Citation: Hershler R, Ratcliffe V, Liu H-P, Lang B, Hay C (2014) Taxonomic revision of the Pyrgulopsis gilae (Caenogastropoda, Hydrobiidae) species complex, with descriptions of two new species from the Gila River basin, New Mexico. ZooKeys 429: 69–85. doi: 10.3897/zookeys.429.7865
We describe two new species of springsnails (genus Pyrgulopsis) for populations from the middle Fork and upper East Fork of the Gila River Basin (New Mexico) that had been previously identified as P. gilae. We also restrict P. gilae to its originally circumscribed geographic range which consists of a short reach of the East Fork Gila River and a single spring along the Gila River (below the East Fork confluence). These three species form genetically distinct lineages that differ from each other by 3.9–6.3% for mtCOI and 3.7–8.7% for mtNDI (the latter data were newly obtained for this study), and are diagnosable by shell and penial characters. Collectively the three species form a strongly supported clade that is distinguished from other congeners by the unique presence of two glandular strips on the dorsal surface of the penial filament. These findings suggest that the conservation status of P. gilae, which was recently removed from the list of candidates for listing as endangered or threatened by the United States Fish and Wildlife Service, should be revisited and that the two new species may also merit protective measures given their narrow geographic ranges.
Gastropoda, United States, freshwater, taxonomy, conservation
Pyrgulopsis is a large genus (137 species;
Pyrgulopsis gilae (Taylor, 1987) was described for specimens from single springs along the lower East Fork (type locality) and main stem Gila River in Grant County, New Mexico. Field surveys in the 1990’s and 2000’s resulted in the discovery of new populations in two other reaches of the upper Gila River watershed (Middle Fork, upper East Fork) that are currently being treated as Pyrgulopsis gilae (
For the current molecular study we used the same samples that were analyzed in our previous phylogeographic investigation of Pyrgulopsis gilae across its entire geographic range (
The partition homogeneity/incongruence length difference test (
Genetic relatedness within Pyrgulopsis gilae was further assessed by a haplotype network that was generated by TCS version 1.21 using the default settings (e.g., 95% connection limit) and fixing the connection limit at 90 steps (
Types and other voucher material were deposited in the National Museum of Natural History (USNM) collection. Specimens of Pyrgulopsis gilae from the Bell Museum of Natural History (BellMNH) were also examined during the course of this study. Series of large adults (n>10) were used for shell measurements. Whorl counts refer to the entire shell. Sexual dimorphism in shells, which is occasionally observed in Pyrgulopsis (
We used a conservative, evolutionary lineage concept in describing new species only for those snails that are morphologically diagnosable as well as phylogenetically independent and substantially divergent genetically (
Map showing the distribution of mtDNA clades I-III.
Sample codes, collection localities, and GenBank accession numbers for Pyrgulopsis gilae mtDNA sequences.
Code | Locality (all in New Mexico) | COI | NDI |
---|---|---|---|
G1 | Spring along East Fork Gila River, ca. 1.53 km north, 2.9 km east of State Route 527 bridge crossing, Grant County | KC571284, KC571285 | KM079175, KM079176 |
G2 | Spring along East Fork Gila River, ca. 1.29 km north, 0.56 km west of Black Canyon confluence, Grant County | KC571286, KC571287 | KM079177, KM079178 |
G3 | Spring along East Fork Gila River, ca. 1.53 km north, 2.38 km east of State Route 527 bridge crossing, Grant County | KC571288, KC571289, KC571290 | KM079176 |
G4 | Seepage along Taylor Creek, ca. 0.32 km south, 0.93 km west of Wall Lake dam (below Wall Lake), Catron County | KC571291, KC571292, KC571293, KC571294 | KM079180 |
G5 | Hillside seep, 1.61 km north, 0.97 km east of Burnt Corral Canyon, Catron County | KC571295 | KM079181 |
G6 | Spring along Beaver Creek, ca. 0.29 km north, 0.40 km west of Taylor Creek confluence, Catron County | KC571296, KC571297, KC571298 | KM079181, KM079182 |
G7 | Seepage along Taylor Creek, 50 m west of Whitetail Canyon, Catron County | KC571292 | KM079183 |
G8 | Spring along Middle Fork Gila River, ca. 0.97 km north, 0.64 km west of Jordan Canyon, Grant County | KC571299, KC571300, KC571301, KC571302 | KM079187, KM079188 |
G9 | Fall Spring, 1.61 km north, 0.56 km east of Burnt Corral Canyon, Catron County | KC571303 KC571304 | KM079184, KM079185 |
†G10 | Fall Spring, 1.61 km north, 0.56 km east of Burnt Corral Canyon, Catron County | KC571304 | KM079185, KM079186 |
G11 | Spring along Middle Fork Gila River, ca. 0.48 km north, 0.48 km west of Jordan Canyon, Grant County | KC571305 | KM079187, KM079189, KM079190 |
G13 | Spring along Taylor Creek, 0.81 km north, 1.13 km east of Wall Lake Dam, Catron County | KC571292 | KM079183 |
G14 | “Alum Hot Spring, ” ca. 1.93 km south, 0.16 km west of State Route 527 bridge crossing, Grant County | KC571288, KC571306 | KM079179 |
†Very small (juvenile) specimens initially thought to be distinct from Pyrgulopsis gilae.
