Apristurus manocheriani (Carcharhiniformes: Pentanchidae), a new species of catshark from the Southwest Indian Ocean

Abstract

A new species of catshark, Apristurus manocheriani n. sp., is described from 8 specimens collected from seamounts in the southwest Indian Ocean (SWIO). The new species is placed in the Apristurus spongiceps subgroup and is only the second known species in this subgroup occurring in the western Indian Ocean. Geographically, A. manocheriani is known only from the SWIO, while its two closest congeners are from distant locations: Apristurus albisoma Nakaya & Séret, 1999 occurs in the southwest Pacific Ocean and Apristurus aphyodes Nakaya & Stehmann, 1998 in the northeast Atlantic.

Full text

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Journal of the
Ocean Science Foundation
2021, Volume 38
Journal of the Ocean Science Foundation, 38, 13–26 (2021)
Apristurus manocheriani (Carcharhiniformes: Pentanchidae),
a new species of catshark from the Southwest Indian Ocean
JUSTIN A. CORDOVA
Pacic Shark Research Center, Moss Landing Marine Laboratories,
Moss Landing, CA 95039, USA
https://orcid.org/0000-0002-5138-8629 E-mail: jcordova@mlml.calstate.edu
DAVID A. EBERT
Pacic Shark Research Center, Moss Landing Marine Laboratories,
Moss Landing, CA 95039, USA
Research Associate, Department of Ichthyology, California Academy of Sciences,
55 Music Concourse Drive, San Francisco, CA. 94118, USA
Research Associate, South African Institute for Aquatic Biodiversity,
Private Bag 1015, Grahamstown, 6140, South Africa
https://orcid.org/0000-0003-4604-8192 E-mail: debert@mlml.calstate.edu
Abstract
A new species of catshark, Apristurus manocheriani n. sp., is described from 8 specimens collected from seamounts
in the southwest Indian Ocean (SWIO). The new species is placed in the Apristurus spongiceps subgroup and
is only the second known species in this subgroup occurring in the western Indian Ocean. Geographically, A.
manocheriani is known only from the SWIO, while its two closest congeners are from distant locations: Apristurus
albisoma Nakaya & Séret, 1999 occurs in the southwest Pacic Ocean and Apristurus aphyodes Nakaya &
Stehmann, 1998 in the northeast Atlantic.
Key words: taxonomy, ichthyology, Chondrichthyes, elasmobranch, seamounts, Southwest Indian Ridge.
Citation: Cordova, J.A. & Ebert, D.A. (2021) Apristurus manocheriani (Carcharhiniformes: Pentanchidae), a
new species of catshark from the Southwest Indian Ocean. Journal of the Ocean Science Foundation, 38, 13–26.
doi: https://doi.org/10.5281/zenodo.5081131
urn:lsid:zoobank.org:pub:AC333F16-ACC8-47DD-8FA6-BB8030C7DBE4
Date of publication of this version of record: 7 July 2021

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Introduction
The genus Apristurus Garman, 1913 (Chondrichthyes: Pentanchidae) comprise one of the most species-rich
shark genera with 39 valid species (Weigmann 2016, White et al. 2017). The genus is divided into three subgroups
based on morphological and meristic characters (Nakaya & Sato 1999), egg case morphology (Flammang
et al. 2007), and molecular data (Sato 2000, Iglesias et al. 2005). The three subgroups are referred to as the
longicephalus, brunneus and spongiceps subgroups. The longicephalus subgroup can be distinguished from the
other two subgroups by a very long, narrow, and slender snout; its length from snout tip to anterior nostrils
is greater than 6.4% total length (TL). The other two subgroups, referred to as the spongiceps and brunneus
subgroups, have relatively shorter snouts, with their lengths being less than 6.4% total length (TL). The spongiceps
subgroup is separable from the brunneus subgroup by having a more stout vs. slender body, lower labial furrows
equal to or longer than the uppers, lower spiral valve counts (7–12 vs. 13–22), and a continuous vs. discontinuous
supraorbital sensory canal (Nakaya & Sato 1999). Also, the egg cases of the spongiceps group lack tendrils at their
corners, while those of the brunneus subgroup have long coiled tendrils (Flammang et al. 2007).
Members of the genus Apristurus are found in all oceans, including Arctic, but not Antarctic, waters, mostly at
depths from about 200–2200 m, and on continental and insular slopes, deep-sea ridges, seamounts, and trenches
(Ebert & Winton 2010, Kawauchi et al. 2014). Many Apristurus species appear to be endemic, while others appear
to have a wider distribution. The majority of species are found in the western Pacic (at least 20 species), followed
by the western Atlantic with 8 species (Ebert et al. 2021a). The western Indian Ocean (WIO) is reasonably well
represented, with 6 Apristurus species, including: A. longicephalus Nakaya, 1975; A. breviventralis Kawauchi,
Weigmann & Nakaya, 2014; A. indicus (Brauer, 1906); A. melanoasper Iglésias, Nakaya & Stehmann, 2004;
A. microps (Gilbert, 1922); and A. saldanha (Barnard, 1925). Of these 6 species, the only spongiceps subgroup
representative is A. microps, whose distribution extends just into the southwest Indian Ocean (SWIO) off the
south coast of South Africa (Ebert 2013, Kawauchi et al. 2014, Ebert et al. 2021b).
During two surveys conducted in 2012 and 2014 along the Southwest Indian Ridge (SWIOR), specimens
of an Apristurus species were collected with characteristics associated with the spongiceps subgroup. Upon closer
examination, it was found to be distinct from all other known spongiceps subgroup species and we describe it
here. This paper is part of a series describing new species and revising chondrichthyan taxa from the SWIO.
Materials and Methods
Morphometric measurements were taken in full on the holotype and 7 paratypes following the methodology
and terminology proposed by Nakaya et al. (2008) for the genus Apristurus. Morphometric values to the nearest
millimeter (mm) are presented as ratios of the total length (TL). Meristics, including tooth and vertebral counts,
were taken from the type series.
To identify differences between the new species and its two closest congeners, morphometric measurements
expressed as %TL were assessed using non-metric multidimensional scaling (nMDS) ordination (Clarke &
Gorley 2006). In this analysis, similar morphometric characters are plotted on a graph close together in ordination
space, while dissimilar ones fall far apart (Gotelli & Ellison 2013, White et al. 2013). The different assemblages
identied using nMDS represent different species. To assess if there was a statistical difference in the multivariate
morphometric data collected for each group, a Permutational Multivariate Analysis of Variance (PERMANOVA)
was conducted. No additional transformations were necessary before calculation of the resemblance matrix since
morphological data were expressed as percentages. Data were visually inspected for normality using a Normal
Quantile-Quantile plot with 95% Condence intervals and this assessment indicated that the morphometric data
were normally distributed. Similarity Percentages (SIMPER) analysis associated with the nMDS was conducted
to provide insight into which traits most contributed to differences among groups using the Vegan package in R
(Oksanen et al. 2020).
All type specimens are deposited into the sh collection at the California Academy of Sciences Ichthyology
(CAS-ICH). Comparative material was examined from the Commonwealth Scientic and Industrial Research
Organization, Division of Marine and Atmospheric Research (CSIRO), Moss Landing Marine Laboratories
(MLML), Museum of Comparative Zoology (MCZ), South African Institute for Aquatic Biodiversity (SAIAB),

