New Records of the Bobtail Squid, Euprymna Hyllebergi Nateewathana, 1997 with Designation of a Neotype

Home , Bobtail squid, Euprymna, Euprymna tasmanica, Sepiolidae

Phuket mar. biol. Cent. Res. Bull. 70: 15–27 (2011)

NEW RECORDS OF THE BOBTAIL SQUID, EUPRYMNA HYLLEBERGI NATEEWATHANA, 1997 WITH DESIGNATION OF A NEOTYPE

Charatsee Aungtonya1, Anuwat Nateewathana2, Ole Secher Tendal3 and Jaruwat Nabhitabhata4

1Phuket Marine Biological Center, P.O. Box 60, Phuket 83000, Thailand 2Department of Marine and Coastal Resources, Bangkok, Thailand 3Zoological Museum, SNM, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark 4Centre for Biodiversity of Peninsular Thailand (CBIPT), Faculty of Science, Prince of Songkla University, Hatyai, Songkhla 90112, Thailand Corresponding author: Charatsee Aungtonya Email: [email protected]

ABSTRACT: A total of 265 specimens, 118 males and 147 females, of the bobtail squid, Euprymna hyllebergi, are registered in the Reference Collection, Phuket Marine Biological Center, Thailand. Nearly all specimens were collected from Thai waters, the Andaman Sea and the Gulf of Thailand. The species is here reported as a new record for Myanmar waters and the distribution in the Indian Ocean has been extended to the west of the Andaman Islands. A male neotype is designated on a specimen collected from the original locality in order to replace the lost male holotype specimen. The neotype is deposited in the Reference Collection of Phuket Marine Biological Center, Thailand, as is the remaining female paratype, whereas selected specimens are deposited in National Science Museum Tokyo, Japan, U.S. National Museum, Washington D.C., USA and the Zoological Museum, SNM, University of Copenhagen, Denmark. Measurements of the neotype, paratype, and selected specimens are presented and discussed.

Key word: bobtail squid, Euprymna hyllebergi, Thai waters, neotype

INTRODUCTION placed as invalid while four species, E. albatrossae Voss, 1963, E. bursa (Pfeffer, 1884), E. phenax Bobtail squids are small benthic Voss, 1963, and E. stenodactyla (Grant, 1833), cephalopods, belonging to the family Sepiolidae were treated as unresolved species (Norman & Leach, 1817, which contains about 14 genera and Lu, 1997). E. albatrossae, E. bursa, and E. phenax over 50 species. Sepiolid squids are distributed were known only from the types. The original type worldwide, ranging from tropical to temperate and material of E. stenodactyla is lost, no further sub-polar waters of all oceans (Nateewathana, material has been found in Mauritius yet and the 1997a). description of the species is poor (Norman & Lu, According to the most recent revision by 1997). Furthermore, a nominal species, E. similis Norman & Lu (1997) and a later paper on the genus Sasaki, 1913, was considered a junior synonym by Nateewathana (1997b), 13 species have been of E. morsei (Norman & Lu, 1997). referred to Euprymna Steenstrup, 1887. Six The species E. morsei, E. stenodactyla, species, E. berryi Sasaki, 1929, E. hoylei Adam, E. berryi and E. hyllebergi, have been reported 1986, E. hyllebergi Nateewathana, 1997, E. morsei from Thai waters, the Andaman Sea and the Gulf (Verrill, 1881), E. scolopes Berry, 1913, and E. of Thailand, by Chotiyaputta et al. (1992), tasmanica (Peffer, 1884) are currently accepted Chotiyaputta (1993), Supongpan (1995), in the genus. Two species, E. pusilla (Peffer, Nateewathana (1997b) and Nateewathana et al. 1884) and E. schneehageni (Peffer, 1884), were (2001). 16 Phuket mar. biol. Cent. Res. Bull.

