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Pristinaspinidae, a new family of Cretaceous kiwaiform stem-lineage squat lobster (Anomura, Chirostyloidea)



The chirostyloid squat lobster Pristinaspina gelasina from the Upper Cretaceous of Alaska is most closely related to members of the genus Kiwa (Kiwaidae) as indicated by the presence of supraocular spines, a medially carinate rostrum and similar carapace groove patterns. Evidence from morphology, strati- graphic position and molecular divergence estimates of extant chirostyloids supports its position in the stem of Kiwaidae. Pristinaspina, however, also differs significantly from kiwaids and is here assigned to a new family, Pristinaspinidae. The chief distinction between the free-living pristinaspinids and vent- or seep-associated kiwaids (and an important synapomorphy of the latter) is the enlargement of the meta- branchial regions in kiwaids, which meet in the mid-line and separate the cardiac region from the intes- tinal region. The enlarged metabranchial regions of kiwaids may have improved respiration in poorly oxygenated, chemosynthetically affected waters. This appears to track a major shift in the deep-water ecology of kiwaiform squat lobsters, that is, the movement into chemosynthetic habitats.
Pristinaspinidae, a new family of Cretaceous kiwaiform
stem-lineage squat lobster (Anomura, Chirostyloidea)
S.T. Ahyong & C.N. Roterman
Ahyong, S.T. & Roterman, C.N. Pristinaspinidae, a new family of Cretaceous kiwaiform stem-lineage squat
lobster (Anomura, Chirostyloidea). In
Proceedings of the 5th-
 Scrip ta Geolo gica, 147: 125-133, 1 pl., Leiden, October 2014.
  -
           
Australia (-
KiwaPristinaspina, fossil.
The chirostyloid squat lobster Pristinaspina gelasina from the Upper Cretaceous of Alaska is most closely
related to members of the genus Kiwa
           -
graphic position and molecular divergence estimates of extant chirostyloids supports its position in the
a new family, Pristinaspinidae. The chief distinction between the free-living pristinaspinids and vent- or
branchial regions in kiwaids, which meet in the mid-line and separate the cardiac region from the intes-
tinal region. The enlarged metabranchial regions of kiwaids may have improved respiration in poorly
    
ecology of kiwaiform squat lobsters, that is, the movement into chemosynthetic habitats.
Introduction ............................................................................................................................................................ 125
Systematic palaeontology .............................................................................................................................. 
Acknowledgements ........................................................................................................................................... 129
References ................................................................................................................................................................ 129
 
et al., 2009; Schnabel
et al., 2011; Tsang et al.et al., 2013). Recent revisions of the squat
lobster system (Schnabel & Ahyong, 2010; Ahyong et al.-
           
group, but the aforementioned phylogenetic studies have shown that the galatheoids
and chirostyloids are not sister groups, but appear to have convergently evolved a sim-
      -
 Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster.
 et al.
record is presently poor, being known only from two species, Pristinaspina gelasina
Eouroptychus montema-
grensisEouroptychus corresponds to
the current concept of Chirostylidae, but the position of Pristinaspina is less clear. Pristi-
of the Chirostylidae, however, Pristinaspina cannot be readily accommodated there, with
its supraorbital spines, broad, medially carinate rostrum and well-marked branchiocar-
spines and a median carina on the rostrum. Unlike eumunidids, Pristinaspina has neither
a spiniform rostrum nor a transversely striated carapace. The broad, carinate rostrum,
       -
pace of Pristinaspina, Pristi-
naspina gelasina         
Systematic palaeontology
Superfamily Chirostyloidea Ortmann, 1892
Family Pristinaspinidae nov.
Type genusPristinaspina
Stratigraphic range
regions; surface regularly dimpled, without transverse striae or dorsal spines, regions
  -
praorbital spines slender, well developed. Carapace margins spinose, with 3 hepatic
marginal spines posterior to supraocular spines, 2 spines on anterior epibranchial mar-
gins, 1 metabranchial spine at base of branchiocardiac groove. Cervical groove well
     
