Eastern Pacific Region Research Articles

The control of the tropical North Atlantic on Holocene millennial climate oscillations

Abstract Changes in ocean dynamics in the northern North Atlantic affect the thermohaline circulation that controls global climate. During glacial and deglaciation periods these dynamics are enhanced due to large variations in the surface ocean density caused by changes in glacier volumes. During full interglacial conditions, the dominant role of the northern North Atlantic on global climate is limited due to the reduced discharge of freshwater to the ocean, causing other regional dynamics to gain importance. Here we present a speleothem δ18O record from the Iberian Peninsula that supports that the northern North Atlantic and tropical North Atlantic were both source regions of millennial climate oscillations during the Holocene. The speleothem δ18O signal records millennial time-scale changes in the hydrological cycle as a result of persistent anomalies of the Gulf Stream–North Atlantic Current dynamics. In addition, the speleothem δ18O record shows synchronous variability with records from the eastern Pacific region though the entire Holocene, whereas records from western Pacific region have limited or no correlation beyond periods of major instability of the northern North Atlantic. The discontinuous climate connection among the studied records is the result of different mechanisms affecting the climate system that originated in distant regions. We suggest that two regions, the tropical North Atlantic and northern North Atlantic, alternate their dominance as source regions causing millennial climate anomalies in large planetary regions. The duration of these persistent climate changes and the extension of the regions affected depend on the region triggering the anomaly because different mechanisms affecting the climate system are involved.

Eotaria citrica, sp. nov., a new stem otariid from the "Topanga" formation of Southern California.

A new taxon of stem otariid, Eotaria citrica sp. nov., is described from the upper Burdigalian to lower Langhian “Topanga” formation of Orange County, California. The new species is described from mandibular and dental remains that show a unique combination of plesiomorphic and derived characters. Specifically, it is characterized by having trenchant and prominent paraconid cusps in p3–m1, lingual cingula of p2–4 with faint crenulations, premolars and molars with vestigial metaconid, bilobed root of m2 and a genial tuberosity located under p3. Furthermore, additional material of the contemporaneous Eotaria crypta is described, providing new information on the morphology of this taxon. Both species of Eotaria represent the earliest stem otariids, reinforcing the hypothesis that the group originated in the north Eastern Pacific Region. At present, the “Topanga” Fm. pinniped fauna includes Eotaria citrica, Eotaria crypta, the desmatophocid Allodesmus sp., the odobenids Neotherium sp., Pelagiarctos sp. and includes the oldest records of crown pinnipeds in California. Overall this pinniped fauna is similar to the nearly contemporaneous Sharktooth Hill bonebed. However, unambiguous records of Eotaria are still missing from Sharktooth Hill. This absence may be due to taphonomic or paleoenvironmental factors. The new “Topanga” record presented here was integrated into an overview of the late Oligocene through early Pleistocene pinniped faunas of Southern California. The results show an overall increase in body size over time until the Pleistocene. Furthermore, desmatophocids were the largest pinnipeds during the middle Miocene, but were extinct by the beginning of the late Miocene. Odobenids diversified and became the dominant pinnipeds in late Miocene through Pleistocene assemblages, usually approaching or exceeding 3 m in body length, while otariids remained as the smallest taxa. This pattern contrasts with modern assemblages, in which the phocid Mirounga angustirostris is the largest pinniped taxon in the region, odobenids are extinct and medium and small size ranges are occupied by otariids or other phocids.

Revision of the family Chasmocarcinidae Serène, 1964 (Crustacea, Brachyura, Goneplacoidea).