According to Nateewathana et al. (2001) the male neotype of Euprymna hyllebergi in order the occurrence of E. morsei, E. stenodactyla, and to replace the lost male holotype and paratypes E. berryi in Thai waters was still uncertain since previously listed in Aungtonya et al. (2006, 2007), the voucher material could not be located. and describes specimens deposited in other However, E. morsei and E. stenodactyla from the museums. This study aims to facilitate future Andaman Sea and Myanmar waters have been revision and taxonomic work on this genus and to registered at the PMBC Reference Collection in update the known distribution of the species. 2007. Future taxonomic study on those specimens is pending. MATERIALS AND METHODS All specimens of Euprymna hyllebergi deposited in the Reference Collection of Phuket The bobtail squids were obtained from Marine Biological Center, were checked and fishing boats, research vessels, fish markets, and measured, but none were in accordance with the fish landings along the Andaman Sea coast of holotype. The first and the fourth authors Thailand and the Gulf of Thailand as described by contacted the cephalopod taxonomists who had Nateewathana (1997b) and Nateewathana et al. previously studied the type material, but they all (2001). Additional material for the present study denied any knowledge about the fate of those types. was primarily obtained from the R.V. Chulaphorn We conclude that the holotype is lost. of the Deep Sea Fishery Technology Research and Euprymna hyllebergi is close to E. hoylei, Development Institute operating off the Andaman but differs in the arrangement of suckers on the Sea coast of Thailand, and from fishing boats, fish hectocotylized arm, the size and distribution of markets and fish landings along the Andaman Sea enlarged suckers on arms II–IV, and in the length coast of Thailand and the Gulf of Thailand. of the tentacles (Nateewathana, 1997b: Fig. 3). Taxonomic studies are based on Nateewathana E. hoylei is known from the tropical (1997b). Western Pacific to North-West Australia (Norman The specimen designated as the neotype & Lu, 1997). It is characterized by lacking enlarged and five lots of specimens were selected from the suckers on arm II in mature males, having 3–4 samples in the Reference Collection of Phuket enlarged suckers in dorsal and ventral rows of arm Marine Biological Center. The neotype was, like pair IV and ventral row only of arm pair III the holotype, collected from small scale fishing (Norman & Lu, 1997, Nesis, 1987). The suckers areas in Trang Province, at a depth of less than 40 on arm II–IV of E. hyllebergi do not have any m off the Andaman Sea Coast of Thailand. significantly or abruptly enlarged suckers Measurements follow those of (Nateewathana, 1997b). E. hyllebergi has a high Nateewathana (1997b). Definitions of number of stout papillae with a slitlike aperture in measurements and indices are summarized in Table the distal half of the hectocotylus. The papillae of 1 and in Figure 1. The difference of the means of E. hyllebergi are crowded in rows of 4–6 suckers all the measurements and indices is compared with in the middle part, and reduced to two rows at the those listed by Nateewathana (1997b). Differences tip of the hectocotylus. were considered significant when The male characters are the most important features distinguishing the two species, E. hoylei and E. hyllebergi. Furthermore, the Specimens of the species, the newly arrangement of the sessile suckers of the male is designated neotype, and selected materials are the only diagnostic feature to characterize the deposited in the Reference Collection of Phuket species of the genus, as well as other genera in Marine Biological Center, Thailand (PMBC), the Family Sepiolidae. Hence it is necessary to National Science Museum Tokyo, Japan (NSMT), select a male neotype of E. hyllebergi. U.S. National Museum, Washington, D.C., USA The present report lists all specimens of (USNM), and the Zoological Museum, SNM, this species in the Reference Collection, designates University of Copenhagen, Denmark (ZMUC). 17 New records of the bobtail squid

Table 1. Definition of counts, measurements and indices (modified after Nateewathana, 1997b).

