Jesogammarus (Jesogammarus) fontanus, Hou & Li, 2004
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publication ID |
https://doi.org/ 10.5281/zenodo.13244641 |
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persistent identifier |
https://treatment.plazi.org/id/28376877-A17E-FFB0-1B1D-FB05FDB14BBF |
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treatment provided by |
Felipe |
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scientific name |
Jesogammarus (Jesogammarus) fontanus |
| status |
sp. nov. |
Jesogammarus (Jesogammarus) fontanus View in CoL , new species
( Figs. 1-4 View Fig View Fig View Fig View Fig )
Material examined. – Holotype – male (IZCAS-I-A0085), 9.3 mm, Linfen City (36.05 oN, 111.31 oE), Shanxi Province, 28 Feb.1985.
Paratype – 1 female, same data as for holotype .
Diagnosis. – Peduncular article 1 of antenna 1 without posterodistal spine. Mandibular palp article 1 with three distal spines. Pleonites 1-3 without dorsomarginal spine. Outer ramus of uropod 2 with marginal spine. Uropod 3 foliaceous, inner ramus about one-forth of outer ramus. Telson longer than maximum basal width.
Description. – Male, body length 9.3 mm. Eyes medium in size and reniform ( Fig. 1A View Fig ). Antenna 1 ( Fig. 1E View Fig ) distinctly longer than antenna 2, peduncular articles 1-3 in length ratio 1: 0.71: 0.45, with some setae on posterior margins; flagellum with 28 articles, most with aesthetascs; accessory flagellum with five articles. Antenna 2 ( Fig. 1D View Fig ): peduncular article 4 about as long as article 5, both with short setae along posterior and anterior margins; flagellum with 13 articles, proximal 8 articles cup-calceolate.
Upper lip subrounded ( Fig. 1K View Fig ), with minute setae. Left mandible ( Fig. 1O View Fig ): incisor with five teeth; lacinia mobilis with five weak dentitions; molar with one seta; article 1 of palp with three spines on distal margin, article 2 with 12 marginal setae, nine submarginal setae and one pair of spines, article 3 about 83% of article 2 in length, with four A-setae, one group of 5 B-setae. Right mandible ( Fig. 1P View Fig ): incisor with four teeth; lacinia mobilis bifurcate. Lower lip ( Fig. 1J View Fig ): inner lobes absent. Maxilla 1 ( Figs. 1 View Fig L-N): inner plate with 17 plumose setae; outer plate with 11 serrated spines; article 2 of left palp with five apical spines accompanied by four setae and three setae on outer margin; article 2 of right palp with six apical stout spines accompanied by six setae and five setae on outer margin. Maxilla 2 ( Fig. 1I View Fig ): inner plate with 17 facial setae. Maxilliped ( Fig. 1Q View Fig ): inner plate with three apical stout spines, outer plate with a row of slender spines on medial margin and seven apical pectinate setae.
Coxal plate 1 weakly dilated distally ( Fig. 2A View Fig ), with two setae on postero-proximal margin, anterior corner with two setae, posterior corner with one stiff seta; coxal plates 2-3 subrectangular ( Figs. 2B View Fig , 3A View Fig ), posteroproximal margin bare; coxal plate 4 ( Fig. 3B View Fig ) excavated on posterior margin, with three spines; anterior lobe of coxal plates 5-6 ( Figs. 3C, D View Fig ) with one seta, posterior lobe with four setae; posterior margin of coxal plate 7 ( Fig. 3E View Fig ) with three setae. Coxal gills 2-5 ( Figs. 3 View Fig K-N) with two accessory lobes, accessory lobes of respective gills 2-4 subequal to each other, posterior lobe of gill 5 longer than anterior one; coxal gills 6-7 ( Figs. 3O, P View Fig ) with one accessory lobe.
Gnathopod 1 ( Figs. 2A, C, D View Fig ): basis with long setae on anterior and posterior margins; propodus broad, palm weakly oblique, with 13 and 10 peg spines on inner and outer margins, respectively; dactylus with one seta on outer margin. Gnathopod 2 ( Figs. 2B, E View Fig ): basis with longer setae on posterior margin than that of gnathopod 1; propodus more slender than that of gnathopod 1, with eight and seven peg spines on inner and outer palmar margins, respectively; dactylus with one seta on outer margin and one seta at hinge of nail.
Pereopods 3 and 4 similar ( Figs. 3A, B, F, G View Fig ). Bases with short setae on anterior margins and long setae on posterior margins, merus to propodus with slender spines and short setae on posterior margins, dactyli with one plumose seta on outer margin and one or two setae at hinge of nail.