The family Chasmocarcinidae Serène, 1964, is revised based on the examination of the type material of many of its species as well as unidentified and previously identified material from around the world. The revised family now consists of three subfamilies comprising 16 genera (including eight described as new) and 51 species (including 19 described as new). The subfamily Chasmocarciinae Serène, 1964, consists of Amboplax n. gen. with one species; Angustopelta n. gen. with four species, two of which are new; Camatopsis Alcock & Anderson, 1899, with six species, five of which are new; Chasmocarcinops Alcock, 1900, with one species; Chasmocarcinus Rathbun, 1898, with 11 species, one of which is new; Chinommatia n. gen. with five species, two of which are new; Deltopelta n. gen. with one species; Hephthopelta Alcock, 1899, with two species, one of which is new; Microtopsis Komai, Ng & Yamada, 2012, with two species, one of which is new; Notopelta n. gen. with one species; Statommatia n. gen. with five species, two of which are new; and Tenagopelta n. gen. with three species, two of which are new. The subfamily Megaesthesiinae Števčić, 2005, consists of Alainthesius n. gen. with two species, both of which are new; Megaesthesius Rathbun, 1909, with four species, one of which is new. The subfamily Trogloplacinae Guinot, 1986, consists of Australocarcinus Davie, 1988, with three species, and Trogloplax Guinot, 1986, with one species. A neotype is selected for Chasmocarcinus cylindricus Rathbun, 1901. Three nominal species were found to be junior subjective synonyms of other species: Chasmocarcinus panamensis Serène, 1964, of C. longipes Garth, 1940; Chasmocarcinus rathbuni Bouvier, 1917, of C. typicus Rathbun, 1898; and Hephthopelta superba Boone, 1927, of Deltopelta obliqua (Rathbun, 1898). Thirteen chasmocarcinid genera are exclusively found in the Indo-West Pacific region, one (Chasmocarcinus) in both the Western Atlantic and Tropical Eastern Pacific regions, and two (Deltopelta n. gen. and Amboplax n. gen.) exclusively in the Western Atlantic. Chasmocarcinids are remarkable for occurring from depths exceeding 1000 m to shallow water and completely freshwater habitats: chasmocarcinines and megaesthesiines are found from shallow to deep water marine ecosystems, whereas trogloplacines live in freshwater streams, including cave systems.

Unusual reef fish biomass and functional richness at Malpelo, a remote island in the Tropical Eastern Pacific

Fish assemblages can vary across temporal and spatial scales due to changes in habitat structure and the influence of local factors such as wave exposure, depth and anthropogenic influence. This study presents a description of species richness, functional richness, density and biomass of fish assemblages of Malpelo Island, a Marine Protected Area located in the Tropical Eastern Pacific (TEP) region and considered a World Heritage site. Underwater visual censuses (n = 103) from two years and a local checklist were used to characterize the reef fish assemblage of Malpelo Island. Our results show a numerical dominance, during both sampling years, by the planktivore species Chromis atrilobata and Apogon atradorsatus, which are regional TEP endemic species. Among the most striking results found were the high biomass values (706.2 g/m2 ± 73.2 in 2010 and 879 g/m2 ± 116.2 in 2015) of large-bodied TEP endemic piscivorous species and the high functional diversity represented mainly by vulnerable species. The dominance in density and biomass of regional endemic species exemplifies the high endemism level within the TEP. High levels of fish biomass and functional richness suggest that Malpelo is one of the most pristine and vulnerable sites within the TEP region. Thus, Malpelo island represents a baseline for untouched assemblages in this marine province, as well as a priority area for conservation at the national and international level.

Using Empirical Mode Decomposition to Filter Out Non-turbulent Contributions to Air–Sea Fluxes