Sixteen (16) NDI haplotypes of Pyrgulopsis gilae were detected, 11 of which were restricted to single populations (Table 2). The others were shared by pairs of populations along the lower East Fork (haplotype II), upper East Fork (haplotypes VII, IX, XI) and Middle Fork (haplotype XIII) Gila River. Six (6) samples each contained a single haplotype (G3, G4, G5, G7, G13, G14). The TCS analyses (not shown) recovered three well differentiated haplotype groups composed of specimens from along the lower East Fork and main stem Gila River (clade I), Middle Fork Gila River (II), and the upper East Fork Gila River (III). These groups differed from each other by 3.7-8.7% sequence divergence; variation within groups was minor (Table 3). The AMOVA indicated that most of the detected variation (91.7%) was partitioned among these groups; variation within populations, and among populations within the groups was much smaller (1.35, 6.93%) but nonetheless was significant (Table 4). The three previously reported clades (I-III;
Holotype, USNM 1135068 (a dry shell), spring 0.48 km north, 0.48 km west of Jordan Canyon, Catron County, New Mexico, 33.2909°N, 108.2681°W, 1 October 2009, Michelle Christman. Paratypes, USNM 1231474 (from same lot).
NEW MEXICO. Catron County: USNM 1123432, USNM 1123588, spring 0.8 km north, 0.64 km west of Jordan Canyon (33.2889°N, 108.2683°W), USNM 1135067, spring 0.97 km north, 0.64 km west of Jordan Canyon (33.2924°N, 108.2696°W), USNM 883175, Jordan Hot Spring (33.2927°N, 108.2692°W).
Distinguished from Pyrgulopsis gilae and the species described next (Pyrgulopsis similis) by its narrower shell (mean shell width/shell height 0.613 vs. 0.682, t=-9.6588, df=36.2176, P<0.0001, n=30 for Pyrgulopsis gilae; 0.613 vs. 0.734, t=-16.3617, df=18.9656, P<0.0001, n=11 for Pyrgulopsis similis), more pronounced whorl shoulders, and broad overlap of the ventral surface of the penis by the terminal gland (probably reflecting fusion with a distal ventral gland). Further differs from Pyrgulopsis gilae in its smaller size (mean shell height 2.77 vs. 3.47 mm, t=-11.3848, df=21.9544, P<0.0001) and (basal) extension of the outer penial gland to mid-line or left edge of penis. Further differs from Pyrgulopsis similis in its larger size (mean shell height 2.77 vs. 2.36 mm, t=7.3691, df=15.3701, P<0.0001), smaller number of dorsal glands on the penis, and larger size of the terminal and ventral glands on the penis.
Shell (Fig. 3A–B) narrow-conic, whorls 4.5–5.0. Teleoconch whorls convex, shoulders narrow, angular, sutures impressed. Aperture ovate, angled above, parietal lip complete, usually slightly disjunct, umbilicus narrow. Outer lip thin, orthocline.
Operculum (Fig. 3C–D) as for genus; edges of last 0.5 whorl weakly frilled on outer side; portion of muscle attachment margin thickened on inner side. Radula (Fig. 3E–G) as for genus; dorsal edge of central teeth concave, lateral cusps four–five, basal cusp one. Lateral teeth having two–three cusps on both inner and outer sides. Inner marginal teeth with 14–20 cusps, outer marginal teeth with 17–22 cusps. Radula data are from USNM 1135067.
Penial filament and penial lobe about equal in length (Fig. 4A–B). Filament having two (penial) glands on dorsal surface; inner gland shorter. Outer penial gland curving to mid-line (10/24 specimens) or left edge of penis (14/24 specimens), the latter condition probably represents fusion with a gland on the left edge (Dg2). Terminal gland elongate, horizontal, broadly overlapping ventral surface of penis. Dorsal surface of penis having gland along right edge of lobe (Dg3) and 2-3 additional glands (22/24 specimens); one specimen did not have any additional glands and one specimen had four additional glands. Ventral gland positioned near centrally. Penial data are from USNM 1135067.
