Research Article |
Corresponding author: Marshal Hedin ( mhedin@sdsu.edu ) Academic editor: Cristina Rheims
© 2022 Erik Ciaccio, Andrew Debray, Marshal Hedin.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ciaccio E, Debray A, Hedin M (2022) Phylogenomics of paleoendemic lampshade spiders (Araneae, Hypochilidae, Hypochilus), with the description of a new species from montane California. ZooKeys 1086: 163-204. https://doi.org/10.3897/zookeys.1086.77190
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Hypochilus is a relictual lineage of Nearctic spiders distributed disjunctly across the United States in three montane regions (California, southern Rocky Mountains, southern Appalachia). Phylogenetic resolution of species relationships in Hypochilus has been challenging, and conserved morphology coupled with extreme genetic divergence has led to uncertain species limits in some complexes. Here, Hypochilus interspecies relationships have been reconstructed and cryptic speciation more critically evaluated using a combination of ultraconserved elements, mitochondrial CO1 by-catch, and morphology. Phylogenomic data strongly support the monophyly of regional clades and support a ((California, Appalachia), southern Rocky Mountains) topology. In Appalachia, five species are resolved as four lineages (H. thorelli Marx, 1888 and H. coylei Platnick, 1987 are clearly sister taxa), but the interrelationships of these four lineages remain unresolved. The Appalachian species H. pococki Platnick, 1987 is recovered as monophyletic but is highly genetically structured at the nuclear level. While algorithmic analyses of nuclear data indicate many species (e.g., all H. pococki populations as species), male morphology instead reveals striking stasis. Within the California clade, nuclear and mitochondrial lineages of H. petrunkevitchi Gertsch, 1958 correspond directly to drainage basins of the southern Sierra Nevada, with H. bernardino Catley, 1994 nested within H. petrunkevitchi and sister to the southernmost basin populations. Combining nuclear, mitochondrial, geographical, and morphological evidence a new species from the Tule River and Cedar Creek drainages is described, Hypochilus xomote sp. nov. We also emphasize the conservation issues that face several microendemic, habitat-specialized species in this remarkable genus.
Conservation, mountains, multispecies coalescent, short-range endemism, Sierra Nevada, southern Appalachians, taxonomic over-splitting, ultraconserved elements
Discovering and delimiting cryptic species boundaries is, almost by definition, challenging. When the multispecies coalescent (MSC) is applied to species delimitation, species boundaries are explored by estimating gene trees and accounting for species tree/gene tree discordance using MSC models. Critical to this approach is discerning the boundary between population-level versus species-level divergence, as a core assumption of most MSC models is that species are panmictic and without population structure (
Population genetic structuring is rather ubiquitous in nature. Species with strict or semi-strict habitat or microhabitat preferences will naturally occur discontinuously over a landscape. Combine this natural habitat fragmentation with limited dispersal ability, and populations will evolve to be genetically different, to various degrees (
The spider genus Hypochilus Marx, 1888 represents a challenging system for species delimitation, combining allopatric geographic distributions, morphological conservatism, and high genetic structuring. Hypochilus is a Nearctic genus representing one of two described genera in the family Hypochilidae, a family of true spiders which retain many interesting plesiomorphic traits (
Distribution of the three geographic groups of Hypochilus in the mountains of California, the Rocky Mountains, and the southern Appalachians. Regional insets show the sampling locations of forty-three Hypochilus specimens used in genetic analyses; Appalachian species represented by different symbols.
As spiders with extraordinarily low vagility, one would expect deeper phylogenetic relationships in Hypochilus to closely mirror geography, with phylogenetic predictions following geography. However, previous studies have suggested that this may be an oversimplification. Both morphological and mitochondrial data suggest that the geographically separated California and Appalachian mountain faunas are sister lineages (
As commonly found in SRE taxa, prior intraspecific genetic research in Hypochilus has revealed ubiquitous and extensive genetic structuring. In Appalachia, extreme mitochondrial genetic divergence occurs within and among five described species over small geographic distances (
In this research we used phylogenomic data to resolve Hypochilus species relationships within and among montane regions. We also explored putative cryptic diversification within Appalachian H. pococki and Californian H. petrunkevitchi. In Appalachia, previous mitochondrial-based species delimitation using a Generalized Mixed Yule Coalescent (GMYC) model (
Specimens representing the genus Ectatosticta Simon, 1892 from China, the sister genus to Hypochilus (and the only other hypochilid genus described), were used to root all phylogenies (UCE data from
For almost all specimens (with tissues stored at -80 °C), DNA extraction was performed using a Qiagen DNEasy kit from leg tissues. Sequence capture libraries were prepared using an ultraconserved elements capture protocol for arachnids (
A 50 percent occupancy matrix (623 loci) was generated from the pipeline above (here called the “unfiltered” matrix). A second matrix was further filtered to remove duplicate and potentially non-homologous sequences. Previous work has shown that arthropod UCEs are mostly located within exonic regions (
Interspecific relationships were reconstructed using all three UCE data matrices (“unfiltered”, “filtered”, and “filtered and trimmed”), utilizing both concatenation and coalescent-model approaches. Data were partitioned by locus, with optimal models selected using PartitionFinder2 (
Nuclear single nucleotide polymorphism (SNP) data were extracted from UCE loci following the methods of
Using multiple data sources (phylogenomic results, STRUCTURE results, geography for H. petrunkevitchi, and mitochondrial haplogroup membership for H. pococki), alternative species models were generated and compared using nuclear SNP datasets in the program SNAPP (Tables
Alternative species model comparison results for H. petrunkevitchi, from SNAPP. Alternative models were compared to current taxonomy and ranked with 1 as the most favorable and 5 as the least. Bayes factors were calculated as (BF = 2 × (model 1 – model 2)) where negative values represent support for model 2 (alternative model) and positive values are support for the null model (current taxonomy).