A methodology based on Empirical mode decomposition (EMD) was used to filter out non-turbulent motions from measurements of atmospheric turbulence over the sea, aimed at reducing their contribution to eddy-covariance (EC) estimates of turbulent fluxes. The proposed methodology has two main objectives: (1) to provide more robust estimates of the fluxes of momentum, heat and CO\(_2\); and (2) to reduce the number of flux intervals rejected due to non-stationarity criteria when using traditional EC data processing techniques. The method was applied to measurements from a 28-day cruise (HALOCAST 2010) in the Eastern Pacific region. Empirical mode decomposition was applied to 4-h long time series data and used to determine the cospectral gap time scale, \(T_\mathrm{{gap}}\). Intrinsic modes of oscillation with characteristic periods longer than the gap scale due to non-turbulent motions were assumed and filtered out. Turbulent fluxes were then calculated for sub-intervals of length \(T_\mathrm{{gap}}\) from the filtered 4-h time series. In the HALOCAST data, the gap scale was successfully identified in 89% of the 4-h periods and had a mean of 37 s. The EMD approach resulted in the rejection of 11% of the flux intervals, which was much less than the 68% rejected when using standard filtering methods based on data non-stationarity. For momentum and sensible heat fluxes, the averaged difference in flux magnitude between the traditional and EMD approaches was small (3 and 1%, respectively). For the CO\(_2\) flux, the magnitude of EMD flux estimates was on average 16% less than fluxes estimated from linear detrended 10-min time series. These results provide evidence that the EMD method can be used to reduce the effects of non-turbulent correlations from flux estimates.

Maritime transportation of illegal drugs from South America

BackgroundThe US invests considerable effort in searching and interdicting drug-trafficking vessels in the Caribbean and Eastern Pacific regions. While some vessels are indeed interdicted, resulting in confiscation of substantial quantities of drugs, many such vessels manage to avoid detection and arrive safely at their destinations in Central America and Mexico with their drug load intact. The agency in charge of interdicting this traffic, Joint Interagency Task Force South—JIATF-S, sends out both aerial and surface assets for search and interdiction missions. MethodsAn important parameter for planning search and interdiction missions is an estimate of the expected steady-state number of the various types of drug trafficking vessels present in the search regions at any given time. In this paper we use various publicly available sources to estimate these numbers. ResultsWe estimate that the number of drug shipments initiated per month ranges between four and six dozen, and at any given time there are between two and four vessels, of all types, on the high seas. These estimates remain quite robust over a relatively large range of assumptions and estimates regarding the size and distribution of the drug flow, mix of vessel types, and physical characteristics of those vessels. ConclusionOur analysis provides insight for how to allocate assets to search, detect, and interdict drug trafficking vessels. The results can also be useful to vet informants to check if their information is consistent with our flow estimates. To the best of our knowledge this is the first time such flow estimates appear in the open literature.

Sound velocities of olivine at high pressures and temperatures and the composition of Earth's upper mantle

AbstractWe present the elastic properties of San Carlos olivine up to P = 12.8(8) GPa and T = 1300(200) K using Brillouin spectroscopy with CO2 laser heating. A comparison of our results with the global seismic model AK135 yields average olivine content near 410 km depth of about 37% and 43% in a dry and wet (1.9 wt % H2O) upper mantle, respectively. These olivine contents are far less than in the pyrolite model. However, comparisons of our results with regional seismic models lead to very different conclusions. High olivine contents of up to 87% are implied by seismic models of the western U.S. and eastern Pacific regions. In contrast, we infer less than 35% olivine under the central Pacific. Strong variations of olivine content and upper mantle lithologies near the 410 km discontinuity are suggested by regional seismic models.

The Time Scales of Variability of Marine Low Clouds

AbstractMultidecade global regressions of inversion strength, vertical velocity, and sea surface temperature (SST) on low cloud amount, from subdaily to multiyear time scales, refute the dominance of seasonal inversion strength on marine low cloud variability. Multiday low cloud variance averaged over the eastern Pacific and Atlantic stratocumulus regions [5 × 10−2 (cloud amount)2] is twice the subdaily variance and 5 times larger than the multimonth variance. The broad multiday band contains most (60%) of the variance, despite strong seasonal (annual) and diurnal spectral peaks. Multiday low cloud amount over the eastern tropical and midlatitude oceans is positively correlated to inversion strength, with a slope of 2%–5% K−1. Anecdotes show multiday low cloud and inversion strength anomalies propagate equatorward from midlatitudes. Previously shown correlations of low clouds to strong inversions and cool SST on monthly and longer time scales in the stratocumulus regions imply positive cloud-radiative feedbacks, with e-folding time scales of 300 days for SST and 14 days for atmospheric boundary layer temperature. On multimonth time scales, removing the effect of SST on low clouds reduces the low cloud amount explained by inversion strength by a factor of 3, but SST has a small effect at other time scales. Contrary to their positive correlation in the stratocumulus cloud decks, low clouds are anticorrelated to inversion strength over most of the tropics on daily and subdaily time scales.