ML Mantle Length dorsal mantle length measured from the anterior-most point of mantle to posterior tip, along dorsal mid-line. MWI Mantle Width Index greatest straight-line (dorsal) width of mantle as a percentage of mantle length. FLI Fin Length Index greatest length of fins as a percentage of mantle length. FWI Fin Width Index greatest width (dorsally) across both fins as a percentage of mantle length. FBI Fin Base Index length of fin base as a percentage of mantle length. HLI Head Length Index dorsal length of head measured from point of fusion of dorsal arms to anterior tip of nuchal locking cartilage as a percentage of mantle length. HWI Head Width Index width of head across midpoint of eyes as a percentage of mantle length. ALI Arm Length Index length of arm measured from first basal (proximal-most) sucker to tip of arm as a percentage of mantle length. ASI Arm Sucker Index diameter of largest normal arm sucker on each designated arm as a percentage of mantle length. TtLI Tentacle Length Index total length of tentacular stalk and club as a percentage of mantle length. ClLI Club Length Index length of club as a percentage of mantle length. HcLI Hectocotylized Length Index length of modified portion of arm measured from proximal-most modified sucker to tip of arm as a percentage of total length of hectocotylized arm (left arm I). EDI Eye Diameter Index diameter of eye across bulbus as a percentage of mantle length. LnDI Lens Diameter Index diameter of eyelens as a percentage of mantle length.

RESULTS and ZMUC CEP-25 have been selected from PMBC 11742, PMBC 11748 and PMBC 11747, A total of 265 specimens, 118 males and respectively. Two females of PMBC 11734 have 147 females, were registered in the Reference been selected and registered as NSMT-Mo 76425 Collection (see Table 2). Nearly all of the specimens and ZMUC CEP-51. The male neotype, PMBC were collection from Thai waters, the Andaman accession number 21339, is deposited in the Sea and the Gulf of Thailand, except for PMBC Reference Collection of Phuket Marine Biological 11781 and PMBC 11775 which were collected Center, as is the remaining female paratype, PMBC from the Indian Ocean, west of the Andaman 11731. Islands and Myanmar waters, respectively. The Selected measurements and indices of the latter specimens are the first records of E. type materials and selected specimens of E. hyllebergi from the Indian Ocean, west of the hyllebergi are presented in Table 3. Mean of indices Andaman Islands and Myanmar waters, (in percent), standard deviation of five males and respectively. four females are presented in Table 4. The t-test The neotype was selected from PMBC comparing the means of all the measurements and 11742 and registered as PMBC 21339 (Fig. 2). indices of the present material and those given by Three lots of NSMT-Mo 76424, USNM 1150474, Nateewathana (1997b) are presented in Table 5. 18 Phuket mar. biol. Cent. Res. Bull.

Figure 1. Diagrammatic illustration of measurements in sepiolids (modified after Nateewathana, 1997b). AL = arm length, C1L = club length, ED = eye diameter, FB = fin base, FL = fin length, FW = fin width, HL = head length, HW = head width, LD = lens diameter, ML = mantle length, MW = mantle width, TtL = tentacle length.

Euprymna hyllebergi Nateewathana, 1997 Phangnga Bay, push net, 18 June 1988; USNM (Figs. 2A–B, 3A–B, 4A–C, Table 2–5) 1150474, 1 male and 1 female, Phuket fish market, Phuket Province, 23 Aug 1995; ZMUC CEP-25, 2 Euprymna hyllebergi – Nateewathana, 1997b: 466– males, Krabi fish market, Krabi province, 17 Dec 474, figs. 2–5, Table 2. 1994; ZMUC CEP-51, 1 female, Chong Pra, Phangnga Bay, push net, 18 June 1988. Neotype. PMBC 21339, 1 male, Kantang fish landing, Trang province, 14 Feb 1996 (Figs. 2– Material examined. 265 specimens have been 3). examined and registered (see Table 2). Paratype. PMBC 11731, 1 female, Tha Lane, Phangnga Bay, push net, 23 July 1989 Description. Colour in alcohol yellowish; numerous large and conspicuous purplish brown Selected specimens. NSMT-Mo 76424, 1 male, chromatophores cover mantle, head and arms, Kantang fish landing, Trang Province, 14 Feb more dense in middle part of dorsal and ventral 1996; NSMT-Mo 76425, 1 female, Chong Pra, sides. Mantle dome-shaped, thick, broad 19 New records of the bobtail squid