15
Iziko South African Museum (SAM), Muséum national d’Histoire naturelle, Paris (MNHN), Scripps Institution
of Oceanography (SIO), United States National Museum of Natural History, Smithsonian Institution, Washington,
DC (USNM), University of Washington (UW), and the Zoological Museum Hamburg (ZMH). Institutional
abbreviations follow Sabaj (2019).
Figure 1. Apristurus manocheriani, n. sp., holotype, lateral view, adult male, 558 mm TL (CAS-ICH 247255) before
preservation (A) and after preservation (B); scale bar = 5 cm.
Genus Apristurus Garman, 1913
Apristurus Garman, 1913: 96
Type species. Scyliorhinus indicus Brauer, 1906, by original designation.
Apristurus manocheriani, new species
Manocherian’s Catshark
urn:lsid:zoobank.org:act:61EB269F-189D-4367-A3DF-F85CA05F82AA
Figures 1–7, Table 1
Holotype. CAS-ICH 247255, mature male, 558 mm TL, SWIOR, Indian Ocean, -35.133°, 53.700°, 89–1240
m, 30 April 2014 (taken as bycatch in deep-sea trawl for Alfonsino (Beryx spp.) and Orange Roughy (Hoplostethus
atlanticus)).
Paratypes. (7 specimens) CAS-ICH 247256, mature male, 536 mm TL, Indian Ocean, SWIOR, -35.167°,
54.283°, 620–920 m, 1 April 2014; CAS-ICH 247257, female, 476 mm TL, Indian Ocean, Walters Shoal, -34.667°,
44.250°, 1000–1300 m, 8 March 2012; CAS-ICH 247258, Female 467 mm TL, Indian Ocean, SWIOR, -35.167°,
53.667°, 900–1100 m, 8 March 2012; CAS-ICH 247259, female, 485 mm TL, Indian Ocean, Walters Shoal,
-34.667°, 44.250°, 89–1240 m, 8 March 2012; CAS-ICH 247260, female, 480 mm TL, Indian Ocean, Walters
Shoal, -34.417°, 44.333°, 1200–1300 m, 10 March 2012; CAS-ICH 247261, female, 495 mm TL, Indian Ocean,
SWIOR, -35.167°, 54.283°, 620–920 m, 1 April 2014; CAS-ICH 247262, mature male, 491 mm TL, Indian
Ocean, SWIOR, -39.00°, 46.50°, 800–1200 m, 4 April 2012.