Model | Species | Partitioning | MLE | MLE 2 | BF | Rank |
---|---|---|---|---|---|---|
Every Tip | 16 | Every specimen as a species | -105 | -105.2 | -7056 | 1 |
Basins | 8 | H. kastoni, H. bernardino, CEDAR, TULE, KAW, KING, SAN, YOSE | -1781 | -1781 | -3704 | 2 |
STRUCTURE | 6 | H. kastoni, H. bernardino, TULE+CEDAR, KAW+KING, SAN, YOSE | -1939 | -1939 | -3388 | 3 |
Current Taxonomy | 3 | H. kastoni, H. petrunkevitchi, H. bernardino | -3633 | -3633 | - | 4 |
Collapse | 2 | H. kastoni, H. petrunkevitchi + H. bernardino | -4223 | -4223 | 1180 | 5 |
A rooted triplet species delimitation approach was also implemented using the Python2 compatible version of the program TR2 (
SNAPP results for H. pococki. Models were compared to current taxonomy and ranked with 1 as the most favorable and 4 as the least.
Model | Species | Partitioning | MLE | MLE 2 | BF | Rank |
---|---|---|---|---|---|---|
Every Tip | 16 | Every specimen as a species | -62.9 | -62.8 | -5030 | 1 |
Mitochondrial | 6 | H. thorelli, WEST+bone+alark, CENT, VA, ELK, NE | -3917 | -3917 | -4462 | 2 |
STRUCTURE | 5 | H. thorelli, WEST+bone+alark, CENT, ELK+NE, VA | -4338 | -4340 | -3620 | 3 |
Current Taxonomy | 2 | H. thorelli, H. pococki | -6148.9 | -6148 | - | 4 |
Mitochondrial Cytochrome c oxidase subunit I (CO1) data for the California taxa were captured from UCE “by-catch” for purposes of phylogenetic and distance analyses, particularly considering the extreme CO1 distances observed in
A Generalized Mixed Yule Coalescent (GMYC) model was used to algorithmically delimit Californian species using CO1 data, in a manner similar to the approach of
Although Hypochilus is a strongly morphologically conserved genus, current species were described and are diagnosed using subtle morphological variation, mostly in male genitalia (
For taxonomic descriptions, morphological measurement details follow
PTW/PTL maximum width of male pedipalpal tibia in retrolateral view/length of tibia in retrolateral view;
CdL male palpal conductor length in retrolateral view;
AME diameter of anterior median eye pupil;
PTaL length of male palpal tarsus in retrolateral view;
CTpr number of promarginal cheliceral teeth;
CTre number of retromarginal cheliceral teeth.
Measurements were taken from alcohol-preserved specimens using an Olympus SZ40 dissecting microscope fitted with an ocular micrometer, and converted to millimeters; raw measurements are provided in Suppl. material
Original UCE raw reads have been submitted to the SRA (PRJNA760946), with summary statistics presented in the Suppl. material
Concatenated ML and SVDquartets analyses of the above three matrices recover nearly identical Hypochilus relationships, except for some nodes in the Appalachian and Rocky Mountain clades (Figs
UCE phylogeny. Phylogeny reconstructed from partitioned RAxML analysis of “filtered and trimmed” UCE matrix. Bootstrap support values are 100 for all nodes unless otherwise indicated; second support values from IQ-TREE. Inset – SVDquartets UCE tree with bootstrap support values less than 95 shown.
Concordance Factor values. Phylogeny reconstructed from partitioned RAxML analysis of “filtered and trimmed” UCE matrix, with gCF / sCF values. The lowest gCF and sCF values, for two unresolved nodes which collapse to a four lineage polytomy within the Appalachian clade, are highlighted by red text.
Nuclear SNP datasets included 670 unlinked SNPs for the California sample (allowing 20% missing data) and 655 unlinked SNPs for the Appalachian sample (19% missing data). Overall, STRUCTURE analyses reveal strong population structure for both samples, with inferred genetic clusters congruent with phylogenomic clades (Fig.