Marine boundary layer structure as observed by A-train satellites

Abstract. The marine boundary layer (MBL) structure is important to the marine low cloud processes, and the exchange of heat, momentum, and moisture between oceans and the low atmosphere. This study examines the MBL structure over the eastern Pacific region and further explores the controlling factors of MBL structure over the global oceans with a new 4-year satellite-based data set. The MBL top (boundary layer height, BLH) and the mixing layer height (MLH) were identified using the MBL aerosol lidar backscattering from the CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations). Results showed that the MBL is generally decoupled with MLH ∕ BLH ratio ranging from ∼ 0.5 to ∼ 0.8 over the eastern Pacific Ocean region. The MBL decoupling magnitude is mainly controlled by estimated inversion strength (EIS), which in turn controls the cloud top entrainment process. The systematic differences between drizzling and non-drizzling stratocumulus tops also show dependence on EIS. This may be related to the meso-scale circulations or gravity wave in the MBL. Further analysis indicates that the MBL shows a similar decoupled structure for clear-sky and cumulus-cloud-topped conditions, but is better mixed under stratiform cloud breakup and overcast conditions.

ENSO-driven energy budget perturbations in observations and CMIP models

Various observation-based datasets are employed to robustly quantify changes in ocean heat content (OHC), anomalous ocean–atmosphere energy exchanges and atmospheric energy transports during El Nino-Southern Oscillation (ENSO). These results are used as a benchmark to evaluate the energy pathways during ENSO as simulated by coupled climate model runs from the CMIP3 and CMIP5 archives. The models are able to qualitatively reproduce observed patterns of ENSO-related energy budget variability to some degree, but key aspects are seriously biased. Area-averaged tropical Pacific OHC variability associated with ENSO is greatly underestimated by all models because of strongly biased responses of net radiation at top-of-the-atmosphere to ENSO. The latter are related to biases of mean convective activity in the models and project on surface energy fluxes in the eastern Pacific Intertropical Convergence Zone region. Moreover, models underestimate horizontal and vertical OHC redistribution in association with the generally too weak Bjerknes feedback, leading to a modeled ENSO affecting a too shallow layer of the Pacific. Vertical links between SST and OHC variability are too weak even in models driven with observed winds, indicating shortcomings of the ocean models. Furthermore, modeled teleconnections as measured by tropical Atlantic OHC variability are too weak and the tropical zonal mean ENSO signal is strongly underestimated or even completely missing in most of the considered models. Results suggest that attempts to infer insight about climate sensitivity from ENSO-related variability are likely to be hampered by biases in ENSO in CMIP simulations that do not bear a clear link to future changes.

New records of snipe eels (Anguilliformes: Nemichthyidae) from the Pacific coast of lower Central America

New records of occurrence of two snipe eels (Avocettina bowersii and Nemichthys scolopaceus), poorly known for the Pacific coast of Costa Rica and Panama are herein reported. Specimens, 45 in total (28 and 17, respectively), were collected between 1972 and 1973 at depths between 295 and 1000 m. Descriptions based on specimens as well as comparative morphometric and distributional information by species are herein presented and discussed. A key to the identification of the eastern Pacific species of the family also is presented. These findings increase the knowledge on the Central American marine ichthyofauna and provide evidence of a broader distributional pattern for these species in the eastern Pacific region.