   -
branchial regions. Anterior part of branchiocardiac groove subparallel to cervical
groove, between them enclosing triangular mesobranchial and epibranchial regions;
epibranchial region slightly larger and more swollen than mesobranchial region. Car-
diac and intestinal regions fused, hourglass shaped, anteriorly as wide as metagastric
region, separating metabranchial regions.
Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster. 
gionalisation of pristinaspinids and kiwaids is similar, albeit somewhat less pronounced
regions in kiwaids, which are more expanded and meet in the midline, separating the
cardiac region from the intestinal region. Conversely, the metabranchial regions in pris-
tinaspinids, although wide, are clearly separated by the fused cardiac and intestinal
      
than strongly divergent cervical and branchiocardiac grooves; mesobranchial regions
slightly smaller, rather than markedly smaller than the epibranchial regions; and prom-
inently spinose rather than unarmed lateral carapace margins. For comparison with
is given below.
Shared morphological features between pristinaspinids and kiwaids, along with
stratigraphic position of P. gelasina 
     
would also be possible (Ahyong et al.-
gene phylogenetic analysis, however, suggest that the common ancestor of Chirosty-
   
Cretaceous (Roterman et al., 2013). Thus, combined evidence from morphology, stratig-
waidae, supporting a kiwaiform clade. The former presence of Pristinaspina in deep
   Kiwa, suggests that kiwaids may have evolved in deep
            
(Roterman et al., 2013).
Pristinaspina gelasina      -
trichtian) non-chemosynthetic, siliciclastic deposits in Alaska. These deposits from the
deep continental slope have associated thalassinidean remains but no corals, indicating
mann, 2000). Thus, P. gelasina was probably free living, neither associated with live
           et al.,
2010), nor chemosynthetic habitats, like modern kiwaids (Roterman et al., 2013). The
relatively swollen branchial regions of Pristinaspinidae compared to most other squat
  Cervimunida and Pleuroncodes in the
    
more tolerant of less oxic conditions prior to the move by kiwaids to chemosynthetic
 et al., 2010).
All known species of Kiwa
‘farm’ sulfur-reducing bacteria on which the animal feeds (Thurber et al., 2011). The
phylogeny of the few known species of Kiwa is consistent with a possible transition
      
     
 Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster.
        et al. 
         vice versa, however, remains to be
tested through discovery of additional species of Kiwa, although the distinction be-
     
        
et al., 2011). Regardless of the precise mode of transition, the late Paleogene/early
   et al.,   et al., 2010), where methane seeps,
hydrothermal vents and non-chemosynthetic continental slope habitats are likely to
have been in very close proximity.
Either way, the ecological transition into arguably more extreme habitats might
account for the further expansion of the branchial regions in kiwaids as a means of
movement into chemosynthetic habitats. It is worth mentioning that the late Paleo-
 et al., 2013) coincides with a dra-
    -
cene/Oligocene transition (Pälike et al., 2012), possibly indicating that prior to this
tilated deep-sea may have been responsible for the widespread extinction of vent and
seep-associated megafauna, with present-day diversity the consequence of subsequent
    
event (Roterman et al., 2013), possibly later than other vent and seep endemic faunas
of kiwaids to ambient oxygen levels than many other chemosynthetic taxa, as evi-
nidae. Indeed, the indication, based on molecular divergences, that the other vent and
diated in these habitats more recently than many other taxa (Shank et al.-
hoek, 2013) raises the possibility that decapods as a whole are possibly evolutionarily
constrained by the internal placement of their branchiae under the carapace, thus lim-
 -
ated conditions.
At present, the fossil record of clades neighbouring the chirostyloids is sparse. Lo-
misoids, endemic to southeastern Australia, have no known fossil record. Along with
Pristinaspina           
many other decapods originated at high latitudes during the Cretaceous (Feldmann &
   
north and south, respectively. That both pristinaspinids and aegloids have Cretaceous
Tethyan origin for the chirostyloid-aegloid-lomisoid clade (Ahyong et al., 2011).
Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster. 129
Kiwaidae Macpherson, Jones & Segonzac, 2005
Type genus Kiwa        
Stratigraphic range
      
regions; transverse or slightly inclined anteriorly either side of midline, always oblique
to cervical groove. Subtriangular mesobranchial and polygonal epibranchial regions.
Epibranchial region markedly larger than mesobranchial region. Cardiac region subtri-
angular, as long as or longer than wide, anterior margin convex; intestinal region trian-
gular, markedly wider than long. Cardiac and intestinal regions separated by medially
RemarksKiwa, with two described species,
K. puravidaK. hirsuta
et al., 2012) and pos-
et al., 2013).
 
           
Scotia Ridge and Southwest Indian Ridge kiwaids was funded by NERC Consortium
   
In    Decapod crustacean phylogenetics (Crustacean
Issues, 18): 399-414.
    
lobsters. InThe biology of squat lobsters (Crustacean
Issues, 19
 -
Zootaxa, 1905: 1-220.
130 Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster.
          