There is more evidence for mixed ancestry in H. pococki STRUCTURE analyses, using a best K from both Pritchard (K = 4) and Evanno (K = 3) methods. The Elk and Northeast “microclades” (ELK and NE) are lumped as a single genetic population, while one member from the mitochondrial Central (CENT) group clusters with the WEST population (Fig.
Alternative species hypothesis models were generated and compared using SNAPP and TR2 for both H. petrunkevitchi (five models) and H. pococki (four models). Pritchard-based best K schemes were used for the STRUCTURE derived species models. The most-favored SNAPP model for H. petrunkevitchi (Table
TR2 results for H. petrunkevitchi; ranking of the models with 1 being the most favored and 6 being the least favored.
Model | Species | Partitioning | Score | Rank |
---|---|---|---|---|
Every Tip | 16 | Every specimen as a species | 171.62 | 1 |
Basins | 8 | H. kastoni, H. bernardino, TULE, CEDAR, KAW, KING, SAN, YOSE | 213.95 | 2 |
STRUCTURE | 6 | H. kastoni, H. bernardino, TULE+CEDAR, KAW+KING, YOSE, SAN | 348.23 | 3 |
Current Taxonomy | 3 | H. kastoni, H. petrunkevitchi, H. bernardino | 9334.94 | 4 |
Collapse | 2 | H. kastoni, H. petrunkevitchi + H. bernardino | 25926.79 | 5 |
One species | 1 | H. kastoni + H. petrunkevitchi + H. bernardino | 30938.48 | 6 |
The CO1 by-catch phylogeny, using H. kastoni and H. bernardino as possible outgroups, shows strong support (BP = 100) for a clade including H. bernardino and H. petrunkevitchi together (Fig.
TR2 results for H. pococki; ranking of the models with 1 being the most favored and 5 being the least favored.
Model | Species | Partitioning | score | Rank |
---|---|---|---|---|
Every Tip | 16 | Every specimen as a species | 344.10 | 1 |
Mitochondrial | 7 (*includes BONE as separate lineage) | H. thorelli, WEST, CENT, ELK, NE, VA, BONE | 366.66 | 2 |
STRUCTURE | 5 | H. thorelli, WEST+Bone+Alark, CENT, ELK+NE, VA | 819.85 | 3 |
Current | 2 | H. thorelli, H. pococki | 9930.73 | 4 |
Collapse | 1 | H. thorelli + H. pococki | 17961.09 | 5 |
Maximum likelihood mitochondrial tree. Black circles designate clusters of sequences collapsed as the same species in multi-threshold GMYC analyses; all other branches supported as separate species (e.g., n = 13 for multi-threshold model). Inset – K2P distances within and among primary mitochondrial lineages.
Morphological data for H. pococki and California taxa are presented below in the Discussion and Taxonomy sections, respectively.
Our results confirm the
We hypothesize that Hypochilus has a more ancient history, and that this timing difference might also explain the unique phylogenetic topology seen in Hypochilus. Divergence time estimates for Hypochilus are hindered by a lack of direct fossil evidence, with current age estimates for the genus derived from broader examinations of diversification dates for spiders. For example, using published transcriptome data,
Hypothesized Cretaceous-age divergences for Hypochilus are complicated by the presence of the Western Interior Seaway of North America, a major transcontinental marine barrier in place from ~ 105–65 mya (
Within Appalachia, nuclear UCE data strongly support a monophyletic H. pococki, contra mitochondrial paraphyly as in
Nuclear STRUCTURE results confirm distinct genetic groups within H. pococki (Fig.
Although SNAPP and TR2 show higher support for increasing species numbers within H. pococki (i.e., a many species hypothesis), nuclear STRUCTURE results and consideration of male pedipalp morphology suggest more conservative species numbers. In their diagnosis,
H. pococki male palp (conductor) comparison. For each specimen, left panel = prolateral view, right panel = retrolateral view. NE lineage A, B Green Mtn (MCH 01_162) C, D Boone Fork (MCH 01_159); ELK lineage E, F Elk River (MCH 01_155) G, H Linville Gorge (MCH 01_165). Shorter secondary coil for ELK specimens highlighted by arrows; VA lineage I, J Cliff Mtn (MCH 04_028) K, L Guest River (MCH 04_027); CENT lineage M, N Hickory (MCH 01_144) O, P Wagon Road Gap (MCH 01_181); WEST lineage Q, R Alarka (MCH 02_168) S, T Starr Mtn (MCH 02_156) U, V Backbone Rock (MCH 04_025) W, X Chunky Gal Mtn (MCH 02_142). Detailed specimen information provided in Suppl. material
H. pococki male palp comparison, prolateral views. NE lineage A Green Mtn (MCH 01_162) B Boone Fork (MCH 01_159); ELK lineage C Elk River (MCH 01_155) D Linville Gorge (MCH 01_165); VA lineage E Cliff Mtn (MCH 04_028) F Guest River (MCH 04_027); CENT lineage G Hickory (MCH 01_144) H Wagon Road Gap (MCH 01_181); WEST lineage I Alarka (MCH 02_168) J Starr Mtn (MCH 02_156) K Backbone Rock (MCH 04_025) L Chunky Gal Mtn (MCH 02_142). Detailed specimen information provided in Suppl. material