anteriorly and rounded posteriorly, slightly longer with smooth horny ring, rounded aperture on than wide (Figs. 2–3, 4A–B); antero-dorsal margin normal sucker, but more ovate on enlarged one. fused with head (Figs. 2, 4A). Large portion of Left arm I of male hectocotylized, stout, shorter the tubular funnel visible, median ventral margin than other arms and curved outwards slightly concave (Figs. 2B, 4B–C). Fins rounded, (Nateewathana, 1997b: figs. 3a, 4a–b). The size almost circular in outline, separate and attached at of arm suckers on different arms varied. Tentacles middle of mantle; anterior margin to posterior round, flattened on oral surface, edges of flat area margin nearly straight. Head broad, dorsoventrally angled, dorsal margin elevated into a low keel flattened and compact, width slightly less than towards club. Club short, curled, and rounded with mantle width; eyes large, oval with almost circular numerous rows of very small suckers. Gladius pupil. Funnel long, tubular, free for most of its absent. Buccal membrane smooth without suckers. length, reaching to gap between ventral arms (Fig. 4B–C). Funnel valve triangular to rounded flaplike. Type locality. Small scale fishing areas in Trang Funnel organs with a roughly triangular dorsal pad Province, in the depth less than 40 m, theAndaman and two oval ventral pads. Anterior end of dorsal Sea coast of Thailand. pad with a low crest projected in midline. Funnel locking cartilage ovate, rounded at both ends with Distribution. Indian Ocean (Andaman Sea and deep groove (Fig. 4C); mantle cartilage straight, Myanmar waters with range extension to the west ridge-like, two times longer than funnel cartilage. of the Andaman Islands) and Gulf of Thailand. Arms long, subequal, rounded in cross section, tapering distally. Web C (between arms II and III) Remarks. The characters of all specimens match developed and D distinct (between arms III and well with those of E. hyllebergi, as described and IV). Web D extends up about one-fourth of arm figured by Nateewathana (1997b). Description of length. Suckers almost equal-sized, subglobular, beak, radula, ink sac, and spermatophores of the with a small, smooth aperture; pedicel thin. In species are not repeated herein. females, arm suckers quadriserial but biserial at The right tentacle in NSMT-Mo 76424 and base and distally. In male, arm suckers globular the left tentacle in ZMUC CEP-51 are missing.

A B

Figure 2: Euprymna hyllebergi Nateewathana, 1997 (PMBC 21339). Neotype, male: (A) dorsal and (B) ventral. 20 Phuket mar. biol. Cent. Res. Bull.

A B

Figure 3: Euprymna hyllebergi Nateewathana, 1997 (PMBC 11731). Paratype, female: (A) dorsal and (B) ventral.