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Diagnosis. A new species in spongiceps subgroup of Apristurus, as dened by Nakaya & Sato (1999),
distinguished from all congeners by a combination of characteristics: an overall uniformly whitish “porcelain”
colored body with lighter colored anal and caudal-n margins and a distinct white spot on tail tip vs. a uniform
dark brown to grayish, or blackish, body coloration, variably with blotches, ecks, spots, or squiggles, in all
other spongiceps subgroup species (except A. albisoma and A. aphyodes with similar light coloration, but subtle
differences); clasper hooks present vs. absent; oral papillae absent or sparsely covering oral cavity roof vs. distinct
and densely covering oral cavity roof; dorsal caudal margin with widely spaced, non-overlapping dermal denticles
vs. closely spaced, overlapping denticles; lower tooth counts, i.e. 46–57 in upper jaw and 44–50 in lower jaw vs.
56–71 and 49–70 respectively.
Description. (proportional measurements expressed as percentage of total length (TL) for holotype followed
by range for 7 paratypes in parentheses) Body cylindrical, elongate, relatively stout to about pelvic ns, tapering
posteriorly (Fig. 1); abdomen relatively long
with pectoral–pelvic n space longer than
anal-n-base length and rst and second
dorsal-n origins length; posterior body
behind pelvic ns compresses laterally to
caudal origin. Head depressed, length about
twice maximum head width (Fig. 2). Snout
bell-shaped in dorsoventral view, moderately
long, tip rounded, tapering evenly. Pre-outer
nostril length slightly greater than internarial
width and about 0.6 (0.5–0.7) times
interorbital width. Pre-oral length less than
pre-orbital length, about 1.9 (1.7–2.3) times
internarial width, less than mouth width, and
about 1.1 (0.9–1.3) times interorbital width.
Pre-orbital length about 1.4 (1.3–1.9) times
interorbital width and about 3.2 (3.2–4.3)
times orbit length. Internarial width about
1.3 (1.3–1.4) times orbit length, about 1.2
(1.2–1.5) times nostril length. Supraorbital
sensory canal continuous. Nostrils large,
expanding obliquely inwards from snout
edge; nostril length about 0.5 (0.4–0.5) times
pre-inner nostril length, about 0.8 (0.6–
0.8) times internarial width, and about 1.1
(0.9–1.1) times orbit length. Nostril–mouth
space about 0.4 (0.3–0.6) times internarial
width. Mouth broadly arched in an inverted
U-shape, with well-developed labial furrows
at mouth corners; upper labial furrows about
1.1 (1.0–1.1) times longer than lower ones.
Oral papilla not present (mostly) or poorly
developed. Upper labial furrows not reaching
midpoint between mouth corner and posterior
margin of nostril. Orbits oval, relatively small,
without distinct subocular folds; orbit length
less than internarial width and about 0.8
(0.7–0.8) times interorbital width. Spiracles
small, located closely behind and just below
Figure 2. Apristurus manocheriani, n. sp., head of holotype, lateral (top),
ventral and dorsal views; scale bar = 3 cm.

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TABLE 1
Proportional measurements of type specimens of Apristurus manocheriani
n. sp. as percentages of total length
holotype paratype
max
paratype
min holotype paratype
max
paratype
min
Total length (mm) 558 536 467 P1 tip to P2 origin 13.6 15.2 10.8
PreD2–insertion length 73.8 73.7 70.5 P1–P2 origins 25.1 26.3 21.4
PreD2–origin length 67.9 67.9 64.8 P1–P2 insertions 26.9 26.9 23.4
PreD1–insertion length 59.1 59.6 57.8 P2–anal space (ceratotrichia) 7.5 8.8 5.9
PreD1–origin length 53.0 55.9 52.1 P2–anal origins (ceratotrichia) 14.9 16.1 12.8
PreP1 length 22.9 26.4 21.2 D1 length 8.2 9.3 8.0
PreP2 length 48.4 48.1 46.0 D1 base length 5.2 5.9 4.7
Pre–vent length 50.9 50.9 48.3 D1 height 2.2 2.3 1.8
Pre–anal length (ceratotrichia) 61.8 62.3 58.7 D1 free lobe length 3.2 3.5 2.5
Pre–anal length (incl. muscle) 60.8 59.2 56.4 D2 length 9.0 10.9 8.5
Pre–caudal length 73.8 74.5 70.5 D2 base length 5.7 6.1 5.1
Pre–branchial length 18.3 19.0 16.4 D2 height 3.0 2.9 2.1
Pre–spiracular length 13.1 14.7 13.3 D2 free lobe length 3.0 4.7 3.5
Pre–orbital length 9.7 12.9 9.7 P1 base length 6.5 8.1 6.3
Pre–outer nostril length 3.8 5.0 3.7 P1 anterior margin 9.3 11.3 8.4
Pre–inner nostril length 5.9 6.8 5.5 P1 posterior margin 7.3 6.7 5.4
Pre–oral length 7.3 8.5 7.1 P1 inner margin 5.6 7.1 5.2
Head length 22.0 23.8 22.0 P1 width 7.2 6.9 5.6
Head height 9.0 10.1 6.7 P2 anterior margin 2.7 5.4 2.9
Head width (mouth corners) 10.0 10.8 8.7 P2 length 8.2 10.9 8.2
Head width (max) 10.8 11.7 8.9 P2 base length 6.8 8.6 6.9
Mouth width 7.9 9.4 7.6 P2 posterior margin 5.9 6.7 5.0
Mouth length 5.4 6.1 4.6 P2 inner margin 0.9 2.4 0.9
Internarial length 3.9 4.4 3.7 Anal base length (ceratotrichia) 12.5 13.7 9.9
Upper labial furrow 2.7 3.1 2.2 Anal base length (muscle) 14.3 16.2 12.6
Lower labial furrow 2.5 3.1 2.0 Anal anterior margin 7.3 9.7 6.5
Orbit length 3.0 3.4 2.9 Anal posterior margin 7.3 7.9 6.0
Orbit height 1.6 1.9 1.3 Anal height (muscle) 5.2 5.9 4.0
Nostril length 3.2 3.1 2.5 Anal inner margin 0.5 1.3 0.2
Nostril mouth–space 1.4 2.2 1.4 Caudal peduncle height 3.9 4.4 3.5
Interorbital width 6.8 8.0 6.4 Caudal length 27.8 30.7 26.5
First gill height 3.6 3.5 2.6 Caudal height 7.7 8.4 7.4
Third gill height 3.4 3.7 2.8 Caudal preventral margin 9.5 10.1 9.0
Fifth gill height 1.6 2.4 1.9 Caudal postventral margin 15.8 15.5 13.6
D1–D2 space 9.5 9.3 8.1 Caudal terminal lobe height 2.3 2.6 1.7
D1–D2 origins 14.2 14.4 13.3 Caudal terminal lobe length 3.6 5.5 4.3
D1–D2 insertions 15.2 14.4 13.1 Caudal terminal lobe post. margin 2.9 3.9 2.1
P1–P2 space 19.2 19.6 17.6 Clasper outer length 5.4 5.5 5.2
Clasper inner length 9.0 9.7 9.4