H. pococki male palp comparison, retrolateral views. NE lineage A Green Mtn (MCH 01_162) B Boone Fork (MCH 01_159); ELK lineage C Elk River (MCH 01_155) D Linville Gorge (MCH 01_165); VA lineage E Cliff Mtn (MCH 04_028) F Guest River (MCH 04_027); CENT lineage G Hickory (MCH 01_144) H Wagon Road Gap (MCH 01_181); WEST lineage I Alarka (MCH 02_168) J Starr Mtn (MCH 02_156) K Backbone Rock (MCH 04_025) L Chunky Gal Mtn (MCH 02_142). Detailed specimen information provided in Suppl. material
Both nuclear and mitochondrial genetic structuring is very prominent in the California region, and our analyses show that this structure generally follows a pattern of relatedness by drainage basin (Figs
Based on bootstrap values, nuclear data strongly support the hypothesis that H. bernardino is phylogenetically nested within H. petrunkevitchi (bootstrap = 100 for all matrices across all analyses; Figs
Based on this phylogenomic pattern we see two obvious taxonomic alternatives. The first is to sink H. bernardino into a broadly distributed, highly genetically-structured H. petrunkevitchi. The second is to elevate and formally describe the distinct genetic lineage that is sister to H. bernardino. We prefer and argue for the latter approach, for reasons concisely summarized as follows: 1) H. bernardino is already described based on a diagnostic morphology (
Accepting H. bernardino as an independently evolving lineage, the current taxonomy must be updated to reflect unique lineages discovered within H. petrunkevitchi. Conservatively, we retain the northern lineages that include the type locality (male holotype of H. petrunkevitchi from Cedar Grove, Fresno County = KINGS lineage) as H. petrunkevitchi. This lineage is distributed across the Merced, San Joaquin, Kings and Kaweah River basins (Fig.
We define species as evolutionary lineages on a “unique and independent trajectory”. Following
Overall, we view our new cryptic species hypotheses as conservative, consistent with perspectives that genomic data should be interpreted conservatively when describing new species (
following
Hypochilus petrunkevitchi
Hypochilus bernardino
F from Forsee Creek (SDSU_G2893), Ms from East Fork Mountain Home Creek (SDSU_G2929–2932), see Suppl. material
Following from the original diagnosis of
Morphological measurements. PTW/PTL (maximum width of male pedipalpal tibia in retrolateral view/length of tibia in retrolateral view), CdL (male palpal conductor length in retrolateral view), AME (diameter of anterior median eye pupil), PTaL (length of male palpal tarsus in retrolateral view), CTpr (number of promarginal cheliceral teeth), CTre (number of retromarginal cheliceral teeth). Raw measurements provided in Suppl. material
PTW/PTL | CdL | AME | PTaL | CTpr | CTre | |
---|---|---|---|---|---|---|
H. bernardino | 0.253–0.267 | 0.475–0.50 | 0.1–0.125 | 0.82–1.0 | 4–5 | 2–3 |
H. petrunkevitchi YOSE lineage | 0.259–0.292 | 0.625 | 0.10–0.125 | 0.925–1.0 | 5 | 2 |
H. petrunkevitchi KING lineage | 0.278 | 0.60 | 0.10 | 0.875 | 5 | 2 |
H. petrunkevitchi KAW lineage | 0.274–0.307 | 0.575–0.675 | 0.10–0.125 | 0.925–1.15 | 4–5 | 2 |
H. xomote sp. nov. | 0.256–0.338 | 0.525–0.575 | 0.10–0.125 | 0.775–1.075 | 4–5 | 1–2 |
SRA Accession numbers: SAMN21239435–SAMN21239437.
California, San Bernardino County, San Bernardino Mountains, Camp Creek east of Forest Falls, 34.0760, -116.8876, coll. M. Hedin, 10 July 1993 (SDSU_H0025–0027, 3I). San Bernardino County, San Bernardino Mountains, Hwy 38, tributary into East Fork Mountain Home Creek, in culvert and tunnel under highway, 34.1198, -116.9768, coll. E. Ciaccio, 4 August 2018 (SDSU_G2897–2899, 3I). San Bernardino County, San Bernardino Mountains, Hwy 38, tributary into East Fork Mountain Home Creek, in culvert and tunnel under highway, 34.1198, -116.9768, coll. E. Ciaccio, 27 Sept 2018 (SDSU_G2929–2932, 4M). San Bernardino County, San Bernardino Mountains, Hwy 38, Forsee Creek, along stream and tunnel under highway, 34.1574, -116.9315, coll. E. Ciaccio, 4 August 2018 (SDSU_G2893–2896, F, 3I). See also Suppl. material
“The species most closely resembles its sister species Hypochilus petrunkevitchi in general coloration, eye dimensions, and male pedipalpal morphology. Males can be recognized by the apex of the conductor which is more loosely whorled (fig. 24) than in H. petrunkevitchi, the shorter pedipalpal tarsus, a greatly reduced distal palpal (conductor) apophysis (fig. 25), and a median palpal apophysis that is significantly smaller than H. petrunkevitchi, with no notch (fig. 7). The short palpal tibia is strongly incrassate proximally. Females … are particularly difficult to separate from H. petrunkevitchi females, the former possessing similar but smaller convoluted spermathecal ducts (fig. 11).”
