Pacificabathynella kalispellensis, Camacho & Newell & Reid, 2009
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https://doi.org/ 10.1080/00222930903015832 |
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https://treatment.plazi.org/id/3C3587A4-FF84-FFB5-FE3A-D72275AEFD23 |
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treatment provided by |
Felipe |
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scientific name |
Pacificabathynella kalispellensis |
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sp. nov. |
Pacificabathynella kalispellensis sp. nov.
( Figures 1–3 View Figure 1 View Figure 2 View Figure 3 )
Material examined
Type locality. Flathead County, St-SR-well, 31 May 1989 (one male, holotype), Montana, USA. Others localities: Flathead County , well station SR, 2 April 1989 (two male and three female were collected; one female is the allotype); Flathead County , Middle Fork , Nyack , Chris B well, 20 February 2004 (two males and two females) ; Montana. Flathead County, Middle Fork , Nyack , Tadpole B well, 30 April 2004 (six females and one juvenile) , Montana, USA (see Table 2). The details of the description are based on all specimens. The holotype is a male and the allotype is a female and the type series contains 14 additional specimens (four males and 10 females) . (Holotype MNCN20.04 View Materials /8090, Allotype MNCN20.04 View Materials /8091 and type series MNCN20.04 View Materials /8092.)
Description
Body. Total length of holotype (male) 1.01 mm and allotype (female) 1.41 mm. Largest male total length 1.47 mm, smallest 1.01 mm; largest female total length 1.44 mm, smallest 1.30 mm. For variability see Table 4. Body form not very elongated, almost cylindrical, approximately 12 times as long as wide. Pleotelson with one barbed dorsal seta on either side, shorter than furcal rami.
Antennule ( Figure 1A View Figure 1 ). Seven segments; length of first three segments similar to other four segments; segments four and five smaller than others; segment four half length of segment five; setation as in Figure 1 View Figure 1 (A); three aesthetascs on sixth and seventh segments. A.I shorter than A.II, as long as the last five segments of A.II combined.
Antenna ( Figure 1B View Figure 1 ). Almost 25% longer than A.I; first four segments almost twice as long as last three; three terminal segments similar in length; fourth segment very elongated, twice length of fifth segment, with 12 setae; setal formula: 0/2+exp/3+0/ 12+0/5+1/4+4/5; exopod with two terminal setae, one of these a bifurcated sensory seta; ventromedial seta absent.
Paragnath ( Figure 1C View Figure 1 ). Large, with rounded distal part and very thick setulation on all surfaces in distal half.
Mandible ( Figure 1D,E View Figure 1 ). Palp with three segments, terminal segment with two long barbed claws, second segment as long as terminal segment, more or less cylindrical without expansions. Incisor process (pars incisiva) with two teeth; processus incisivus accessorius with one tooth and one long seta-like tooth; pars molaris with two dentate structures, like two crowns ( Figure 1E View Figure 1 ) parallel to main axis of teeth, the first with consistently strong denticles and the other with small denticles, except the most distal which is a strong tooth.
Maxillule ( Figure 1F View Figure 1 ). Proximal endite with four setae; distal endite with six teeth, four with spines (denticles) and two more seta-like, with three plumose setae and tufts of long setules on outer margin.
Maxilla ( Figure 1G View Figure 1 ). Four segments; setal formula 7, 4, 7, 6.
Thoracopods I to VII ( Figures 2A–F View Figure 2 , 3F,G View Figure 3 ). Sexual dimorphism present in Th. VI. Th. I ( Figure 2A View Figure 2 ) smaller than others; Th. II ( Figure 2B View Figure 2 ) to V ( Figure 2E View Figure 2 ) similar in size and Th. VI ( Figure 3G View Figure 3 ) and VII ( Figure 2F View Figure 2 ) longer than others. Th. I without epipod; coxa with a long and strong plumose seta; basipod with three plumose setae. Exopod with one segment on all thoracopods, shorter than endopod in all cases; with six barbed setae, two terminal, one dorsal and three ventral. Endopod with four segments in all thoracopods, setal formulae (number of setae on basipod in brackets):