BMC Evolutionary Biology, 13
      Eouroptychus montemagrensis      
trionale). Lavori – Società Veneziana di Scienze Naturali, 37: 19-24.
cea. Journal of Paleontology, 80
tebrates. Environmental Microbiology Reports, 2
           
Hydrobiologia, 535
sea mussels. Marine Biology, 148
Eumunida picta Lophelia pertusa 
Crustaceana, 81
Gastroptychus formosus and cold-water corals in the North Atlantic. Journal of the Marine Biological
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Marine Ecology, 31: 94-110.
 Zoosystema, 27:
      -
Geosphere, 2: 11.
           -
straints from paleogeographic reconstructions. International Journal of Earth Sciences, 90
           
Anomoures. 
und Paguridea. Zoologische Jahrbücher, Abteilung für Systematik, Ökologie und Geographie der Tiere, 6:
 
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    
            
     
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The entomologists’ useful compendium; or an introduction to the knowledge of British
Insects, comprising the best means of obtaining and preserving them, and a description of the apparatus
generally used; together with the genera of Linné, and modern methods of arranging the Classes Crustacea,
Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster. 131
Also an explanation of the terms used in entomology; a calendar of the times of appearance and usual situa-
         
microscope. 
          
western North America controlled by evolving width of farallon slab. Science, 329
      