Our comparisons of near-type H. bernardino to larger samples (Suppl. material
California taxa male palp (conductor) comparison. For each specimen, left panel = prolateral view, right panel = retrolateral view. H. bernardino A, B Mtn Home (SDSU_G2931) C, D Mtn Home (SDSU_G2932); H. xomote E, F Alder Creek (SDSU_G2600) G, H Tule River (SDSU_G2289); H. petrunkevitchi KINGS lineage I, J Mill Flat (SDSU_G2554); H. petrunkevitchi KAW lineage K, L Mineral King Road (SDSU_TAC000192); H. petrunkevitchi YOSE lineage M, N Yosemite (SDSU_G2568); H. kastoni O, P Ney Springs (SDSU_TAC000191). Distal conductor apophysis highlighted by arrows. Detailed specimen information provided in Suppl. material
Known only from two primary forks of a single drainage basin (headwaters of Santa Ana River, and Mill Creek, a large tributary of the Santa Ana), south side of the San Bernardino Mountains of southern California (Fig.
California taxa male palp comparison, prolateral views. H. kastoni A Ney Springs (SDSU_TAC000191); H. bernardino B Mtn Home (SDSU_G2931) C Mtn Home (SDSU_G2932); H. xomote D Tule River (SDSU_G2289) E Alder Creek (SDSU_G2600) F Belknap Springs (SDSU_G2300); H. petrunkevitchi KINGS lineage G Mill Flat (SDSU_G2554); H. petrunkevitchi KAW lineage H Mineral King Road (SDSU_TAC000192); H. petrunkevitchi YOSE lineage I Yosemite (SDSU_G2568). Median apophysis highlighted by arrows. For specimens E and I the bulb has rotated during specimen prep; these two images are retrolateral views, subsequently flipped in Photoshop. Detailed specimen information provided in Suppl. material
We view H. bernardino as a short-range endemic taxon with a precarious future, deserving of special conservation attention and monitoring efforts. Over 25 years ago,
California taxa male palp comparison, retrolateral views. H. kastoni A Ney Springs (SDSU_TAC000191); H. bernardino B Mtn Home (SDSU_G2931) C Mtn Home (SDSU_G2932); H. xomote D Tule River (SDSU_G2289) E Alder Creek (SDSU_G2600) F Belknap Creek (SDSU_G2300); H. petrunkevitchi KINGS lineage G Mill Flat (SDSU_G2554); H. petrunkevitchi KAW lineage H Mineral King Road (SDSU_TAC000192); H. petrunkevitchi YOSE lineage I Yosemite (SDSU_G2568). For specimens E and I the bulb has rotated during specimen prep; these two images are prolateral views, subsequently flipped in Photoshop. Detailed specimen information provided in Suppl. material
Hypochilus petrunkevitchi
Fs from Ladybug Trail (SDSU_G2275), Mineral King Road (SDSU_G2485), Providence Creek (SDSU_G2508), Mill Creek (SDSU_G2543), Huntington Lake Road (SDSU_G2514, SDSU_G2557), Yosemite Falls (SDSU_G2564); Ms from Atwell-Hockett Trail (SDSU_G2260), Big Fern Springs (SDSU_G2262), Ladybug Trail (SDSU_G2274), Mehrten Creek (SDSU_G2285), Mineral King Road (SDSU_TAC000192), South Fork Kaweah River (SDSU_G2279), Mill Flat (SDSU_G2254), and Yosemite Falls (SDSU_G2568, SDSU_G2569); see Suppl. material
We found that the male palpal conductor (CdL) is consistently longer in H. petrunkevitchi than in both H. bernardino and the new species below, although barely for the latter (Table
SRA Accession numbers: SAMN21239424–SAMN21239431.