The specific epithet is a patronym honoring Marilyn Myers (United States Fish and Wildlife Service, retired) for her dedicated efforts to survey Pyrgulopsis habitats in the upper Gila River basin.
A series of seeps and springs along the north side of short reach (ca. 0.25 km) of the Middle Fork Gila River just below Jordan Hot Spring (Fig. 1). The type locality is a seep wall which is the lower-most occurrence of Pyrgulopsis marilynae along the Middle Fork Gila River; the water temperature at this site was 25°C on 1 October 2009.
Pyrgulopsis marilyane was resolved as sister to Pyrgulopsis gilae (100% posterior probability) in the molecular phylogenetic analysis (Fig. 2). The apparent fusion of the terminal and distal ventral glands of the penis that characterizes this species (in part) was previously reported for Pyrgulopsis sadai (
Frequency distribution of NDI haplotypes detected in Pyrgulopsis gilae. n=sample size.
Haplotype (specimen code) | Sample | ||||||||||||
G1 | G2 | G3 | G4 | G5 | G6 | G7 | G8 | G9 | G10 | G11 | G13 | G14 | |
I (G1A) | 2 | ||||||||||||
II (G1C) | 1 | 3 | |||||||||||
III (G2B) | 2 | ||||||||||||
IV (G2D) | 1 | ||||||||||||
V (G14B) | 4 | ||||||||||||
VI (G4B) | 3 | ||||||||||||
VII (G5A) | 4 | 1 | |||||||||||
VIII (G6B) | 4 | ||||||||||||
IX (G7A) | 8 | 4 | |||||||||||
X (G9A) | 2 | ||||||||||||
XI (G9C) | 2 | 2 | |||||||||||
XII (G10A) | 2 | ||||||||||||
XIII (G8A) | 5 | 1 | |||||||||||
XIV (G8D) | 1 | ||||||||||||
XV (G11F) | 2 | ||||||||||||
XVI (G11H) | 2 | ||||||||||||
n | 3 | 3 | 3 | 3 | 4 | 5 | 8 | 6 | 4 | 4 | 5 | 4 | 4 |
Mean NDI sequence divergence (maximum composite likelihood) within and among Pyrgulopsis gilae clades. I: G1, G2, G3, G14; II: G8, G11: III: G4, G5, G6, G7, G9 G10, G13.
Clade I | Clade II | Clade III | |
---|---|---|---|
Clade I | 0.003+/-0.002 | ||
Clade II | 0.037+/-0.011 | 0.002+/-0.001 | |
Clade III | 0.087+/-0.021 | 0.075+/-0.019 | 0.006+/-0.003 |
Genetic differentiation among Pyrgulopsis gilae clades based on NDI sequences. Sub-groups=(G1, G2, G3, G14), (G8, G11), and (G4, G5, G6, G7, G9, G10, G13). Asterisked Φ values are highly significant (P<0.001).
Source of variation | df | variance components | % of variation | Φ statistic |
---|---|---|---|---|
Among groups | 2 | 13.95 | 91.72 | 0.91* |
Among populations within groups | 10 | 1.05 | 6.93 | 0.84* |
Within populations | 43 | 0.21 | 1.35 | 0.99* |
Bayesian tree based on the combined (COI, NDI) dataset. Posterior probabilities for nodes are given when >95%. Specimen codes are from the Table 1.
Shells, opercula and radula, Pyrgulopsis marilynae n. sp. A Holotype, USNM 1135068 B Shell, USNM 1135067 C, D Opercula (outer, inner sides), USNM 1135067 E Portion of radular ribbon, USNM 1135067 F Central teeth, USNM 1135067 G Lateral and inner marginal teeth, USNM 1135067. Scale bars A, B 1.0 mm; C, D 100 µm; E 20 µm, F, G 10 µm.
United States: Holotype, USNM 1135064 (a dry shell), spring along Beaver Creek, ca. 0.29 km north and 0.4 km west of confluence with Taylor Creek, Catron County, New Mexico, 33.3405°N, 108.1097°W, 21 May 2009, BKL and Marilyn Myers. Paratypes, USNM 1135065, 1231475 (from same lot).