Anomura). Zootaxa, 2687
     
        
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132 Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster.
Plate 1
Fig. 1. Pristinaspina gelasina  
Fig. 2. Kiwa puravida
Fig. 3. Kiwa hirsuta, courtesy of
Fig. 4. Kiwa sp., East Scotia Ridge.
Fig. 5. Kiwa sp., southwest Indian Ridge.
Scale bars equal 2 mm (Fig. 1) and 10 mm (Figs. 2-5).
Ahyong & Roterman. Pristinaspinidae, a stem-lineage squat lobster. 133
... GM on the Galapagos Microplate, along with the location of K. araonae in the Pacific sector of the Southern Ocean on the Australian-Antarctic Ridge (AAR) tallies with previous interpretations [26,70], based on the Pacific locations of K. puravida and K. hirsuta, that Kiwaidae likely originated in the Pacific. This is also consistent with the assignment of the Alaskan fossil Pristinaspina gelasina on the stem of Kiwaidae [66]. Roterman et al. [26] further speculated, based on the location of P. gelasina and the basal split between the Costa Rican K. puravida and other kiwaids, that Kiwaidae may have originated in the Northern Hemisphere. ...
... Decapods house gills enclosed in branchial chambers which are ventilated by the beating of the paddle-like scaphognathite under the dorsal carapace. Those that are chemosynthetically-associated have greater scaphognathite and gill surface area for gas exchange compared to their non-chemosynthetic relatives [86] and the branchial chambers of kiwaids are substantially larger than those of the apparently non-chemosynthetic stem lineage P. gelasina [66]. However, the housing of gills internally and the energetic costs of beating larger scaphognathites may place tighter constraints on the efficiency of gas exchange in hypoxic conditions, compared to species that can have external gasexchange organs such as annelids [86]. ...
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The recent discovery of two new species of kiwaid squat lobsters on hydrothermal vents in the Pacific Ocean and in the Pacific sector of the Southern Ocean has prompted a re-analysis of Kiwaid biogeographical history. Using a larger alignment with more fossil calibrated nodes than previously, we consider the precise relationship between Kiwaidae, Chirostylidae and Eumunididae within Chirostyloidea (Decapoda: Anomura) to be still unresolved at present. Additionally, the placement of both new species within a new “Bristly” clade along with the seep-associated Kiwa puravida is most parsimoniously interpreted as supporting a vent origin for the family, rather than a seep-to-vent progression. Fossil-calibrated divergence analysis indicates an origin for the clade around the Eocene-Oligocene boundary in the eastern Pacific ~33–38 Ma, coincident with a lowering of bottom temperatures and increased ventilation in the Pacific deep sea. Likewise, the mid-Miocene (~10–16 Ma) rapid radiation of the new Bristly clade also coincides with a similar cooling event in the tropical East Pacific. The distribution, diversity, tree topology and divergence timing of Kiwaidae in the East Pacific is most consistent with a pattern of extinctions, recolonisations and radiations along fast-spreading ridges in this region and may have been punctuated by large-scale fluctuations in deep-water ventilation and temperature during the Cenozoic; further affecting the viability of Kiwaidae populations along portions of mid-ocean ridge.
... Other diverse reef assemblages originate from the mid-Cretaceous of Spain (Klompmaker et al. 2012a) and the Eocene-Oligocene of Italy (De Angeli and Garassino 2002). Conversely, only two fossil species of Chirostyloidea have been confirmed: the Late Cretaceous Pristinaspina gelasina (Schweitzer and Feldmann 2000;Ahyong and Roterman 2014) from siliciclastic rocks of Alaska and the Eocene Eouroptychus montemagrensis from a coral limestone of Italy (De Angeli and Ceccon 2012). If the Tithonian-Berriasian seep decapod is indeed a galatheoid appendage, this diverse group inhabited cold seeps early on in their evolutionary history. ...
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Numerous crustaceans such as ostracods, decapod crustaceans, and some barnacles inhabit modern cold seep ecosystems, but little is known about their fossil record in these chemosymbiotic-based ecosystems. Consequently, their importance in structuring faunas at these biodiversity hotspots on the sea floor is poorly known, including to what extent seeps acted as refuges from extinction, the timing of occupancy of cold seeps, the degree of endemism, depth preferences, and the longevity of crustacean lineages. We provide the first synthesis of crustaceans in ancient seeps and show that they have been found in each continent due to a rapid increase in research since the 1990s. Ostracods and barnacles are known from body fossils alone. Conversely, decapods are represented by two types of fossils: body fossils primarily attributed to true crabs and ghost shrimps and their traces such as coprolites, repair scars, and burrows. The last ~150 million years saw a remarkable rise in the number of localities and occurrences of seep crustaceans, mostly caused by the diversification of decapods in a variety of environments including seeps. Although considerable progress was made in 30 years, the relatively unexplored fossil record of seep crustaceans provides ample opportunities for further taxonomic, macroevolutionary, and paleoecological research.KeywordsArthropodaAxiideaBarnacleBrachyuraBurrowCirripediaCoproliteCrustaceaDecapodaMethane seepOstracodaRepair scarTrace fossil
... Contributions to the present issue include an overview of Pál's scientific output (Hyžný et al., 2014a), as well as a range of papers on Late Jurassic to Quaternary anomurans and brachyurans, as follows: (Ahyong & Roterman, 2014); • latest Cretaceous icriocarcinids from North America (Nyborg et al., 2014) and coeval 'odds and ends' amongst decapod crustaceans from the type area of the Maastrichtian Stage (Jagt et al., 2014b); ...