Merced River drainage (YOSE): California, Mariposa County, Yosemite NP, Big Oak Flat Rd., bridge over Tamarack Creek, 37.7278, -119.7143, coll. E. Ciaccio, M. Hedin, A. Rivera, 29 Sept 2017 (SDSU_G2561–2563, 3I). Mariposa County, Yosemite NP, vic Bridalveil Falls, 37.7167, -119.6519, coll. E. Ciaccio, 3 August 2017 (SDSU_G2515–2518, 4I). Mariposa County, Yosemite NP, near Yosemite Falls, 37.7491, -119.5965, coll. E. Ciaccio, M. Hedin, A. Rivera, 29 Sept 2017 (SDSU_G2564–2566, 2I, 2F, 2M). Mariposa County, Yosemite NP, near Yosemite Falls, 37.7491, -119.5965, coll. M. Hedin, K. Crandall, 27 June 1992 (SDSU_H0015–H0016, 2I). San Joaquin River drainage (SAN): Fresno County, Sierra NF, Huntington Lake Rd., Balsam Creek turnout, 37.1884, -119.2591, coll. E. Ciaccio, 31 July 2017 (SDSU_G2510–2514, 1I, 4F). Fresno County, Sierra NF, Snowslide Creek on Huntington Lake road, 37.2029, -119.2367, coll. E. Ciaccio, 10 Sept 2017 (SDSU_G2557–2560, 1I, 3F). Kings River drainage (KING): California, Fresno County, Sierra NF, McKinley Grove Rd., Bear Creek turnout, 37.0411, -119.1202, coll. E. Ciaccio, B. Hernandez, S. Torres, J. Waters, 24 July 2017 (SDSU_G2557–2560, 4I, 1M). Fresno County, Sierra NF, McKinley Grove Big Trees Area, 37.0224, - 119.1066, coll. E. Ciaccio, 10 Sept 2017 (SDSU_G2555, G2556, 1I, 1F). Fresno County, Bretz Mill, Providence Creek, 37.0427, -119.2371, coll. E. Ciaccio, 31 July 2017 (SDSU_G2505–2509, 2M, 3F). Fresno County, Kings Canyon NP, dam at Sheep Creek on Don Cecil Trail, 36.7840, -118.6784, coll. E. Ciaccio, 9 Sept 2017 (SDSU_G2551, 1I). Fresno County, Kings Canyon NP, Road’s end permit station, Bubbs Creek/Zumwalt Meadow trail jct, 36.7918, -118.5871, coll. E. Ciaccio, 9 Sept 2017 (SDSU_G2549–2550, 1I, 1F). Fresno County, Mill Flat OHV staging area, Mill Flat Creek, 36.7452, -119.0047, coll. E. Ciaccio, 30 July 2017 (SDSU_G2502–2504, 3I). Fresno County, Sequoia NF, Mill Flat OHV Staging Area, 36.7471, -119.0046, coll. E. Ciaccio, 9 Sept 2017 (SDSU_G2552–2554, M, 2F). Fresno County, Sequoia NF, Ten Mile Rd., at bridge N of Hume Lake, 36.7838, -118.9006, coll. E. Ciaccio, 8 Sept 2017 (SDSU_G2546–2548, I, 2F). Fresno County, Sequoia NF, Ten Mile Rd., Landslide Creek turnout, 36.7625, -118.8801, coll. E. Ciaccio, 29 July 2017 (SDSU_G2497–2501, 1I, 2M, 2F). Fresno County, Sequoia NF, Hwy 245 at Mill Creek, ~1 mi S of Hwy 180 Jct, 36.7145, -118.9879, coll. E. Ciaccio, 30 July 2017 (SDSU_G2542–2545, 2I, 2F). Kaweah River drainage (KAW): Tulare County, Sequoia NP, Hwy 198, Big Fern Springs, 36.5382, -118.7751, coll. M. Hedin, 12 July 1993 (SDSU_H0020–H0022, 3I). Tulare County, Sequoia NP Hwy 198, Big Fern Springs, 36.5382, -118.7751, coll. E. Ciaccio, 17 August 2016 (SDSU_G2261–G2265, 1M, 3F, 1I). Tulare County, Sequoia NF, Forest Rte 14S11, Boulder Creek turnout, 36.7342, -118.7736, coll. E. Ciaccio, 29 July 2017 (SDSU_G2492–G2496, 1M, 4F). Tulare County, Sequoia NP, Hwy 198 near Lodgepole CG, Marble Fork Kaweah River, 36.6037, -118.7392, coll. E. Ciaccio, 29 July 2017 (SDSU_G2487–G2491, 4M, 1F). Tulare County, Sequoia NP, Mineral King Rd., Squirrel Creek pullout, 36.4428, -118.7694, coll. E. Ciaccio, 28 July 2017 (SDSU_G2482–G2486, 3M, 1F, 1I). Tulare County, Sequoia NP, Atwell-Hockett Trail, bridge on trail, 36.4584, -118.6564, coll. E. Ciaccio, 16 August 2016 (SDSU_G2256–G2260, 3M, 1F, 1I). Tulare County, Sequoia NP, bridge over Marble Fork on road to Crystal Cave, 36.5759, -118.7860, coll. E. Ciaccio, 17 August 2016 (SDSU_G2266–G2270, 4F, 1I). Tulare County, Sequoia NP, Ladybug Trail, upstream from bridge at start of trail, 36.35005, -118.76238, coll. E. Ciaccio, B. Hernandez, S. Torres, 3 Sept 2016 (SDSU_G2273–G2278, 2M, 3F, 1I). Tulare County, Sequoia NP, Middle Fork Trail, 36.5416, -118.7074, coll. E. Ciaccio, 18 August 2016 (SDSU_G2271, 1I). Tulare County, Sequoia NP, Middle Fork Trail, Mehrten Creek, 36.5457, -118.6920, coll. E. Ciaccio, B. Hernandez, S. Torres, 4 Sept 2016 (SDSU_G2284–G2288, 2M, 2F, 1I). Tulare County, Sequoia NP, Middle Fork Trail, near Mehrten Creek, 36.5456, -118.7036, coll. E. Ciaccio, 