Pereopods 6 and 7 longer than pereopod 5 ( Figs. 3 View Fig C-E, H- J). Bases with six to eight spines on anterior margins; posterior margin weakly concaved in pereopods 5 and 6, slightly expanded in pereopod 7, with a row of stiff setae; pereopods 6 and 7 with one spine on posterodistal corner. Merus and carpus with groups of spines along anterior and posterior margins. Dactyli with one plumose seta on outer margin and one seta at hinge of nail.
Pleonites 1-3 ( Fig. 1B View Fig ): posterodorsal margins with eleven, six and eight marginal setules, respectively. Epimeral plate 1 ( Fig. 1F View Fig ): lower margin horizontal, with 12 setae on anterior corner, posterodistal corner weakly acuminate, posterior margin with three setules; plate 2 ( Fig. 1G View Fig ) ventrally with four submarginal spines, posterior margin with two setules; plate 3 ( Fig. 1H View Fig ) with four spines on ventral margin, posterior margin with two setules. Pleopods 1-3 subequal in length ( Fig. 2I View Fig ), with dorsal and marginal setae, bearing two retinacula accompanied by three setae; inner ramus a little longer than outer ramus, both armed with plumose setae.
Urosomites 1-3 flat ( Fig. 1C View Fig ), urosomite 1 with two and three spines on dorsal margin, urosomite 2 with four evenly spaced spines, urosomite 3 with two spines laterally and two short setae medially. Uropod 1 ( Fig. 2G View Fig ): peduncle longer than both rami, with marginal spines and one basofacial spine; inner and outer ramus with two marginal spines, respectively. Uropod 2 ( Fig. 2H View Fig ): peduncle with three spines on each side, outer ramus with one spine on outer margin, inner ramus with two spines on outer margin. Uropod 3 ( Fig. 2F View Fig ): peduncle with seven distal spines; outer ramus foliaceous, with three groups of spines on outer margin, five groups of spines on inner margin accompanied by four plumose setae, terminal article about one-sixth of proximal article; inner ramus about one-fourth of outer ramus in length, with one spine and one plumose seta on outer margin.
Telson cleft ( Fig. 2J View Fig ), longer than maximum basal width, with one apical spine, left lobe with one distolateral spine.
Female – Body length 9.6 mm, ovigerous. Coxal plates 1-4 ( Figs. 4 View Fig A-D) with a row of setae on posteroproximal margins, inner faces with some long setae; coxal plates 5-7 ( Figs. 4 View Fig IK) with three to five long setae on lower margins.
Gnathopod 1 ( Fig. 4G View Fig ): propodus ovate, palm oblique, with nine simple spines on posterodistal corner. Gnathopod 2 ( Fig. 4H View Fig ): propodus subrectangular, with four simple spines on inner margin and three pectinate spines on outer margin. Bases of pereopods 5-7 ( Figs. 4 View Fig I-K) with a row of long setae on posterior margins, inner faces with groups of long setae, pereopod 6 with one slender spine on posterodistal corner, pereopod 7 with two spines on posterodistal corner. Oostegites 2-5 broad ( Fig. 4E View Fig ), with many marginal setae.
Etymology. – The epithet fontanus refers to the biotope.
Remarks. – Jesogammarus (J.) fontanus , new species, is very similar to Jesogammarus (J.) spinopalpus Morino, 1985 , in: (1) peduncular article 1 of antenna 1 without spine, (2) palp article 1 of mandible with three distal spines, (3) strong sexual dimorphism on the bases 5-7 and coxal plates 1-4, (4) uropod 2 with a marginal spine on outer ramus, and (5) elongate telson. The new species differs from J. (J.) spinopalpus by (1) medium sized eyes (small eyes in spinopalpus ), (2) urosomite 1 with two and four spines on posterodorsal margin (four singularly inserted spines in spinopalpus ), and (3) uropod 3 foliaceous (slender in spinopalpus ).
Jesogammarus (J.) fontanus is also similar to J. (J.) hinumensis Morino, 1993 in (1) weakly setose antenna 2, (2) spinose palp article 1 of mandible, (3) gills short accessory lobes and (4) setose pleonites. J. (J.) fontanus is distinguished from J. (J.) hinumensis by (1) medium sized eyes (large eyes in hinumensis ), (2) peduncular article 1 of antenna 1 without posterodistal spine (one spine in hinumensis ), (3) pleonites 1-3 with 8-12 setae (1-2 setose in hinumensis ), and (4) uropod 3 foliaceous (slender in hinumensis ), (5) pereopods of female with setation only in basis (basis to carpus setation in hinumensis ).
Habitat. – This new species is collected from a drinking well in Linfen City. The drinking well water temperature is between 4-7 C throughout the year.
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