Influence of ENSO on Regional Indian Summer Monsoon Precipitation—Local Atmospheric Influences or Remote Influence from Pacific

Using CMIP5 model outputs in different El Niño-Southern Oscillation (ENSO) phases, this work investigates the indicator that could be used as an Index to characterise regional Indian Summer Monsoon (ISM) precipitation. Dividing the Indian subcontinent into five arbitrarily chosen regions, viz. Central North East (CNE) (18°N–31°N, 86°E–75°E), Hilly (H) (28°N–38°N, 85°E–70°E), North West (NW) (21°N–31°N, 79°E–67°E), North East (NE) (21°N–31°N, 86°E–97°E) and Southern India (S) (18°N–7°N, 73°E–85°E), local wind field and remote influences from the tropical Pacific are considered to improve understanding of regional monsoon rainfall. Results are also compared with observations/reanalysis data to pinpoint areas of shortcomings and agreements. Model results suggest that regional wind velocity, viz. meridional wind component (V) at 850 mb level (V850) and zonal component at 200 mb (U200) and 850 mb (U850) can yield better estimation of local precipitation in regions CNE, H and NW, agreeing well with earlier proposed monsoon Indices. Such observations are independent of different subcategories of ENSO phases and models show good correspondence with observations. Analyses with V at 200 mb (V200) indicate circulation of the upper branch of Hadley cells in regions CNE and S, though suggest the best agreement among models in comparison with other fields, but there are some deviations from observations, indicating a missing mechanism in the models. Using models, this study identified the best parameter in different regions that could be used for the regional monsoon Index, irrespective of various ENSO subcategories; for CNE it is the U200, for H it is U200 and U850, and for NW it is U850. The current analysis, however, fails to indicate anything clearly about the NE region. When focusing on the remote influence from the eastern Pacific region, it is found that atmospheric contribution to regional ISM precipitation fails to indicate consistent roles among models, but sea surface temperature suggests strong connection. However, remote influence from the Central Pacific is captured uniformly in models via zonal components of wind in the H and NW regions.

Tidal and Diel Patterns in Abundance and Feeding of a Marine-Estuarine-Dependent Fish from Macrotidal Mangrove Creeks in the Tropical Eastern Pacific (Colombia)

Mangrove ecosystems are nursery habitats for several snapper species worldwide. Yet the short-term dynamics in nursery habitat use of Lutjanidae remain poorly understood, with knowledge biased toward clear water, nonestuarine mangroves. Here, we document the effects of tidal-diel cycles and salinity on patterns in abundance and feeding of the yellow snapper, Lutjanus argentiventris, using samples collected from intertidal creeks in a macrotidal estuarine mangrove during 2009–2010 from Colombia, in the Tropical Eastern Pacific (TEP) region. Abundance and biomass were significantly higher in medium salinity versus low salinity creeks. Contrasting tidal-diel patterns of abundance-densities versus catch mass-biomass were due to a size-based intraspecific variation in mangrove use: fish 20 cm entered at night during both spring and neap tides. L. argentiventris had a generalist diet (mainly fish and porcellanid crabs). Fish <10 cm displayed a narrower diet breadth than larger size classes, with decreasing importance of fish size during ontogeny. The highest stomach fullness index values (especially of individuals <20 cm) during neap tide-daytime inundations contradicted the common assumption that snappers are nocturnal feeders and highlight the role of tidal-diel cycles in determining fish feeding preferences in macrotidal mangrove systems. Comparisons with other studies showed that habitat use and feeding patterns of this and other Lutjanids vary significantly according to size, tidal-diel dynamics, and mangrove settings, e.g., marine microtidal versus estuarine macrotidal systems. Therefore, generalized conclusions derived from a single mangrove setting should be drawn with caution.