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horizontal axis at posterior rim of orbits. Five small gill slits present, rst three similar in height; fourth gill slit
located above pectoral n origin, slightly smaller than rst three; fth gill slit smallest. Gill septa visible, without
projections, densely covered with ne dermal denticles.
Pectoral ns relatively small, subangular, and broadly rounded posteriorly; length of anterior margin about
equal to or less than one-third distance between pectoral–pelvic-n origins; right and left ns separated by a space
nearly equal to mouth width. Pelvic ns moderate in size, length about 1.6 (1.5–2.0) times anal n height, slightly
less than distance between pectoral–pelvic-n origins. Dorsal ns similar in shape and size. First-dorsal-n origin
slightly posterior to pelvic-n insertion (axil); insertion slightly anterior to level of anal-n origin. Second-dorsal-
n origin about mid-point of anal-n base; insertion slightly anterior to anal-n insertion; base length about two-
thirds pectoral–pelvic space length. Anal n high, broadly rounded, base length more than twice height; anal and
caudal ns separate only by a notch. Caudal n slender; ventral lobe high; apex of ventral lobe rather angular;
subterminal notch distinct; terminal lobe long, about 1.5 (1.9–3.1) times as long as high. Caudal peduncle high,
height less than one-half interdorsal space, nearly equal to internarial width.
Teeth numerous and large (Fig. 3); similar in upper and lower jaw; upper anteriors with long, robust, central
cusp, anked by one or two acutely pointed lateral cusps on each side, less than one-half height of central cusp;
upper laterals with long central cusp anked by two successively smaller cusps on each side, about one-half or
less than height of preceding cusp; lower teeth similar to uppers, with central cusp of anteriors having one or two
lateral cusps on each side, and laterals anked by two lateral cusps on each side. Sexual dimorphism apparent:
adult male jaws more pronounced than adult females, very strongly arched, adult female jaws more weakly
arched. Tooth counts in rst row of upper jaw 51 (46–57) and in rst row of lower jaw 49 (44–50).
Dermal denticles (Fig. 4) on dorsolateral side of body erect, small, overlapping each other, tricuspidate with a
long, ridged central cusp anked on each side by a much smaller lateral cusp; outer surface of denticles structured
by reticulations. No observed difference between similar-sized female and male specimens; smaller individuals
Figure 3. Apristurus manocheriani, n. sp., teeth of holotype, A: upper anterior tooth, B: upper lateral tooth, C: lower anterior
tooth, D: lower lateral tooth.

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unavailable. Caudal-n dorsal margin without
enlarged dermal denticles, shape similar to
ank denticles, but more widely spaced.
Claspers (Fig. 5) short, robust, tapering
posteriorly to tip, nearly reaching anal-n-
muscle origin; dermal denticles cover entire
ventral side, partially on dorsal area, and almost
entire claspers; clasper hooks present, 5 visible
on lateral side of exorhipidon; pseudosiphon
distinct, circle-shaped, and deep; rhipidon cover
reduced, not covering center of the clasper
groove; pseudopera large, deep, only visible if
clasper extended; exorhipidon at, simple oval
shaped; terminal dermal cover present at distal
tips of clasper.
Vertebral counts: monospondylous pre-
caudal (MP) 35 (32–35); diplospondylous
precaudal (DP) 29 (25–29); total precaudal
counts 64 (60–64); caudal 52 (49–54); total
vertebral counts 116 (112–116).
Meristic features: (following counts
are for holotype, then range of paratypes in
parentheses, if different) Dorsal-n elements
X,15 (15 or 16, most 16; when 15, a deeply
divided last ray); anal-n elements III,7, all Figure 4. Apristurus manocheriani, n. sp., paratype, adult male, 491
mm TL (CAS-ICH 247262); dermal denticles of dorsolateral side.
Figure 5. Apristurus manocheriani, n. sp., dorsal view of left and right claspers of holotype: CRH: cover rhipidion; CLH:
clasper hooks; DD: dermal denticles; ERH: exorhipidion; PP: psuedopera; PSH: pseudosiphon; RH: rhipidion; TDC:
terminal dermal cover; scale bar = 1 cm.

