habitat, where the new species was found under stone.
Diagnosis: Pereopods 3 and 4 with long setae on posterior margins; pereopods 5–7 slender; epimeral plates 1–3 subacute in posterodistal corners; urosomites 1–3 flat; inner ramus of uropod 3 about 0.6 times the length of outer ramus, both rami of uropod 3 with plumose setae; telson with basolateral spines and long setae.
Description
Holotype: male
Body length: 12.3 mm.
Head ( Fig. 14A View Figure 14 ): eyes reniform, 1.6 times as long as wide; inferior antennal sinus distinct, ventral recessed margin weakly curving.
Antenna 1 ( Fig. 14B View Figure 14 ): peduncular articles 1–3 in length ratio 1: 0.7: 0.4, with short lateral and distal setae; flagellum with 30 articles, aesthetascs present from article 4–26; accessory flagellum with five articles; both primary and accessory flagella with short distal setae.
Antenna 2 ( Fig. 14C View Figure 14 ): 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 14 articles, calceoli present in article 1–7.
Upper lip ( Fig. 14D View Figure 14 ): convex, with minute setae.
Left mandible ( Fig. 14E View Figure 14 ): 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 14 marginal setae, article 3 about 0.7 times as long as article 2, with five A-setae, five B-setae, a row of 17 D-setae, and five E-setae.
Right mandible ( Fig. 14F View Figure 14 ): incisor with 4 teeth, lacinia mobilis bifurcate, with small teeth.
Lower lip ( Fig. 14G View Figure 14 ): inner lobe absent.
Maxilla 1 ( Fig. 14H, I View Figure 14 ): asymmetrical, left inner plate with a row of 14 plumose setae; outer plate with 11 serrated apical spines, each spine with small teeth; second article of palp with eight slender spines and four stiff setae on medial surface; right palp wider, article 2 with five stout spines, one pectinate spine, and one seta.
Maxilla 2 ( Fig. 14J View Figure 14 ): inner plate with a row of 15 plumose setae and many setules on medial surface; outer plate with stiff apical setae and setules on lateral margin.
Maxilliped ( Fig. 14K, L View Figure 14 ): inner plate with three stout apical and one subapical spines; outer plate with 14 blade spines, eight pectinate spines; palp article 4 hooked, with a group of setae at hinge of unguis.
Gnathopod 1 ( Fig. 15A, C View Figure 15 ): 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, 1.1 times as long as wide, about 0.6 times as long as propodus; propodus oval, palm oblique, with one medial spine, 17 spines on posterior margin; dactylus with one seta on outer margin and two short setae at hinge of unguis.
Gnathopod 2 ( Fig. 15B, D View Figure 15 ): 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, 1.6 times as long as wide, about 0.7 times as long as propodus; propodus subrectangular, palm margin subacute, with one medial spine, two spines on medial posterodistal corner, and two spines on lateral posterodistal corner; dactylus with two setae near the hinge of unguis.
Pereopod 3 ( Fig. 16A, F View Figure 16 ): 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 weakly curled 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. 16B, G View Figure 16 ): coxal plate with three setae on anterior corner and eight 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. 16C, H View Figure 16 ): coxal plate with one seta on anterior corner and two setae on posterodistal corner; basis posterior margin straight, posterior corner subquadrate, with one long seta and five spines on anterior margin and a row of nine 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 two setae at hinge of unguis.
Pereopod 6 ( Fig. 16D, I View Figure 16 ): coxal plate with three setae on posterodistal corner; basis elongate, with two groups of long setae and four spines on anterior margin, posterior margin proximally broad, distally narrow, with a row of 13 setae, inner surface with one seta; 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. 16E, J View Figure 16 ): coxal plate with two setae on anterior margin and four setae on posterior margin; basis with four long setae and a row of five spines on anterior margin, posterior margin expanded, shape convex, with 15 setae on posterior margin, inner surface with one spine accompanied by two setae; merus to propodus with two to four groups of spines accompanied by few short setae on anterior margin, and propodus with two groups of setae on posterior margin; dactylus with one plumose seta on posterior margin and two stiff setae 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. 15E–G View Figure 15 ): epimeron 1 ventrally rounded, with eight long setae and two stiff setae on anterior corner, and three setae on posterior margin; epimeron 2 with one long seta on anterior corner, one subventral spine and two spines on ventral margin, posterodistal corner weakly produced, subacute, with five setae on posterior margin; epimeron 3 with four long setae on anterior corner, three spines on ventral margin, posterodistal corner weakly produced, subacute, with three setae on posterior margin.