MtDNA Analysis Suggests Local Origin of Pelagic-Stage Juvenile Green Turtles Collected in Japanese Coastal Waters

Understanding the distribution range across the life history of endangered animals is crucial for effective conservation and management planning. However, endangered migratory green turtles with straight carapace lengths (SCLs) of <35 cm have been rarely observed in the northwestern Pacific. Information on wild green turtles with an SCL of <35 cm in this region is therefore scarce. Historically, four individuals with an SCL of <35 cm from the Japanese coasts and an oceanic area in Japan have been reported. From 2011 to 2013, we collected nine turtles with an SCL of <35 cm from Japanese coasts and coastal waters. We reviewed the existing literature and compiled records of newly collected individuals and their mitochondrial deoxyribonucleic acid haplotypes. The combined total of 13 turtles had SCLs ranging from 6.2 to 28.0 cm. Molecular analyses of nine newly collected turtles indicated that most individuals had hatched at green turtle nesting sites on the Ogasawara Islands and islands in the Ryukyu Archipelago. These results suggest that early juvenile green turtles inhabit Japanese waters, and some turtles with an SCL of <35 cm appear to have remained in Japanese waters after leaving their natal beaches in Japan without drifting with the prevailing oceanic currents to central north or eastern Pacific regions. Although the sample size in the present study was small, this is a first step in constructing comprehensive conservation and management plans for green turtles in the northwestern Pacific.

First detection of the supersonic upward plasma flow structures in the early morning sector

AbstractWe present the first observations of the supersonic updrafting plasma drifts in the predawn sector. Two DMSP satellites quasi‐simultaneously detected two fast‐speed events: one of ~385 km spatial extension and with the maximum upward velocity of 1683 m/s appeared at ~3 LT, and the other of ~1500 km large with maximum speed of 1770 m/s occurred at ~5 LT. Both supersonic structures were observed above the eastern Pacific region, separated by ~35° of longitude in space and by 45 min in time. The events occurred at the recovery phase of the geomagnetic storm of 19 February 2014, during rapid oscillations of the interplanetary magnetic field Bz and the interplanetary electric field Ey components, which increased the eastward electric field in the equatorial nighttime ionosphere and triggered the generation of plasma irregularities. The storm time penetration electric fields seem to be the principal driver of the observed supersonic events.

Ionospheric response to the 2015 St. Patrick's Day storm: A global multi‐instrumental overview

AbstractWe present the first multi‐instrumental results on the ionospheric response to the geomagnetic storm of 17–18 March 2015 (the St. Patrick's Day storm) that was up to now the strongest in the 24th solar cycle (minimum SYM‐H value of −233 nT). The storm caused complex effects around the globe. The most dramatic positive ionospheric storm occurred at low latitudes in the morning (~100–150% enhancement) and postsunset (~80–100% enhancement) sectors. These significant vertical total electron content increases were observed in different local time sectors and at different universal time, but around the same area of the Eastern Pacific region, which indicates a regional impact of storm drivers. Our analysis revealed that this particular region was most concerned by the increase in the thermospheric O/N2 ratio. At midlatitudes, we observe inverse hemispheric asymmetries that occurred, despite the equinoctial period, in different longitudinal regions. In the European‐African sector, positive storm signatures were observed in the Northern Hemisphere (NH), whereas in the American sector, a large positive storm occurred in the Southern Hemisphere, while the NH experienced a negative storm. The observed asymmetries can be partly explained by the thermospheric composition changes and partly by the hemispherically different nondipolar portions of the geomagnetic field as well as by the IMF By component variations. At high latitudes, negative ionospheric storm effects were recorded in all longitudinal regions, especially the NH of the Asian sector was concerned. The negative storm phase developed globally on 18 March at the beginning of the recovery phase.