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dorsal-n and anal-n rays branched, last sometimes to base; pectoral-n rays 18 or 19 (usually 19), about two
upper and lower rays unbranched; pelvic-n rays I,5; principal caudal-n rays 8+7, middle 13 branched; pored
lateral-line scales 50 or 51 (48–54); scales above rst lateral-line scale to base of second-dorsal-n spine 4 1/2;
scales above lateral-line apex to base of middle dorsal-n spines 3 1/2; scales below lateral line to origin of anal
n about 15; circumpeduncular scales about 26; gill rakers 10+26 (9–11 + 24–27); branchiostegal rays 7.
Color. (Figs. 1A & B) Prior to preservation, body uniformly “porcelain” whitish with a slight pinkish tinge,
ns mostly similar except for white edges along posterior margins of anal and caudal n and a prominent to faint
white caudal-n tip; anterior margins of dorsal ns thinly blackish, rst-dorsal-n posterior margin and free rear
tip white, second-dorsal-n posterior margin blackish. After preservation, body and ns become dark gray to
brownish, except for white n edges still distinct, but may eventually fade with time.
Size. A moderate-sized Apristurus species, A. manocheriani reaches a maximum total length of at least 558
mm for males and 495 mm for females. All three males were mature, with a minimum mature size of 491 mm TL.
Females ranged in size from 467–495 mm TL, but were not examined internally for maturity.
Distribution. Based on the available material, the new species is presently known only from the SWIO on
the southern end of the Madagascar ridge at Walters Shoal, in an area from approximately -34.417°, 44.333° to
-34.667°, 44.250°, and on the SWIOR in an area from approximately -35.133°, 53.700° to -35.167°, 54.283° and
at -39.00°, 46.50° (Fig. 6). Specimens were collected from 89–1,300 m deep, although mostly deeper than 620
m, in both bottom and midwater trawls. The shallowest catch record of the new species, possibly at 89 m, came
from a midwater trawl.
Figure 6. Distribution map of Apristurus manocheriani n. sp. specimens collected from the Madagascar ridge at Walters
Shoal and on the SWIOR. The holotype is represented by a star and paratypes by circles.

21
Etymology. The new species is named for Greg Manocherian in recognition of his strong commitment to and
passion for shark conservation and research. The proposed English common name is Manocherian’s Catshark.
Comparisons. Apristurus manocheriani n. sp. is assigned to the spongiceps subgroup as dened by Nakaya &
Sato (1999) based upon its relatively stout body, upper and lower labial furrows being approximately equidistant
in length, a pre-outer nostril length shorter than interorbital width, a continuous sensory canal, and the low number
of spiral valve turn counts ranging from 7–12. Presently, there are 13 species represented in the spongiceps
subgroup including A. albisoma Nakaya & Séret, 1999; A. ampliceps Sasahara et. al., 2008: A. aphyodes Nakaya
& Stehmann, 1998; A bucephalus White et al., 2008; A. fedorovi Dolganov, 1985; A. kampae Taylor, 1972; A.
manis Springer, 1979; A. microps Gilchrist, 1922; A. pinguis Deng, Xiong & Zhan, 1983; A. profundorum Goode
& Bean, 1896; A. riveri Bigelow & Schroeder, 1944; A. spongiceps Gilbert, 1905; and A. stenseni Springer, 1979.
The new species can be separated from all but two spongiceps subgroup species based on its overall whitish
body coloration, lighter anal and caudal-n margins, and distinct white spot on its tail tip. Nakaya & Séret (1999)
stated that white to light grayish coloration in fresh specimens is not found in many species within the spongiceps
subgroup. Furthermore, they found that coloration was a useful characteristic to separate most spongiceps
subgroup species. In fact, most members of this subgroup have a uniform dark brown to grayish or blackish body
coloration, including A. ampliceps, A bucephalus, A. fedorovi, A. kampae, A. manis, A. microps, A. pinguis, A.
profundorum, A. riveri, A. spongiceps, and A. stenseni. In addition, 6 of these species (A. fedorovi, A. microps,
A. profundorum, A. riveri, A. spongiceps, and A. stenseni) have no distinct markings such as blotches, ecks,
spots, squiggles or lighter n edges. In addition to their dark body coloration, three species (A. ampliceps, A.
bucephalus, and A. pinguis) have blotches, ecks, spots, or squiggles, while two species have lighter n edges (A.
kampae and occasionally A. manis). Only A. albisoma and A. aphyodes have light body coloration most similar
to A. manocheriani.
Geographically, 4 spongiceps subgroup species occur in the Indian Ocean, with three (A. ampliceps, A.
bucephalus, and A. pinguis) occurring in the eastern Indian Ocean, and only A. microps found the SWIO off
South Africa. All 4 species can be separated from the whitish A. manocheriani by their darker body coloration.
Furthermore, the closest biogeographic spongiceps subgroup congener, A. microps has a crest of enlarged dermal
denticles along the upper caudal margin, while A. manocheriani lacks a crest of enlarged denticles. The two
closest congeners to A. manocheriani based on their whitish body coloration both occur outside the Indian Ocean.
Apristurus albisoma is found in the southwest Pacic Ocean along the Norfolk and Lord Howe Ridges extending
from off New Caledonia to the Australian exclusive economic zone (Nakaya et al. 2015), while A. aphyodes is
known from the northeast Atlantic from Iceland to the northern Bay of Biscay (Ebert & Dando 2020).
In addition to biogeography, A. manocheriani can be separated from the two light-colored spongiceps subgroup
species by a combination of morphological and meristic characteristics. Morphologically, A. manocheriani have
clasper hooks present vs. absent in A. albisoma and A. aphyodes; widely-spaced dermal denticles along the
dorsal caudal margin vs. closely packed denticles; oral papillae mostly absent or if present greatly reduced and
sparsely covering the oral cavity roof vs. distinct, nger-like, papillae densely covering the oral cavity roof; tooth
counts for upper (46–57) and lower (44–50) jaws slightly lower vs. higher counts for A. albisoma upper (56–71)
and lower 61 (54–70) jaws, and for A. aphyodes upper (56–68) and lower (49–64) jaws; and monospondylous
precaudal counts are slightly lower (32–35) vs. A. albisoma (34–36) and A. aphyodes (34–37).
Apristurus manocheriani can further be separated from A. albisoma by subtle differences in body coloration.
A. manocheriani is uniformly “porcelain” whitish with a pinkish tinge, with ventral head, body, and gill area
coloration similar to dorsal surface vs. uniform white without a pinkish tinge, with ventral head, body, and gill
area noticeably darker than the dorsal surface; n margins distinctly white along anal n margins vs. dark margins
along anal n; caudal-n margins white with a prominent white spot at tip vs. no distinct lighter or blackish n
margins or prominent white spot at caudal-n tip. Morphologically, A. manocheriani has a slightly longer pre-
orbital length times inter-orbital width 1.3–1.9 vs. 0.9–1.4 for A. albisoma; a slightly longer caudal terminal lobe
length times its height 1.9–3.1 vs. 1.4–2.1; shorter head width at mouth corners 8.7–10.8 vs. 11.8–13.7; slightly
longer orbit length 2.9–3.4 vs. 2.3–3.1; slightly shorter interorbital width 6.4–8.0 vs. 8.1–8.7; longer interdorsal
space 8.1–9.5, pectoral–pelvic space 17.6–19.6, and pelvic–anal space 5.9–8.8 vs. 6.7–8.4, 13.5–17.7, and 4.1–
6.6, respectively.