NEW MEXICO. Catron County: USNM 854684, USNM 1135057, USNM 1123589, USNM 1135058, USNM 1135059, Fall Spring, 1.61 km north, 0.56 km east of Burnt Corral Canyon (33.294°N, 108.1302°W), USNM 1123590, hillside seep 1.61 km north, 0.97 km east of Burnt Corral Canyon (33.2951°N, 108.1268°W), USNM 854685, USNM 1123594, USNM 1135060, USNM 1135061, seepage along Taylor Creek, ca. 0.32 km south, 0.93 km west of Wall Lake dam (33.3457°N, 108.0904°W), USNM 854683, USNM 1123592, USNM 1135062, USNM 1135063, spring along Taylor Creek, ca. 0.81 km north, 1.13 km east of Wall Lake Dam (33.3581°N, 108.0673°W), USNM 854682, USNM 1123593, NM: Catron Co., seepage along Taylor Creek, ca. 50 m west of Whitetail Canyon (33.3613°N, 108.0576°W).
Differs from Pyrgulopsis gilae in its smaller size (mean shell height 2.36 vs. 3.47 mm, t=--22.7297, df=36.4071, P<0.0001, n=30 for Pyrgulopsis gilae), larger number of glands on the dorsal surface of the penis, frequent extension of outer penial gland and/or Dg2 to the mid-line of the penis, and smaller size of the terminal and ventral glands on the penis. Contrasted with Pyrgulopsis similis above.
Shell (Fig. 5A–B) ovate- to narrow conic, whorls 3.75–4.50. Teleoconch whorls medium convex, narrowly shouldered. Aperture pyriform, parietal lip complete, usually adnate, sometimes slightly disjunct, umbilicus small. Outer lip thin, orthocline.
Operculum (Fig. 5C–D) as for genus; edges of last 0.5 whorl frilled on outer side; inner side near smooth. Radula (Fig. 5E–G) as for genus; dorsal edge of central teeth concave, lateral cusps four–six, basal cusp one. Lateral teeth having two–three cusps on inner sides and two–four cusps on outer sides. Inner marginal teeth with 15–20 cusps, outer marginal teeth with 16–25 cusps. Radula data are from USNM 1135059, USNM 1135064.
Penial filament longer than lobe (Fig. 4C–D). Filament having two (penial) glands on dorsal surface; inner gland shorter. Outer penial gland sometimes extending (basally) to mid-line (4/30 specimens) or left edge (7/30 specimens); Dg2 sometimes curving (basally) to mid-line (11/30 specimens). Terminal gland transverse, rather small. Dorsal surface of penis having gland along right edge of lobe (Dg3) and 3-7 additional glands (30/30 specimens) which form long, slightly oblique strips. Ventral gland small, positioned near centrally; second gland rarely present (4/30 specimens). Penial data are from USNM 1135065.
Springs along a short reach (ca. 10 km) of the East Fork Gila River from just above Wall Lake to slightly above the mouth of Burnt Corral Canyon (Fig. 1). The type locality is a spring brook (ca. one m wide and 0.25 m deep) that discharges at the base of the canyon wall along the east side of Beaver Creek; the water temperature at this locality was 22.1°C on 21 May 2009. The flow at this locality is augmented by numerous small seeps.
The specific epithet is an adjective referring to the close resemblance between this species and both Pyrgulopsis gilae and Pyrgulopsis marilynae.
Pyrgulopsis similis was resolved as sister to the clade composed of P. marilynae and Pyrgulopsis gilae (100% posterior probability) in the Bayesian analysis of molecular data (Fig. 2).
Shell parameters for Pyrgulopsis marilynae. Measurements are in mm.
WH | SH | SW | HBW | WBW | AH | AW | SW/SH | HBW/SH | AH/SH | |
---|---|---|---|---|---|---|---|---|---|---|
Holotype, USNM 1135068 | ||||||||||
4.75 | 2.99 | 1.78 | 2.12 | 1.56 | 1.22 | 1.15 | 0.60 | 0.71 | 0.41 | |
USNM 12231474 (n=10) | ||||||||||
Mean | 4.60 | 2.77 | 1.70 | 2.01 | 1.51 | 1.16 | 1.6 | 0.61 | 0.73 | 0.42 |
S.D. | 0.13 | 0.15 | 0.08 | 0.10 | 0.07 | 0.05 | 0.05 | 0.01 | 0.02 | 0.0 |
Range | 4.50–4.75 | 2.51–3.06 | 1.53–1.83 | 1.83–2.15 | 1.37–1.62 | 1.04–1.22 | 0.95–1.12 | 0.60–0.64 | 0.69–0.76 | 0.40–0.44 |
Penes (dorsal, ventral surfaces). A, B Pyrgulopsis marilynae n. sp., USNM 883175 C, D Pyrgulopsis similis n. sp., USNM 1135065 E, F Pyrgulopsis gilae, BellMNH 20898. Scale bars A–F 200 µm. Dg2 dorsal gland along left edge Dg3 dorsal gland along right distal edge Ipg inner (left) penial gland Opg outer (right) penial gland Tg terminal gland Vg ventral gland.