Th. I: (3) 6+0/9+1/11+0/7
Th. II: (5) 5+0/7+1/6+0/6
P. sequoiae P. kalispellensis sp. nov. P. stanfordi sp. nov. P. ruthae sp. nov.
A.II: setal formula 0/2/2/2/0/3/5 0/2/3/12/6/8/5 0/2/2/2/0/4/5
A.I/A.II A.I<A.II A.I<A.II A.I<A.II Mx.II: setal formula 7/4/7/5 7/4/7/6 7/4/7/5 Epipod of Th. I absent absent absent Epipod of Th. II absent present absent Exopod of Th.I 5 setae 6 setae 5 setae Exopod of Th. II to VII 6 setae 6 setae 5 setae Th VIII female exp.>>endp. exp.>>endp. exp.>endp
Size of epipod 2 times bsp 3 times bsp 2 times bsp
Setae coxa 2 plumose 2 plumose 1 plumose
Seta basipod 1 smooth 1 plumose 1 smooth
Number setae exp. 2 smooth 3 smooth 2 smooth
Number setae endp. 2 smooth 2 barbed 2 smooth 0/2/2/2/0/4/5 A.I=A.II 7/4/7/5 absent absent
6 setae
6 setae exp.>endp 1.5 times bsp 1 plumose
1 smooth
2 smooth
2 smooth
Th VIII male: Bsp.: setae 2 1
Exp.: long/width (setae) 3 times (5) 2 times (4) 2 times (5) Endopod: setae 1+1 1 1
Crt. Basipod not pronounced very pronounced very pronounced
Pleopod: setae 1/– 1/7 1/6
Uropod: Sympod: spines 8 8 6
Endp.: spines 4 8 5
Endp./symp. Symp.>endp. Symp.<endp. Symp.>endp.
Exp. setae 8 8 7
Exp./endp. Exp.<endp. Exp.<endp. Exp.<endp.
Furca: first spines /second 3 times longer 2.3 times longer 1.3 times longer first spines/dorsal 7 times longer 2 times longer 2 times longer
size spines DS<S1>S2=S3>S4 S1>DS>S2=S3>S4 S1>DS>S2>S3>S 4 Males: Min.–Max. length 1.32 0.95–1.42 0.53–1.02
Females: Min.–Max. length 1.27 0.84–1.46 0.51–0.94
2
3 times (5)
1
pronounced
1/7
6
6
Symp.>endp.
9
Exp.<endp.
1.5 times longer
2 times longer S1>DS>S2=S3> S4 1.57 –2.07 1.45–1.78
Abbreviations: A.I, antennule; A.II, Antenna; bsp., basipod; Crt., crest of the basipod; endp., endopod; exp., exopod; segs., segments; DS, dorsal spine of the furca; S1, spine 1 of the furca; S2, spine 2 of the furca; S3, spine 3 of the furca; S5, spine 5 of the furca.
Th. III: (5) 5+0/7+1/5+0/6
Th. IV: (5) 4+0/5+1/5+0/5
Th. V: (3) 3+0/3+1/4+0/4
Th. VI: (0) 1+0/0+1/2(1)
Th. VII: (1) 1+0/0+1/0+0/2(1)
Thoracopod VI ( Figure 3G View Figure 3 ) with aberrant structure, with only three segments in endopod: first segment broader than usual, second segment broad and dilated bearing on its outer margin strong medially curved seta, third segment small with two setae, one long and another shorter.
Coxa of Th. II–VI with oblique row of tiny spinules on inner margin; basipods of Th. I–III and Th. VII have tufts of long fine setules.
Male thoracopod VIII ( Figure 3A,B View Figure 3 ). Longitudinal axis of coxa and basipod form 25° angle. Penial region with frontal lobe, inner lobe, outer lobe. Frontal lobe with lobules on distal end, almost completely covers outer and inner lobes. Inner lobe more or less similarly developed to frontal lobe, distal region divided into three areas with conical projection on internal side. Outer lobe smallest with two almost cylindrical lobules. Basipod very large, with distal, very well-developed, crest-like protuberance with rows of setules distally on inner side and with one lateral-distal barbed seta. Endopod one-segmented, small, half length of exopod, one distal seta. Exopod well developed with five setae.
First pleopods ( Figure 3C View Figure 3 ). Two segments, first segment with one very long seta; second segment with seven setae.
Female thoracopod VIII of the allotype ( Figure 3D View Figure 3 ). Coxa with two small, barbed lateral setae; very large epipod, three times length of basipod; endopod onesegmented, with two apical barbed setae of equal length; exopod slightly more slender, a little longer than endopod, with three apical smooth setae of similar length.