22
Apristurus manocheriani can be distinguished from A. aphyodes by differences in body coloration. The body
coloration of A. aphyodes is a uniform whitish to lead or pale gray, with distinctly darker ns distally and no white
spot at the caudal tip. This is in contrast to the light “porcelain” colored A. manocheriani with its distinct white
posterior anal and caudal-n margins and prominent white spot on its caudal tip. A. manocheriani differs from A.
aphyodes morphologically by having a noticeably smaller second dorsal n vs. similar-sized dorsal ns; anal n
being more broadly rounded vs angular; mouth strongly arched vs. broadly rounded; mouth width wider 7.6–9.4
vs. 6.7–7.7 and length longer 4.6–6.1 vs. 4.1–4.4; upper labial furrows extending past lower symphysis of mouth
vs. not extending past lower mouth symphysis; head width slightly smaller 8.9–11.7 vs. 11.1–12.6; shorter pre-
orbital length times inter-orbital width 1.3–1.9 vs. 2.9–3.1; caudal terminal lobe longer, its length times its height
1.9–3.1 vs. 1.7–1.9.
The MDS analysis of A. manocheriani with its two closest morphological congeners A. albisoma, and A.
aphyodes showed clear differences between species, visualized as three distinct clustered groups (Fig. 7). The
PERMANOVA output showed a modest percentage of variation in distances is explained by species grouping
(df=2, F statistic=3.8693, p=0.001), which rejects the null hypothesis and concludes that there are differences
between these three species. The data met assumptions that the variance in measures was homogenous among
Figure 7. Non-metric multi-dimensional scaling (nMDS) plot comparing the morphological traits of Apristurus manocheriani
n. sp., A. aphyodes, and A. albisoma.

23
groups, so the differences are due to differences in their centroids rather than from differences in variances of the
measurements (df=2, F-statistic=1.4184, p=0.271). SIMPER analysis revealed the measurements most responsible
for differences between A. manocheriani compared to A. albisoma, in order of importance, is pectoral–pelvic-n
origins length, head width at maximum length, head width at mouth corners, interorbital length, and interdorsal
n space. SIMPER analysis of A. manocheriani compared to A. aphyodes revealed, in order of importance, that
pre-rst dorsal-n origin length, head height, pre-vent length, mouth length, and mouth width were the most
signicant values.
Key to the Western Indian Ocean genus Apristurus
(modied from Ebert (2013) and Kawauchi et al. (2014))
1a. Snout very slender and elongate; length of pre-outer nostril much greater than interorbital width (Seychelles,
Mozambique, and Western Pacic) (longicephalus subgroup)....................................... A. longicephalus
1b. Snout relatively wide and short; length of pre-outer nostril length much shorter than interorbital width .......... 2
2a. Body relatively slender; upper labial furrows longer than lowers; supraorbital sensory canals discontinuous;
spiral valve counts high (13–22) (brunneus subgroup)............................................................................. 3
2b. Body relatively stout; upper labial furrows as long as or shorter than lower ones; supraorbital sensory canals
continuous; spiral valve counts low (7–12) (spongiceps subgroup).............................................................. 6
3a. First dorsal-n origin behind pelvic-n insertion (Socotra Islands, Gulf of Aden) ............. A. breviventralis
3b. First dorsal-n origin above pelvic-n base ........................................................................................................... 4
4a. Pectoral–pelvic space about as long as anal-n base (ceratotrichia) (Somalia, Gulf of Aden, Oman) .........A. indicus
4b. Pectoral–pelvic space about as long as anal-n base (ceratotrichia) ........................................................................... 5
5a. Interdorsal space very long, about equal to prespiracular head; 13–16 spiral valves (South Africa, SE
Atlantic) .................................................................................................................................... .A. saldanha
5b. Interdorsal space shorter, much less than prespiracular head, 19–23 spiral valves (Madagascar Ridge, North and
SE Atlantic, Eastern Indian Ocean, southwest Pacic Ocean) ................................................ .A. melanoasper
6a. Body coloration uniformly dark brown, brownish gray, to purplish-black, no distinctive lighter or darker
n margins; enlarged crest of dermal denticles along upper caudal margin (South Africa, SE Atlantic,
North Atlantic) .................................................................................................................. .A. microps
6b. Body coloration uniformly whitish, with lighter anal and caudal posterior margins; no enlarged crest of dermal
denticles along upper caudal margins (Madagascar Ridge) .......................................... .A. manocheriani n. sp.