16 August 2016 (SDSU_G2272, 1I). Tulare County, Sequoia NP, Mineral King Road, turnout on the road, 36.45346, -118.6923, coll. E. Ciaccio, 18 August 2016 (SDSU_G2251–2255, 5F). Tulare County, Sequoia NP, Mineral King Road, crossing of Redwood Creek, W of Atwell Mill CG, 36.4533, -118.7036, coll. M. Hedin, 24 August 2009 (SDSU_TAC000192- TAC000193, 1F, 1M). Tulare County, Sequoia NP, South Fork Kaweah River, jnct of Cedar Creek and South Fork Kaweah River, 36.3551, -118.7335, coll. E. Ciaccio, B. Hernandez, S. Torres, 4 Sept 2016 (SDSU_G2279–G2283, 1M, 3F, 1I). Tulare County, Sequoia NP, below Atwell Mill CG, along Kaweah River, 36.4584, -118.6561, coll. M. Hedin, 23 August 2009 (SDSU_H0842- H0844, 1F, 1M, 1I). See also Suppl. material
Comparative female spermathecal morphology for California taxa. H. bernardino A Foresee Creek (SDSU_G2893); H. petrunkevitchi YOSE lineage B Yosemite (SDSU_G2564); H. xomote C Jenny Creek (SDSU_G2477) D Windy Creek (SDSU_G2465) E Belknap Creek (SDSU_G2296) F Alder Creek (SDSU_G2601); H. petrunkevitchi KAW lineage G Ladybug Trail (SDSU_G2275) H Mineral King Road (SDSU_G2485); H. petrunkevitchi KINGS lineage I Mill Creek (SDSU_G2543) J Providence Creek (SDSU_G2508); H. petrunkevitchi SAN lineage K Snowslide Creek (SDSU_G2557) L Balsam Creek (SDSU_G2415). Scale bars shown for select specimens. Detailed specimen information provided in Suppl. material
H. petrunkevitchi was previously known from a handful of locations in the west-central Sierra Nevada, and our work has greatly expanded our distributional knowledge for this species (Fig.
Of all the basins in the southern Sierra Nevada, the Kaweah and Kings populations appear to occupy the most contiguous habitat, as reflected in both nuclear phylogenies and STRUCTURE results (Figs
Holotype male (SDSU_TAC000658) from California, Kern County, upstream of Cedar Creek campground, off Hwy 155, Sequoia National Forest, 35.7508, -118.5807, elevation ~ 1520 meters, coll. M. Hedin, 4 October 2021 (MCH 21_091). Deposited at the University of California Davis Bohart Museum of Entomology. Paratype females (SDSU_TAC000659, TAC000660) and paratype male (SDSU_TAC000661) from same collecting event (MCH 21_091). Deposited at the Denver Museum of Nature and Science.
xomote, from the Native American Yowlumni tribal word for south, providing a name for the southern-most known Hypochilus populations in the California Sierra Nevada. The X of xomote is pronounced as a “breathy, hissy sort-of H” (
CdL of intermediate length (Table
SRA Accession numbers: SAMN21239432–SAMN21239434.
Male holotype – Total length 7.5. Cephalothorax 3.0 long, 2.4 wide: clypeus 0.10. Eye diameters: AME 0.125, ALE 0.225, PME 0.175, PLE 0.20. Chelicerae pale yellow to white, dusky markings at base; promarginal cheliceral teeth 5, cheliceral formula 52314, retromarginal cheliceral teeth two; one distal, one proximal, both very small. Endites and labium white to pale yellow; sternum with dusky pigmentation, small unpigmented patches circling sparse weak setae; coxae whitish; trochanters with proximal and distal pigmented patches; all legs yellow tan with broken dark annulations on femora and tibiae; prolateral proximal aspect of femur 1 with ~ 20 unpigmented weak setae; leg 1 > 20 × length of cephalothorax. Abdomen dorsally pale yellow- white with darker maculations over the entire surface, clothed with sparse hairs, with multiple transverse rows of small weak setae. Palpal tarsus (left) (0.875), palpal tibia short (1.875), thickened proximally (width 0.5), PTW/PTL = 0.267. Conductor length (0.55), conductor tip loosely whorled with very small distal apophysis in retrolateral view. Leg formula 1243; spination (only surfaces bearing spines listed): pedipalpal femur: none; tibia: many dorsal, many prolateral, few to none retrolateral; tarsus: setose with five closely appressed black spines on retrolateral surface of apical spur. Femur I-many prolateral/dorsal; legs II–IV one dorsal proximally. Trichobothrial distribution: all legs with one trichobothria distally on tibia and metatarsus.