Shells, opercula and radula, Pyrgulopsis similis n. sp. A Holotype, USNM 1135064 B Shell, USNM 854684 C, D Opercula (outer, inner sides), USNM 1135065 E Portion of radular ribbon, USNM 1135065 F Central teeth, USNM 1135065 G Lateral and inner marginal teeth, USNM 1135065. Scale bars A, B 1.0 mm; C, D 200 µm; E 20 µm, F, G 10 µm.
Holotype, LACM 2214; paratypes, BellMNH 20898, BellMNH uncat., UTEP 10054, USNM 854087 (from same lot as holotype).
NEW MEXICO. Grant County: USNM 1135050, USNM 1135052, spring ca. 1.29 km mile north, 0.55 km west of confluence of East Fork Gila River and Black Canyon (33.1864°N, 108.1675°W), USNSM 1123426, USNM 1135055, USNM 1135056, spring ca. 1.53 km north, 2.38 km east of State Route 527 bridge crossing (33.1946°N, 108.1804°W).
NEW MEXICO. Grant County: topotypes, USNM 1004620, USNM 1135043, USNM 1135044, spring ca. 1.53 km north, 2.90 km east of State Route 527 bridge crossing (33.1917°N, 108.1742°W), BellMNH uncat., USNM 873211, USNM 1068942, “Alum Hot Spring, ” ca. 1.93 km south, 0.16 km west of State Route 527 bridge crossing (33.1618°N, 108.2081°W).
Several groups of springs in the lower reach of the East Fork Gila River (below the mouth of Black Canyon) and a single spring along the Gila River ca. 2 km below the East Fork confluence (Fig. 1).
Examination of the large series of penes that Taylor scored for this species (BellMNH 20898, BellMNH uncat.) indicated that neither the outer penial gland nor Dg2 extends appreciably onto the dorsal surface of the penis (Fig. 4E–F; also see
Shell parameters for Pyrgulopsis similis. Measurements are in mm.
WH | SH | SW | HBW | WBW | AH | AW | SW/SH | HBW/SH | AH/SH | |
---|---|---|---|---|---|---|---|---|---|---|
Holotype, USNM 1135064 | ||||||||||
4.25 | 2.52 | 1.73 | 1.94 | 1.48 | 1.24 | 1.10 | 0.69 | 0.77 | 0.49 | |
USNM 1231475 (n=11) | ||||||||||
Mean | 4.05 | 2.36 | 1.73 | 1.89 | 1.50 | 1.22 | 1.04 | 0.73 | 0.80 | 0.52 |
S.D. | 0.10 | 0.10 | 0.09 | 0.07 | 0.07 | 0.06 | 0.04 | 0.02 | 0.02 | 0.02 |
Range | 4.00–4.25 | 2.16–2.50 | 1.62–1.89 | 1.78–2.01 | 1.41–1.61 | 1.14–1.30 | 0.98–1.09 | 0.71–0.76 | 0.78–0.83 | 0.49–0.55 |
Shells, Pyrgulopsis gilae. A USNM 1135052 B USNM 854574. Scale bars A, B, 1.0 mm.
The results of this study provide additional evidence that the current taxonomy of Pyrgulopsis in some cases masks cryptic species diversity. Our previous revision of widely ranging Pyrgulopsis micrococcus revealed this taxon to be a polyphyletic composite of five species, three of which were undescribed (
The delineation of cryptic species complexes often has important consequences for conservation (
Our findings also underscore the need for additional field surveys to further delineate the occurrences of Pyrgulopsis in New Mexico and to supplement the recent monograph by
We thank Andrew Simons and Jonathan Slaght (BellMNH) for loan of specimens under their care. Marilyn Myers and Michelle Christman assisted with fieldwork; the former also shared her field notes. Yolanda Villacampa measured shells and prepared scanning electron micrographs, and Freya Goetz inked the anatomical drawings. This project was supported by awards (to RH) from New Mexico Department of Game and Fish (Contracts # 10-516-0000-00010, 14-516-000-00017) and Section 6 funding (Grant E-54) from the USFWS.
Appendix 1
Authors: Robert Hershler, Victoria Ratcliffe, Hsiu-Ping Liu, Brian Lang, Claire Hay
Data type: specimens data.
Explanation note: GenBank accession numbers for outgroup mtDNA sequences.
Copyright notice: This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
Link: doi: 10.3897/zookeys.429.7865.app1