24
Other material examined:
Apristurus albisoma (9 specimens): Holotype: MNHN 1997-3366, male, 573 mm TL, off New Caledonia,
25° 47´ 77” S, 167° 11´ 52” E to 25° 50´ 65” S, 167° 12´ 47” E, 1317–1383 m. Paratypes: (8 specimens) MNHN
1997-3359, male, 595 mm TL, MNHN 1997-3361, female, 566 mm TL, MNHN 1997-3365, male, 582 mm TL,
all off New Caledonia, 25° 47´ 77” S, 167° 11´ 52” E to 25° 50´ 65” S, 167° 12´ 47” E, 1317–1383 m; MNHN
1997-3368, male, 540 mm TL, MNHN 1997-3370, male, 592 mm TL, off New Caledonia, 25° 34´ 29” S, 167°
25´ 08” E to 25° 34´ 48” S, 167° 21´ 74” E, 1132–1160 m; MNHN 1997-3360, female, 548 mm TL, off New
Caledonia, 25° 41´ 99” S, 167° 25´ 60” E to 25° 42´ 98” S, 167° 22´ 43” E, 1230–1268 m; MNHN 1997-3383,
male, 547 mm TL, off New Caledonia, 23° 56´ 56” S, 161° 53´ 14” E to 23° 58´ 96” S, 161° 55´ 15” E, 1034–1056
m; MNHN 1997-3358, male, 376 mm TL, off New Caledonia, 23° 40´ 02” S, 168° 03´ 15” E to 23° 40´ 04” S,
168° 05´ 33” E, 935–1100 m.
Apristurus ampliceps (4 specimens): Paratype: CSIRO H 1009-05, male, 821 mm TL, north-west of Sandy
Cape, Tasmania, Australia, 41°12–16′ S, 143° 56′–58′ E, 1110–1190 m, 11 August 1987. Non-types: CSIRO
H1009-04, adult male, northwest of Sandy Cape, Tasmania, 41° 16.05′ S, 143° 58 E, 1110–1190 m, 11 August
1987; CSIRO H1009-06, adult female, northwest of Sandy Cape, Tasmania, 41°16.05´ S, 143° 58´ E, 1110–1190
m, 11 August 1987; CSIRO H5220-01, adult female, South Tasman Rise, Tasman Sea, 47° 09´ S, 148° 43´ E, 1100
m, 16 February 1999.
Apristurus aphyodes (7 specimens): Holotype: ZMH 24878 [ex ISH 71-1981], adult male, 521 mm TL, Lousy
Bank, Eastern North Atlantic, 58° 42.8´ N, 13° 37.6´ W, 1200–1240 m. Paratypes (6 specimens): ZMH 24877 [ex
ISH 49-1981], female, 494 mm TL, Lousy Bank, Eastern North Atlantic, 60° 20.5´ N, 14° 44´ W, 1800 m; ZMH
24870 [ex ISH 124-1981], male, 478 mm TL, northern Bay of Biscay, Eastern North Atlantic, 49° 37.7´ N, 12°
35.1´ W, 1740–1750 m; ZMH 24872 [ex ISH 17-1974], adult female, 532 mm TL, Lousy Bank, Eastern North
Atlantic, 60° 42´ N, 12° 57´ W, 1014–1024 m; ZMH 24874 [ex ISH 187-1983], female, 408 mm TL, Porcupine
Seabight, Eastern North Atlantic, 49° 31.9´ N, 12° 34.6´ W, 1487–1491 m; ZMH 24880 [ex ISH 807-1974], male,
315 mm TL, Porcupine Seabight, Eastern North Atlantic, 51° 30´ N, 12° 48´ W, 1500–1525 m; ZMH 24875 [ex
ISH 24-1981], juvenile female, 209 mm TL, Bill Bailey Bank, Eastern North Atlantic, 59° 56.8´ N, 10° 03.8´ W,
1138–1140 m.
Apristurus fedorovi (2 specimens): H3994-01 female, east of Iwate Prefecture, Japan, 40° 04.5´ N, 142°
43.5´ E, 1095–1100 m, 25 September 1978; H3995-01 adult male, east of Aomori Prefecture, Japan, 40° 47.6´ N,
142°16.7´ E, 920–948 m, 11 September 1978.
Apristurus kampae (14 specimens): Holotype: SIO70-248, female 340 mm TL, Gulf of California, Mexico,
27° 22.4´ N, 111° 20.5´ W to 27° 10.1´ N, 111° 29.6´ W, 1830–1888 m, 14 June 1970. Non-types (13 specimens):
SIO70-299, juvenile male, 189 mm TL, Galapagos Islands, Isla San Salvador 0° 7.5´ S, 90° 54.0´ W, 490 m, 25
October 1970; SIO88-98, adult male, 562mm TL, S of Morro Bay, 1 35° 12.9´ N–121° 40.4´ W, 109–1106m, 29
March 1988; SIO92-133, adult female,, 540 mm TL, 35° 26.8´ N–121° 40.8´ W, 1092m, 31 March 1988; SIO85-
70, adult male, 560mm TL, Monterey Co., Point Sur, 36° 22.1´ N–122° 13.4´ W, 988-1006 m, 13 March 1985;
CAS 58482, adult female, 543 mm TL, 1381–1408 m, 36° 115´ 18” N, 122° 122´ 54” W, 8 December 1985;
CAS 58771, adult female, 559 mm TL, 1008–1171 m, 35° 144´ 36” N, 122° 103´ 48” W, 7 December 1985; UW
045629, adult female,, 37° 115´ 1.5” N, 123° 108´ 25.89” W, 31 October 1997; UW 045634, adult female, 528
mm TL, 1253 m, 37° 113´ 22.3” N, 123° 110´ 30.3” W, 24 September 1997; UW045634, adult female, 550mm
TL, 1253m, 37° 113´ 22.3” N, 123° 110´ 30.3” W, 24 September 1997; UW046041, adult female, 539 mm TL,
1132 m, 34° 131´ 31.4” N, 121° 114´ 54.9” W, 7 November 2001; MLML uncatalogued (AK015) adult female,
555 mm TL, 1005–1010 m, 34° 141´ 52” N, 121° 129´ 59” W, 26 July 2002; MLML uncatalogued (AK016) adult
female, 589 mm TL, 1110–1155 m, 36°114´ 53” N, 122° 117´ 13” W, 15 September 2002; MLML uncatalogued
(AK018) adult female, 548 mm TL, 1044–1054 m, 37° 115´ 13” N, 123° 107´ 32” W, 14 September 2002.
Apristurus microps (5 specimens): ZMH105158, female 356 mm TL Southwestern Coast of South Africa;
SAIAB 26318, 465 mm TL, R/V Africana cruise 046, West Coast Demersal Survey, bottom trawl, station A4361
046 E12, 31° 59.8´ S, 15° 56.2´ E, 850 m, 17 July 1986; SAIAB 26319, 504 mm TL, R/V Africana cruise 046,
West Coast Demersal Survey, bottom trawl, station A4361 046 E12, 31° 59.8´ S, 15° 56.2´ E, 850 m, 17 July