Pleopods 1–3 subequal ( Fig. 17A–C View Figure 17 ), peduncle with long facial and marginal setae, with two retinacula accompanied by one to two setae on anterodistal corner; both inner and outer rami fringed with plumose setae.
Urosomites 1–3 dorsally flat ( Fig. 17G View Figure 17 ), urosomite 1 with 1–1–1–1 spine with short setae on dorsal margin; urosomite 2 with 2–1–1–2 spines accompanied by short setae on dorsal margin; urosomite 3 with two spines accompanied by setae on each side and one or no seta on dorsal margin.
Uropod 1 ( Fig. 17D View Figure 17 ): peduncle with one basofacial spine, three spines on outer margin, one spine on inner margin, with one and two spines on inner and outer distal corners, respectively; outer ramus with one spine on outer margin and one spine on inner margin; inner ramus with one spine on inner margin, both rami with five distal spines.
Uropod 2 ( Fig. 17E View Figure 17 ): peduncle with two and one spines on outer and inner margin, respectively, one spine on inner and outer corner, respectively; outer and inner rami with one spine on outer and inner margin, respectively.
Uropod 3 ( Fig. 17F View Figure 17 ): peduncle with one lateral spine and six distal spines; inner ramus 1.4 times the length of peduncle, reaching 0.6 times the length of outer ramus, with two spines on lateral margin and two 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 as long as adjacent spines.
Telson ( Fig. 15H View Figure 15 ): deeply cleft, 0.9 times as long as wide, each lobe with two distal spines accompanied by long setae, one basolateral spine, and long setae on lateral surface.
Female, paratype (IZCAS-I-A317-2)
Body length: 10.3 mm.
Gnathopod 1 ( Fig. 18A, C View Figure 18 ): coxal plate with two setae on anterior corner and one seta on posterior margin; propodus oval, palm margin not as oblique as that of male, with eight spines on posterodistal corner; dactylus with one seta on outer margin and two setae at hinge of unguis.
Gnathopod 2 ( Fig. 18B, D View Figure 18 ): propodus subrectangular, palm margin transverse, with five spines on posterodistal corner; dactylus with one seta on outer margin and one seta at hinge of unguis.
Pereopods 3 and 4 with straight setae on posterior margin.
Uropod 3 ( Fig. 17H View Figure 17 ): inner ramus about 0.6 times as long as outer ramus, both rami with plumose setae, terminal article of outer ramus as long as adjacent spines.
Telson ( Fig. 17I View Figure 17 ): cleft, 0.8 times as long as wide, each lobe with two distal spines accompanied by long setae, one basolateral spine, and long setae on dorsal surface.
Oostegites ( Fig. 18E–H View Figure 18 ): oostegite of gnathopod 2 broad, with long marginal setae, oostegite of pereopods 3 and 4 elongate, oostegite of pereopod 5 smallest.
Habitat: Gammarus hypolithicus sp. nov. was only found in the type locality, a small pool near the peak of Baishishan Mt. This pool was less than 1 m 2, and water fell from a height of 10 m.
Remarks: Gammarus hypolithicus sp. nov. differs from G. nekkensis (state in parentheses) in long straight setae on posterior margin of pereopods 3 and 4 (curled setae), both margins of rami of uropod 3 with plumose setae (outer margin of outer ramus with simple setae). Gammarus hypolithicus sp. nov. is distinguished from G. clarus (state in parentheses) by epimeral plate 3 with small acute tooth (acute); urosomites 1–2 flat, with four groups of spines and setae on dorsal margin (elevated, with three groups of spines and setae on dorsal margin); telson with long setae (short setae).
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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