A B

Figure 4. Euprymna hyllebergi Nateewathana, 1997 (PMBC 21339). Neotype, male: (A) dorsal view; (B) ventral view; (C) funnel and funnel locking-cartilages. Scales = 2 cm (A–B) and 0.5 cm (C). 21 New records of the bobtail squid R e ma r ks o r i g n a l re c d e as E up r ym na s te noda c tyla ( G r a n t , 1 8 3 ) b y C . F E. R o p e r i n 1 9 79 I d en t if i er A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na P huk et Kra bi T r a ng T r a ng Ra n ong P h a ngnga T r a ng Kra bi P h a ngnga P h a ngnga P h a ngnga T r a ng A nd a m n Sea Kra bi P h a ngnga P h a ngnga T r a ng Kra bi Kra bi Ra n ong Kra bi P huk et P huk et P h a ngnga P h a ngnga P huk et Kra bi S a t ul P h a ngnga Ra n ong A nd a m n Sea P h a ngnga P huk et Kra bi P r ov i n ce L o c a l i ty – K r a b i f s h m rket K a n ta g fi sh l nd i ng K a n ta g fi sh l nd i ng Ka pur T h a L n e , P g B ay R o k I s l a nd K r a b i f s h m rket Chong Pra, P h a ng n g Bay Ra y a Ri n g I s l nd T h a L n e , P g B ay K a n ta g fi sh l nd i ng 8 ° 0 2 ´ N , 9 3 É S o u t h w e s f L a n I l nd T a e ng C p e, P h n g Bay P h a ng n g Bay K a n ta g fi sh l nd i ng K r a b i f s h m rket K r a b i f s h m rket – K r a b i f s h m rket P h u k e t fi s m a r et T u k a e C pe R a y i n g I s l d , P h B ay M a k I s l n d , P h g B ay P h u k e t fi s m a r et S o u t h w e s f L a n I l nd T a m l ng f i s h nd – J a m I s l nd 7 ° 4 8 ´ N , 9 3 0 É Na k ae I s l a nd S a p u m B ay D a m H o k I s l nd re ma ining i n the Re f ere ce C oll ectio o Ph u k et M ar e Bi ol gi cal nt r. 2 1 4 6 1 1 3 2 1 3 5 7 6 17 6 1 1 1 7 1 1 1 2 7 3 1 1 1 1 F e m a le 3 2 5 3 1 1 2 3 6 4 5 1 2 3 6 1 1 2 Ma le Eupr y m na h yllebe r gi 5 1 6 11 1 1 6 3 2 3 5 9 9 3 2 15 12 1 1 5 12 2 1 1 4 3 13 4 1 1 1 3 1 N o . of s p e c. T y pe H O L T Y P E s p e c i m n l o st P AR A TYPE P A R T Y E s p e c i m n l o st P A R T Y E s p e c i m n l o st Det a ils o f s p eci m e n 1 6 07 1 727 1 728 1 729 1 730 1 731 1 732 1 733 1 734 1 735 1 736 1 737 1 738 1 739 1 740 1 741 1 742 1 744 1 745 1 746 1 747 1 748 1 749 1 750 1 751 1 752 1 753 1 755 1 756 1 757 1 758 1 759 1 760 1 761 P MB C N o. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 T ab l e 2. N o. 22 Phuket mar. biol. Cent. Res. Bull. R e ma r ks s p e c i m n w a l t ed f ro m P M B C 1 7 42 s p e c i m n f o u d t he b o t l e f P M BC 1 7 3 , b u t n ot i d e n ti c a l t o ri g al p a rat y pe s p e c i m n f o u d t he b o t l e f P M BC 1 7 3 9 , b u t n ot i d e n ti c a l t o ri g al p ara t yp e spe c i m ns I d en t if i er A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na A . N a t e w h na T . K u b o d e ra T . K u b o d e ra A . N a t e w h na A . N a t e w h na A . N a t e w h na T r a ng P h a ngnga Kra bi – Kra bi A nd a m n Sea A nd a m n Sea P huk et Kra bi Ra n ong T r a ng M y a n m r wa t ers P a t ni T r a ng S a m u t P r k an In d ia n Oc e an A nd a m n Sea T r a ng T r a ng A nd a m n Sea A nd a m n Sea A nd a m n Sea T r a ng – – P r ov i n ce L o c a l i ty T r a n g f i s h m rket o f Y a i I s l nd E a s t o f L n I l nd – – 6 ° 5 8 ´ N , 9 4 É 6 ° 5 7 ´ N , 9 8 4 É Ra n g Y a i Is l nd – – K a n ta g fi sh l nd i ng 1 3 ° 2 7 ´ N , 9 0 É P a t n i f s h l d ng K a n ta g fi sh l nd i ng Sa m u t Pra k a n f is h la nd i ng 7 ° 1 ´ N , 9 0 É 7 ° 0 4 ´ N , 9 8 5 3 É K a n ta g fi sh l nd i ng K a n ta g fi sh l nd i ng 9 ° 3 4 ´ N , 7 É 7 ° 5 1 ´ N , 9 8 3 É 9 ° 0 ´ N , 7 5 4 É K a n ta g fi sh l nd i ng – – 1 2 1 1 1 2 1 1 1 1 1 13 1 1 1 1 6 9 4 1 1 2 F e m a le 1 1 2 5 2 10 17 1 6 1 3 3 Ma le 1 2 2 1 1 1 2 1 3 1 1 1 18 1 1 1 3 16 26 1 10 1 1 4 5 N o . of s p e c. T y pe NEOTYPE t h e n u m b r o f s p c i P M B C a g d , l A x 1 N w (1 9 7 b), me (c on t inued) 1 762 1 763 1 764 1 765 1 766 1 767 1 768 1 770 1 772 1 773 1 774 1 775 1 776 1 777 1 780 1 781 1 782 1 785 1 787 1 4 420 1 9 903 1 9 904 2 1 339 2 3 937 2 5 004 P MB C N o. 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 T ab l e 2. N o. R e m a r k s : P M B C a c e s i o n u m b r w t l d h p x. 23 New records of the bobtail squid 51 39.94 57.74 28.42 169. 11 f r o m the A nd a ma n S ea,