25
1986; SAIAB 26320, 511 mm TL, R/V Africana cruise 046, West Coast Demersal Survey, bottom trawl, station
A4361 046 E12, 31° 59.8´ S, 15° 56.2´ E, 850 m, 17 July 1986; SAIAB 27439, 545 mm TL, R/V Africana cruise
054, West Coast Demersal Survey, bottom trawl, station A5867 054 E01, 35° 44.4´ S, 19° 12.2´ E, 763 m, 20 June
1987.
Apristurus pinguis (1 specimen): H3101-03 male adult, southwest of Cape Leeuwin, Western Australia, 35°
00´ S, 114° 29´ E, 1100-1120 m, 27 May 1992.
Apristurus riveri (1 specimen): USNM 201760, adult female, 09° 20´ N, 81° 24´ W, 860–915 m, 25 May 1962.
Apristurus spongiceps (1 specimen): Holotype: USNM 51590, adult female, 514 mm TL, 572–1462 m, off
Bird Island near Laysan Atoll in the NW Hawaiian Islands, 5 August 1902.
Acknowledgements
The following individuals are sincerely thanked for their assistance and support: Dave Catania and Jon Fong
(California Academy Sciences), Angus Paterson, Paul Cowley, Roger Bills, Nkosinathi Mazungula, Mzwandile
Dwani, Vuyani Hanisi, and the sh collection staff (SAIAB), Ben Frable (Scripps Institution of Oceanography),
Ralf Thiel, Victoria Sarrazin, Irina Eidus, Björn Kullmann (Center of Natural History Universität Hamburg-
Zoologisches Museum, Department of Ichthyology), Zouhaira Gabsi and Jonathan Piger (Muséum national
d’Histoire naturelle Ichthyology collection), Gavin Naylor (University of Florida, Shark Research Program),
Will White (CSIRO), Rachel Aitchison, Amber Reichert, Stephanie Schneider, Vivian Ton, Felicia Miller, and
Paul Clerkin (Pacic Shark Research Center, Moss Landing Marine Laboratories) for facilities, logistical, photo-
and radiography support. We are grateful to Ross Shotton, Southern Indian Ocean Deepsea Fishers Association,
Sealord Corporation of New Zealand, the captains, ofcers, and crew of the F/V Will Watch, Daroomalingum
Mauree, Director of Fisheries (retired), Republic of Mauritius, and Boodhun Ramcharrun, Scientic Ofcer,
Mauritius Ministry of Fisheries for their kind facilitation of our work at the Albion Fisheries Research Centre. The
manuscript was reviewed by two anonymous reviewers. Funding support for the Pacic Shark Research Center’s
Lost Sharks project was graciously provided by Andy Sabin, a National Science Foundation grant (DEB 1132229)
to G. Naylor, the Discovery Channel, Save Our Seas Foundation, and the Food and Agriculture Organization
(United Nations).
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