Female paratype (SDSU_TAC000659): Total length 11.8, cephalothorax 3.8 long, 3.1 wide; clypeus 0.20. Eye diameters: AME 0.175, ALE 0.275, PME 0.225, PLE 0.20. Clypeal area, lateral aspects of head, and foveal area with dusty maculations. Pedipalp pale yellow-white, legs pale yellow-white with femora and tibiae of all legs with broken dark rings and conspicuous dark spots, first leg > 9 × length of cephalothorax. Chelicerae pale yellow, dusky on front proximal surface. Spermathecae with convoluted ducts and relatively large receptacula (e.g., Fig.
Tule River drainage: California, Tulare County, Sequoia NF, Balch Park Road, Jenny Creek, 36.2843, -118.7335, coll. E. Ciaccio, 28 July 2017 (SDSU G2477–2481, 5F). Tulare County, Sequoia NF, Hwy 190 turnout, Belknap Creek, 36.1534, -118.5977, coll. E. Ciaccio, 23 Sept 2016 (SDSU G2296–G2300, 4F, M). Tulare County, Mountain Home State Forest, Hidden Falls campground, 36.2585, -118.6631, coll. E. Ciaccio, 28 July 2017 (SDSU G2472–G2476, 2F, 3I). Tulare County, Sequoia NF, Hwy 190, McIntyre Creek turnout, 36.1509, -118.5831, coll. E. Ciaccio, 27 July 2017 (SDSU G2467–2471, 3F, 2I). Tulare County, Sequoia NF, North Fork Middle Fork Tule River, 36.2082, -118.6488, coll. E. Ciaccio, 24 Sept 2016 (SDSU G2307–G2311, 4F, M). Tulare County, Sequoia NF, Road 208, North Fork Middle Fork Tule River, 36.1879, -118.6775, coll. E. Ciaccio, 23 Sept 2016 (SDSU G2301–2306, 5F, 1I). Tulare County, Sequoia NF, Hwy 190, Middle Fork Tule River, 36.1556, -118.6688, coll. E. Ciaccio, 23 Sept 2016 (SDSU G2289–2295, 1I, 1M, 5F). Tulare County, Sequoia NF, Forest Route 21S94, Windy Creek turnout, 36.0810, -118.6055, coll. E. Ciaccio, 27 July 2017 (SDSU G2462–2466, 4F, 1I). Cedar Creek drainage: Kern County, Sequoia NF, Alder Creek campground, north side of campground along Cedar Creek, 35.7201, -118.6138, coll. E. Ciaccio & T. Bougie, 26 March 2018 (SDSU G2600–2602, 1M, 2F). Kern County, Sequoia NF, Alder Creek campground, north side of campground along Cedar Creek, 35.7201, -118.6125, coll. M Hedin & O. Hedin, 5 Sept 2020 (SDSU_TAC000657, 2M). Kern County, Hwy 155, Cedar Creek campground, Hwy 155, 35.7500, -118.5810, coll. E. Ciaccio & T. Bougie, 25 March 2018 (SDSU G2596–2599, 4I). Kern County, upstream of Cedar Creek campground, off Hwy 155, Sequoia National Forest, 35.7508, -118.5807, elevation ~ 1520 meters, coll. M. Hedin, 4 October 2021 (MCH 21_091, 1M, 4F).
Known only from the upper Tule River and upper Cedar Creek drainages, at the southern end of the California Sierra Nevada mountains (Fig.
Habitat, web, and live specimen digital images for H. xomote. From Kern County, vicinity Alder Creek campground, along Cedar Creek, 5–6 Sept 2020 (see Suppl. material
Specimens are more abundant and populations appear more secure in the densely forested and higher elevation / higher latitude Tule River drainage. Specimens are less abundant and populations appear more fragmented in the lower elevation and more southerly Cedar Creek drainage. Recent large fires have occurred in both drainages.
We dedicate this work to Dr. David Wake, a brilliant and generous herpetologist and evolutionary biologist from the Museum of Vertebrate Zoology and UC Berkeley, who passed away in early 2021. Dr. Wake’s work on California biodiversity and the speciation processes of this landscape, and his open-mindedness and appreciation for both vertebrate and invertebrates, have long served to inspire the senior author.
California specimens were collected under permit from Yosemite National Park (YOSE-2017-SCI-0039) and Sequoia/Kings Canyon National Park (SEKI-2017-SCI-0026). Several people helped to collect spiders, including Tierney Bougie, Keith Crandall, Ole Hedin, Bradley Hernandez, Andrew Rivera, Cristina Torres, and Jennifer Waters. See prior acknowledgements of
Appendix I
Data type: xslx. file
Explanation note: Specimens used in phylogenomic analysis.
Appendix II
Data type: xslx. file
Explanation note: Specimens examined and used for study of morphology.