28.65 81.85 76.18 48.94 57.74 134 . 90 1 3 5.50 37.63 34.24 58.71 57.35 64.96 99.34 84.87 3.66 2.43 5.34 3.20 4.54 2.81 41.64 60.94 0.00 26.35 25.97 14.52 13.62 124.15 102.39 25 Ma l e Female Z M U C EP 2 7 . 21 8 3 . 83 5 2 . 11 5 3 . 55 6 8 . 83 8 . 06 98.46 101.22 88.53 2.94 4.01 2.53 2.94 4.41 4.59 4 2 . 08 5 8 . 01 3 0 . 10 1 5 . 40 1 10.66 Eupr y m na h yllebe r gi S e lec t ed sp cim ns F e m a le 2 6 . 79 8 . 28 6 4 . 05 6 7 . 19 9 1 . 75 99.22 93.77 101.14 108.34 91.87 9 6 . 90 2.24 2.61 2.43 2.43 6 2 . 64 2 4 . 15 1 5 . 57 U S NM 1 5 0 4 74 1 1 1 M a le 2 9 . 02 9 0 . 45 54.51 50.09 35.70 39.94 32.97 5 3 . 62 6 4 . 13 9 1 . 94 3.96 3.79 5.34 5.00 6 2 . 93 2 7 . 08 1 3 . 20 290.18 246.62 285.34 229.6 0 124.91 105.10 1 1 N S M T - Mo 7 6 425 F e m a le 35.22 7 4 . 82 5 1 . 02 3 . 19 5 0 . 03 5 9 . 71 5 9 . 00 74.76 69.96 104.31 67.18 2.13 2.30 2.98 2.73 84.44 31.63 31.74 2 4 . 11 1 2 . 12 1 2 = l e f t ten acle du to the ri ght o ne lost. Th v a u es in b old tex are ou th r ng N S M T - Mo 7 6 424 M a le 33.63 7 . 19 4 8 . 41 2 8 . 49 5 2 . 81 6 1 . 11 9 7 . 71 4.16 4.46 4.46 4 6 . 65 5 9 . 99 1 9 . 80 1 3 . 56 98.33 2 234.67 1 P a rat y pe P M BC 1 7 31 F e m a le 2 . 27 9 1 . 02 5 8 . 96 4 6 . 74 4 6 . 43 7 3 . 15 6 9 . 33 86.30 114.93 77.19 73.37 110.70 2.92 2.97 3.37 2.92 2.25 2 5 . 82 1 5 . 67 34.98 1 19.98 1 P M BC 2 1 339 M a le 3 0 . 98 8 4 . 83 4 . 09 5 4 . 71 6 3 . 52 3.23 4.03 5.23 6.17 42.32 6 5 . 73 2 . 60 1 2 . 33 Ne o ty pe 26.44 327.73 129.50 152.09 119.92 1 3 5.15 146.7 6 159.69 132.82 106.75 143.54 120.27 116.17 = t ip o f he ri ght ar m bro ke n; 1 M ea s u re m e nt ( mm ) an d indice % o f n otyp , p arat y pe a nd lected eci I I I I I I I I I II I II IV IV III II I R e gis t rat i on N o. I n d e x\ Sex ML ( m m) M WI FLI FWI FBI HLI H WI AL AL AL AL AS AS AS AS TtLI CI LI H c LI E DI Ln DI T ab l e 3. Th a ila n d. Rem a r k s: m easure e nt s a nd ind i ces re p o rte d by Nateewa t h n ( 1 9 97b ). 24 Phuket mar. biol. Cent. Res. Bull.