Female thoracopod VI of the allotype ( Figure 3H View Figure 3 ). Exopod one-segmented and with six setae, as in other thoracopods; endopod four-segmented, setal formula 1+0/0+1/ 0+0/2(1). Number of setae on segments of endopod and basipod of thoracopods differs between female and male. Setal formulae of allotype (number of setae of basipod in brackets):
Th. I: (4) 8+0/8+1/11+0/7
Th. II: (8) 7+0/7+1/8+0/7
Th. III: (7) 7+0/8+1/7+0/7
Th. IV: (6) 6+0/7+1/7+0/6
Th. V: (6) 3+0/4+1/5+0/5
Th. VI: (1) 1+0/0+1/0+0/2(1)
Th. VII: (1) 1+0/0+1/0+0/2(1)
Uropods ( Figure 3E View Figure 3 ). Sympod slightly shorter than endopod, 1.5 times longer than wide, with eight distal equal spines; endopod 30% longer than exopod, with eight strong claws, distal two longest, most distal eight times length of two most basal, terminally with two very long setae and two shorter setae located dorsolaterally, all barbed; exopod with eight setae, two terminal, three medial and three basal. Endopod with spinous projection at the distal outer corner.
Furcal rami ( Figure 3F View Figure 3 ). Almost square, bearing five spines; dorsal spine almost 50% length of second spine, second spine twice length of two medial spines, medial spines twice length of fifth spine.
Variability
The observed variability affects the number of setae of the two last segments of the antenna with six, seven or eight and four or five, respectively) and the numbers of setae of the different segments of the endopods of thoracopods I to IV on males and thoracopods I to V on females (see Table 5).
The setal formula on the males different from the holotype is:
Th. I: 6–8+0/8+1/8–9+0/6–7
Th. II: 6+0/6+1/6–8+0/6
Th. III: 6+0/6+1/6+0/5–6
Th. IV: 4–5+0/5–6+1/5+0/5
The setal formula on females different from the setal formula of the allotype is:
Th. I: 8–10+0/9–10+1/9–11+0/8
Th. II: 8+0/7+1/6+0/6–10
Th. III: 6+0/6–7+1/7+0/6–7
Th. IV: 5–6+0/5–6+1/6+0/5–6
Th. V: 3–4+0/4–5+1/4–5+0/5
Etymology
The species name is taken from the name of the nearby city of Kalispell and the aquifer containing this new species.
Remarks
Pacificabathynella kalispellensis sp. nov. is similar in size to P. sequoiae , and is the second largest of the four known species. It has a profusion of setae on the antenna and on the thoracopods (see Table 5 and Figures 1B View Figure 1 , Figure 2A–E View Figure 2 ). The antenna is 25% longer than the antennule. This is the species with the highest number of unique characters within the genus. The setal formula of the antenna ( Figure 1B View Figure 1 ) is unique to the genus (see Table 3) and to the family Bathynellidae ; the fourth segment is very long and has many setae; segment five is well developed and has six setae, whereas normally in this family this segment lacks setae. The pars molaris of the mandible has more teeth than in other species. On the fourth segment of the maxilla there are six setae, whereas all the other species of the genus have only five. The epipod of thoracopod II ( Figure 2B View Figure 2 ) is absent in other species. The setal formula of the endopod of the thoracopods is unique (see Table 5). The male thoracopod VIII is very large and massive and the crest of the basipod ( Figure 3B View Figure 3 ) is better developed than in the four other species of the genus, has setulae and only one plumose seta. The epipod of thoracopod VIII of the female is very large ( Figure 3D View Figure 3 ), three times the length of the basipod; the exopod has three smooth setae (two is the norm) and the seta of the basipod is plumose. This species has the highest number of spines on the endopod of the uropod (eight) and the endopod of the uropod is longer than the sympod whereas the opposite is the norm in the genus.
Pacificabathynella kalispellensis sp. nov., despite being a species with many unique characters, is perhaps the species that has most in common, apart from size, with P. sequoiae (see Table 3). On the uropod, both species have eight spines on the sympod and eight setae on the exopod, although they differ in the endopod, the new species having twice the number of spines as P. sequoia . The furca is similar in both species, one spine is longer than the other, but the dorsal spine is longest in the new species, while in P. sequoiae it is very small; in the other two species all furcal spines are very similar. The oblique row of tiny spinules on the inner margin of the coxa of thoracopods II–VI is unique. Schminke and Noodt (1988) in the original description of P. sequoiae drew something similar in the coxa of thoracopod VII (figure 28, p. 296), but did not comment on the structure. Thoracopod VIII of the male is very different for both species.
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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