Patterns of Precipitation Change and Climatological Uncertainty among CMIP5 Models, with a Focus on the Midlatitude Pacific Storm Track*

Abstract Projections of modeled precipitation (P) change in global warming scenarios demonstrate marked intermodel disagreement at regional scales. Empirical orthogonal functions (EOFs) and maximum covariance analysis (MCA) are used to diagnose spatial patterns of disagreement in the simulated climatology and end-of-century P changes in phase 5 of the Coupled Model Intercomparison Project (CMIP5) archive. The term principal uncertainty pattern (PUP) is used for any robust mode calculated when applying these techniques to a multimodel ensemble. For selected domains in the tropics, leading PUPs highlight features at the margins of convection zones and in the Pacific cold tongue. The midlatitude Pacific storm track is emphasized given its relevance to wintertime P projections over western North America. The first storm-track PUP identifies a sensitive region of disagreement in P increases over the eastern midlatitude Pacific where the storm track terminates, related to uncertainty in an eastward extension of the climatological jet. The second PUP portrays uncertainty in a zonally asymmetric meridional shift of storm-track P, related to uncertainty in the extent of a poleward jet shift in the western Pacific. Both modes appear to arise primarily from intermodel differences in the response to radiative forcing, distinct from sampling of internal variability. The leading storm-track PUPs for P and zonal wind change exhibit similarities to the leading uncertainty patterns for the historical climatology, indicating important and parallel sensitivities in the eastern Pacific storm-track terminus region. However, expansion coefficients for climatological uncertainties tend to be weakly correlated with those for end-of-century change.

From the Pacific Ocean to the Mediterranean Sea: Watersipora arcuata, a new non-indigenous bryozoan in Europe

This study reports the first record of the cheilostome bryozoan Watersipora arcuata in the Mediterranean Sea, namely in a marina of the Ligurian Sea (Italy), during two monitoring surveys carried out in 2013 and 2014, representing to date the first European finding. The species, whose native origin is deemed to be the Tropical Eastern Pacific region, was already reported as being introduced to California, Australia, New Zealand and Hawaii, but not outside the Pacific Ocean. The genus Watersipora includes 13 species of encrusting bryozoans, difficult to distinguish using simple visual clues and usually requiring careful morphological measurements, with appropriate microscopy methods. A detailed taxonomic description of W. arcuata is provided here, in comparison with the similar species W. nigra and W. platypora.

A new species of the genus Typton Costa (Crustacea: Decapoda: Palaemonidae: Pontoniinae) from the eastern tropical Pacific.

A new species of commensal shrimp of the genus Typton from holothurians is described and illustrated. The specimens were collected from a single specimen of Holothuria (Halodeima) inornata Semper, 1868 at a depth of 7 m. This is the first record of an association between a shrimp of the genus Typton and echinoderms. With this record, five species of Typton are now known from the eastern Pacific region and four of them are found in the Mexican Pacific. In Typton granulosus sp. nov., the distal part of the outer margin of the uropodal exopod is serrated, a feature shared with T. fapespae Almeida et al., 2014, T. holthuisi De Grave, 2010, T. prionurus Holthuis, 1951, T. serratus Holthuis, 1951, and T. spongicola Costa, 1844. However, the new species can be separated from the other five species of the genus by several morphological characters.

Mitochondrial genome of the bullet tuna Auxis rochei from Indo-West Pacific collection provides novel genetic information about two subspecies

Previously morphological studies supported the division of the bullet tuna into the two subspecies, Auxis rochei rochei and A. rochei eudorax. As a cosmopolitan species, A. rochei rochei ranges in the Indo-West Pacific and Atlantic oceans, while A. rochei eudorax inhabits in eastern Pacific region. Here, we used the HiSeq next-generation sequencing technique to determine the mitochondrial genome (mitogenome) of A. rochei from Indo-West Pacific collection, and then compared our data with mitogenomic sequences of the Atlantic and eastern Pacific retrieved from NCBI database. Results showed the mitogenome of A. rochei from three geographic collections shared the same genes and gene order, similar to typical teleosts. Also, we examined a low level of nucleotide diversity among these mitogenomic sequences. Interestingly, nucleotide diversity of intra-subspecies (Atlantic versus Indo-West) was higher than that of inter-subspecies (Atlantic versus eastern Pacific, Indo-West versus eastern Pacific).