Table 4. Mean (X) of indices (%) and standard deviation of type materials and selected specimens of Euprymna hyllebergi from the Andaman Sea, Thailand. Male Female Index n Mean SD Range n Mean SD Range

ML (mm) 5 29.90 2.48 27.21–33.63 4 28.18 5.37 22.27–35.22 MWI 5 83.63 4.81 77.19–90.45 4 82.57 8.27 74.82–91.02 FLI 5 49.61 3.96 44.09–54.51 4 54.45 4.54 50.09–58.96 FWI 5 132.78 9.70 119.92–146.76 4 145.61 12.27 135.15–159.69 FBI 5 32.24 4.72 26.44–37.63 4 38.53 6.23 33.19–46.74 HLI 5 54.68 2.35 52.81–58.71 4 54.47 7.84 46.43–64.05 HWI 5 64.51 2.81 61.11–68.83 4 64.45 7.09 57.74–73.15

ALII 5 96.76 7.18 88.06–106.75 4 76.24 14.83 59.00–91.75

ALIII 5 123.64 12.67 110.66–143.54 4 90.67 12.68 74.76–102.39

ALIIII 5 106.48 8.56 98.33–120.27 4 83.20 11.52 69.96–93.77

ALIVI 5 106.33 7.17 98.46–116.17 4 81.50 13.64 67.18–96.90

ASII 5 3.42 0.53 2.94–4.01 4 2.46 0.35 2.13–2.92

ASIII 5 3.72 0.48 2.94–4.16 4 2.68 0.48 2.30–3.37

ASIIII 5 4.96 0.48 4.41–5.34 4 2.88 0.33 2.43–3.20

ASIVI 5 4.95 0.71 4.46–6.17 4 2.55 0.26 2.25–2.81 TtLI 5 273.50 41.21 229.60–327.73 4 155.04 70.23 84.44–246.62 CILI 5 40.89 5.50 31.74–46.65 4 42.30 13.98 31.63–62.64 HcLI 5 61.52 2.95 58.01–65.73 4 EDI 5 25.19 4.02 19.98–30.10 4 25.01 1.02 24.11–25.97 LnDI 5 13.80 1.19 12.33–15.40 4 14.24 1.70 12.12–15.67

Table 5. t-test of the mean of all measurements and indices by Nateewathana (1997b) and this study. Male Nateewathana (1997b) present study

Index n Mean SD n Mean SD T-test

ML (mm) 20 27.20 4.20 5 29.90 2.48 No diff MWI 20 81.20 11.30 5 83.63 4.81 No diff FLI 20 49.10 7.10 5 49.61 3.96 No diff FWI 20 131.10 13.80 5 132.78 9.70 No diff FBI 20 31.50 4.00 5 32.24 4.72 No diff HLI 20 52.80 8.50 5 54.68 2.35 No diff HWI 20 65.20 7.10 5 64.51 2.81 No diff

ALII 20 103.70 20.00 5 96.76 7.18 No diff

ALIII 20 141.00 15.70 5 123.64 12.67 Sig diff

ALIIII 20 118.20 14.10 5 106.48 8.56 No diff

ALIVI 20 118.60 18.00 5 106.33 7.17 No diff

ASII 20 3.50 0.50 5 3.42 0.53 No diff

ASIII 20 4.40 0.60 5 3.72 0.48 Sig diff

ASIIII 20 5.10 0.70 5 4.96 0.48 No diff

ASIVI 20 5.30 0.60 5 4.95 0.71 No diff TtLI 20 282.80 47.10 5 273.50 41.21 No diff CILI 20 48.40 7.10 5 40.89 5.50 Sig diff HcLI 20 63.40 8.30 5 61.52 2.95 No diff EDI 20 23.30 5.60 5 25.19 4.02 No diff LnDI 20 14.40 2.80 5 13.80 1.19 No diff 25 New records of the bobtail squid

Table 5. (continued)

Female Nateewathana (1997b) present study

Index n Mean SD n Mean SD T-test

ML (mm) 20 24.90 5.50 4 28.18 5.37 No diff MWI 20 80.70 8.90 4 82.57 8.27 No diff FLI 20 52.50 7.80 4 54.45 4.54 No diff FWI 20 142.40 12.80 4 145.61 12.27 No diff FBI 20 35.80 5.00 4 38.53 6.23 No diff HLI 20 55.30 6.20 4 54.47 7.84 No diff HWI 20 67.70 7.90 4 64.45 7.09 No diff