... The squat lobsters are one of the most diverse groups of deep sea animals, and are prevalent in both hydrothermal vent and cold seep environment. To our knowledge, forty-one species have been reported as colonists or vagrants in these chemosynthetic ecosystems, twenty of which were newly recorded after Martin & Haney's review (Martin & Haney 2005;Cubelio et al. 2007aCubelio et al. -c, 2008Macpherson 2007;Jones & Macpherson 2007;Thurber et al. 2011;Liu et al. 2013;Ahyong & Roterman 2014;Thatje et al. 2015). Among them, six species are from the western Pacific: Munidopsis gracilis Cubelio, Tsuchida & Watanabe, 2008, M. kermadec Cubelio, Tsuchida & Watanabe, 2007, M. longispinosa Cubelio, Tsuchida & Watanabe, 2007, M. myojinensis Cubelio, Tsuchida, Hendrickx, Kado & Watanabe, 2007, M. naginata Cubelio, Tsuchida & Watanabe, 2007and M. ryukyuensis Cubelio, Tsuchida & Watanabe, 2007 naginata is from both hydrothermal vents in the Okinawa Trough and cold seeps off Sagami Bay; Cubelio et al. 2007aCubelio et al. -c, 2008; five species are from the eastern Pacific: Kiwa hirsuta Macpherson, Jones & Segonzac, 2005, K. puravida Thurber, Jones & Schnabel, 2011, M. bracteosa Jones & Macpherson, 2007, M. recta Baba, 2005 and M. scotti Jones & Macpherson, 2007; seven species are from the Atlantic Ocean: M. acutispina Benedict, 1902, M. exuta Macpherson & Segonzac 2005, M. geyeri Pequegnat & Pequegnat, 1970, M. hirtella Macpherson & Segonzac 2005 livida (Perrier, 1886), M. marionis (A. ...
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Six species of squat lobsters from a cold seep field in the northeastern South China Sea are studied. Two new species, Uroptychus jiaolongae n. sp. and U. spinulosus n. sp., are described, and their distinctions from the related species are detailed. Two species, Munidopsis tuberosa Osawa, Lin &Chan, 2008 and M. verrilli Benedict, 1902, are herein reported for the first time from a cold seep/hydrothermal vent environment. The number of squat lobsters species associated with those chemosynthetic environments now stands at forty-one.
... Henderson (1888) reports Munidopsis antonii (Filhol, 1884) from southwest of Australia at 50°S, and Schnabel (2009) reports Gastroptychus novaezelandiae Baba, 1974, from southern New Zealand at 53°S. Most recently, Ahyong (2014) reported Munidopsis pyrochela Ahyong, 2014 from the Macquarie Ridge (50°S) and Marsh et al. (2015) report an undescribed species of yeti crab (Kiwa sp.) from hydrothermal vent fields on the East Scotia Ridge (see also Roterman et al., 2013; Ahyong & Roterman, 2014:fig. 4). ...
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Macquarie Ridge is one of the southernmost seamount ridges, spanning 1600 kilometres from the southern tip of New Zealand to the Australia-Pacific-Antarctic triple junction halfway to Antarctica. Squat lobsters, superfamilies Chirostyloidea and Galatheoidea, are highly diverse at low and mid-latitudes, declining rapidly towards the poles; only 15 of the more than 1000 species have been recorded south of 50 degrees S. Prior to the present study, one species of squat lobster (Munidopsis pyrochela, Munidopsidae) was known from the Macquarie Ridge, but recent research voyages in 2003 and 2008 collected a further five species from both superfamilies and three families. Uroptychus tracey (Chirostylidae) is new to science. Uroptychus insignis (Henderson, 1885) is reported for the first time outside of the western Indian Ocean and re-described based on type material. Subtle differences between the western Indian Ocean and Macquarie Ridge specimens of U. insignis suggest that the latter specimens might represent a separate species. Munida chathamensis Baba, 1974 (Munididae) is re-described and reported for the first time outside of its Chatham Rise type locality. New morphological variation is reported for Munida isos. Munidopsis tasmaniae is reported not only for the first time from the Macquarie Ridge, but also for the first time from New Zealand waters.
A new species of deep-sea yeti crab, Kiwa araonae, is described from a hydrothermal vent field, Mujin (“Misty Harbor”), at a depth of about 2000 m on the Australian-Antarctic Ridge (AAR), Southern Ocean. The Mujin vent field (62°11.79′S), in a large, unexplored gap in the Circum-Antarctic Ridge system, is the most southern record for a yeti crab to date. Kiwa araonae n. sp. is the fourth described species in the family Kiwaidae Macpherson, Jones and Segonzac, 2005, and the second known from the Southern Ocean. This new species differs morphologically from its three congeners by the having a nearly flat branchial region, relatively short rostrum, third sternite with parallel lateral margins, slender chela, straight fingers of the chela, and propodi of pereiopods 2-4 with three corneous spines on the flexor margins. The Bayesian phylogenetic tree and the genetic distance based on the mitochondrial 16S rRNA gene (408 bp) clearly indicate the distinctiveness of this species. The discovery of Kiwa araonae in the AAR suggests a possible biogeographic connection of the Southern Ocean vent faunas. The presence of a new hydrothermal vent field with endemic species in the AAR provides additional information on the global biogeography of deep-sea vent faunas.
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The phylogeny of the superfamily Chirostyloidea (Decapoda: Anomura) has been poorly understood owing to limited taxon sampling and discordance between different genes. We present a nine-gene dataset across 15 chirostyloids, including all known yeti crabs (Kiwaidae), to improve the resolution of phylogenetic affinities within and between the different families, and to date key divergences using fossil calibrations. This study supports the monophyly of Chirostyloidea and, within this, a basal split between Eumunididae and a Kiwaidae-Chirostylidae clade. All three families originated in the Mid-Cretaceous, but extant kiwaids and most chirostylids radiated from the Eocene onwards. Within Kiwaidae, the basal split between the seep-endemic Kiwa puravida and a vent clade comprising Kiwa hirsuta and Kiwa spp. found on the East Scotia and Southwest Indian ridges is compatible with a hypothesized seep-to-vent evolutionary trajectory. A divergence date estimate of 13.4-25.9 Ma between the Pacific and non-Pacific lineages is consistent with Kiwaidae spreading into the Atlantic sector of the Southern Ocean via the newly opened Drake Passage. The recent radiation of Kiwaidae adds to the list of chemosynthetic fauna that appear to have diversified after the Palaeocene/Eocene Thermal Maximum, a period of possibly widespread anoxia/dysoxia in deep-sea basins.
InThe biology of squat lobsters (Crustacean Issues, 19Zootaxa
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