ALII 20 85.40 11.40 4 76.24 14.83 No diff

ALIII 20 110.60 12.30 4 90.67 12.68 Sig diff

ALIIII 20 93.20 8.80 4 83.20 11.52 No diff

ALIVI 20 89.70 9.20 4 81.50 13.64 No diff

ASII 20 2.70 0.40 4 2.46 0.35 No diff

ASIII 20 2.80 0.50 4 2.68 0.48 No diff

ASIIII 20 3.00 0.40 4 2.88 0.33 No diff

ASIVI 20 2.80 0.40 4 2.55 0.26 No diff TtLI 19 266.60 60.70 4 155.04 70.23 Sig diff CILI 19 53.30 10.90 4 42.30 13.98 No diff EDI 20 23.50 3.80 4 25.01 1.02 No diff LnDI 20 14.90 2.10 4 14.24 1.70 No diff

DISCUSSION the t-test of the mean of all measurements and indices by Nateewathana (1997b) and in this study

The Euprymna hyllebergi arm length were considered significant for ALII in both male formula is II > III > IV > I, but occasionally II > and female, for ASIII and ClLI in male only, and III = IV > I (Nateewathana, 1997b). The arm length for TtLI in female (Table 5). formulas of the present material of males and These differences may occur because the females (Table 4, II > III > IV > I), matches those suckers on arms easily fall off and are lost in of Nateewathana (1997b) as well as those in the preserved material and the tip of the first right arm neotype and paratype (Table 3). Differences are, in male specimen was broken. Therefore some however, found in some of the selected specimens; errors occurred in estimation of the length of the four specimens show II > III > IV > I but three first right arm, which was measured from the first other specimens show II > IV > III > I (Table 3). basal (proxima-most) sucker to tip of arm as a These differences occur because the tips of the percentage of mantle length. right arms were broken. Furthermore, according to C.C. Lu (pers. All measurements and indices of the comm., in Nateewathana, 1997b), the length of neotype are in the ranges reported by the tentacles in cephalopods may not be a usable Nateewathana (1997b). Some measurements and taxonomic character since it varies greatly indices in the paratype and selected specimens are, depending on how the specimen is fixed and however, out of these ranges, i.e., Mantle Length preserved. Live fixed animals have short tentacles (ML), Arm Length Index (ALI), Arm Sucker Index because of contraction and, on the other hand, (ASI), Tentacle Length Index (TtLI), and Club specimens thawed from frozen condition have long Length Index (ClLI) (Tables 3–4). Furthermore, tentacles. In order for this character to be of some 26 Phuket mar. biol. Cent. Res. Bull.

use, specimens should be fixed under identical ACKNOWLEDGEMENTS conditions. Specimens from the same batch may vary greatly (C.C. Lu, pers. comm., in We express our appreciation to Dr. Nateewathana, 1977b). Kongkiat Kittiwattanawong, Phuket Marine The mantle length, the first arm length Biological Center (PMBC) for his kind assistance index, the tentacle length index, and club length in t-test Analysis, and Dr. Janek von Byern, index are the main characters/indices used for University of Vienna, Austria, for providing valuable distinguishing the species from other members of comments on the draft of this manuscript. Sincere the genus. Although the tentacle length is thanks are given to Ms. Kanjana Bussabong, the particularly important in recognizing this species, Reference Collection, Phuket Marine Biological it is not necessarily an autopomorphy for the Center, and Ms. Thitima Boonkaew, training species. It is the combination of the arrangement student, PSU, for their kind assistance. Our sincere of suckers on the hectocotylized arm, the size and thanks also go to Mr. Rueangrit Promdam, (former distribution of enlarged suckers on arms II–IV, staff of Reference Collection), and Mr. Patirat and in the length of the tentacles that distinguishes Singdum, the PMBC artist, for photographing and Euprymna hyllebergi. drawings.

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Manuscript received: 17 August 2009 Accepted: 12 June 2011 28 Phuket mar. biol. Cent. Res. Bull.