New records and five new species of sipunculans (Sipuncula) from the central and northwestern Mexican Pacific Author Gómez-Vásquez, Julio D. text European Journal of Taxonomy 2024 2024-03-13 925 179 219 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2463/10949 journal article 10.5852/ejt.2024.925.2463 2118-9773 10821775 699EAE25-96FC-4CD0-82D0-78F0C6E1B017 Phascolosoma ( Phascolosoma ) azteca sp. nov. urn:lsid:zoobank.org:act: EB807E85-7A40-48D0-9B1B-57D77D1633F5 Fig. 13 Phascolosoma dentigerum (not Selenka & de Man, 1883 ) – Steinbeck & Ricketts 1941: 345–346 . — Fisher 1952: 432–434 , pl. 39 figs 4–7 (based on material collected by Ricketts). Etymology This species is named after the ancient Mexican culture of the great Tenochtitlan commonly known as the Aztecs. The epithet in a noun in apposition ( ICZN 1999 , Art. 31.1). Material examined Holotype MEXICO • Jalisco , Los Arcos Beach ; 22 Jan. 2001 ; depth 2 m ; LIB leg.; in dead coral ; EMU-13443 . Paratypes MEXICO • 19 specs ; same collection data as for holotype; EMU-13444 • 10 specs ; same collection data as for holotype; UMAR-SIPU 139 • 7 specs ; Sayulita Beach ; 21°01ʹ39ʺ N , 105°16ʹ59ʺ W ; 19 Feb. 2000 ; depth 3 m ; EMU-13438 • 8 specs ; Punta Raza Beach ; 21°01ʹ59ʺ N , 105°18ʹ51ʺ W ; 11 Apr. 1996 ; EMU-13439 . Other material MEXICO – Baja California • 1 spec. ; Los Ángeles Bay ; 28°56ʹ55.48ʺ N , 113°33ʹ26.36ʺ W ; 25 May 1986 ; SSV and JLG leg.; ECOSUR-S0272 . – Baja California Sur • 6 specs ; La Paz , Tecolote Beach ; 24°20ʹ13.38ʺ N , 110°19ʹ04.7ʺ W ; 15 Oct. 1986 ; SSV and NEG leg.; intertidal; ECOSUR-S0271 • 1 spec. ; La Paz , Presidente Beach ; 19 Apr. 1987 ; RBZ leg.; in dead coral ; UMAR-SIPU 140 • 3 specs ; La Paz , El Caimancito Beach ; 24°12ʹ10.43ʺ N , 110°18ʹ01.09ʺ W ; 10 Oct. 1987 ; depth 2 m ; SSV leg.; in rocks ; ECOSUR-S0275 • 1 spec. ; Cabo Pulmo ; 1989; in dead coral ; UMAR-SIPU 149 • 1 spec. ; El Tesoro Beach ; 17 Jul. 1996 ; UMAR-SIPU 142 • 1 spec. ; La Paz , Calerita Beach ; 18 Jul. 1996 ; intertidal; EMU-13442 • 1 spec. ; La Paz , El Caimancito Beach ; 24°12ʹ15.00ʺ N , 110°18ʹ02.96ʺ W ; 29 Feb. 2004 ; depth 1 m ; PSS and MTH leg.; inhabiting Porites sp. ; ECOSUR-S0268 • 10 specs ; La Paz , Balandra Beach ; 24°19ʹ16.20ʺ N , 110°19ʹ33.54ʺ W ; 2 Mar. 2004 ; depth 1 m ; PSS and MTH leg.; on oyster ; ECOSUR-S0273 . – Sinaloa • 35 specs ; Mazatlán , Pinitos Beach ; 23°12ʹ31.93ʺ N , 106°25ʹ39.77ʺ W ; 22 Feb. 2004 ; depth 2 m ; PSS and MTH leg.; on oyster ; ECOSUR-S0265 • 3 specs ; Mazatlán , Pinitos Beach ; 23°12ʹ28.02ʺ N , 106°25ʹ32.69ʺ W ; 23 Feb. 2004 ; depth 1 m ; PSS and MTH leg.; associated with sabellariids ; ECOSUR-S0274 • 3 specs ; Mazatlán , Cerritos Beach ; 23°17ʹ49.63ʺ N , 106°29ʹ08.51ʺ W ; 27 Feb. 2004 ; PSS and MTH leg.; on oyster with green and red algae ; ECOSUR-S0276 . – Nayarit • 5 specs ; Cabo Litibu ; 20°47ʹ21ʺ N , 105°31ʹ03ʺ W ; 9 Apr. 1996 ; depth 3 m ; UMAR-SIPU 143 • 18 specs ; Sayulita Beach ; 20°47ʹ24ʺ N , 105°31ʹ54ʺ W ; 10 Apr. 1996 ; depth 3 m ; UMAR-SIPU 144 • 4 specs ; Guayabitos Beach ; 21°02ʹ06ʺ N , 105°19ʹ14ʺ W ; 11 Apr. 1996 ; depth 3 m ; UMAR-SIPU 145 • 8 specs ; Punta Raza Beach ; 21°01ʹ59ʺ N , 105°18ʹ51ʺ W ; 19 Feb. 2000 ; UMAR-SIPU 146 • 1 spec. ; Guayabitos Beach , naval base; 22°08ʹ00ʺ N , 105°31ʹ00ʺ W ; 19 Feb. 2000 ; EMU-13441 • 3 specs ; Chacala Beach ; 21°09ʹ55ʺ N , 105°13ʹ39ʺ W ; 20 Feb. 2002 ; EMU-13440 • 2 specs ; Sayulita Beach ; 20°52ʹ15ʺ N , 105°26ʹ40.4ʺ W ; 28 Nov. 2004 ; depth 1 m ; PSS et al . leg.; under rocks ; ECOSUR-0267 • 8 specs ; Banderas Bay , Manzanilla Beach ; 20°44ʹ25.49ʺ N , 105°23ʹ24.33ʺ W ; 29 Nov. 2004 ; depth 2 m ; PSS et al . leg.; in rocks ; ECOSUR-0277 . – Jalisco • 21 specs ; Los Arcos Beach ; 20°32ʹ30ʺ N , 105°18ʹ24ʺ W ; 12 Apr. 1996 ; UMAR-SIPU 147 • 4 specs ; San Patricio Melaque Beach ; 19°13ʹ12.08ʺ N , 104°42ʹ49.95ʺ W ; 2 Dec. 2004 ; depth 3 m ; PSS et al . leg.; in rocks ; ECOSUR-0266 • 2 specs ; Barra de Navidad , Corrales Beach ; 19°11ʹ14.08ʺ N , 104°41ʹ42.84ʺ W ; 3 Dec. 2004 ; depth 4 m ; PSS et al. leg.; in rock ; ECOSUR-0269 . – Colima • 3 specs ; La Audiencia Beach ; 19°06ʹ11ʺ N , 104°21ʹ01ʺ W ; 15 May 2006 ; EMU-13445 • 2 specs ; La Audiencia Beach ; 19°06ʹ11ʺ N , 104°21ʹ01ʺ W ; 15 May 2006 ; UMAR-SIPU 148 . – Michoacán • 3 specs ; Bucerías Beach ; 19 Dec. 1994 ; SGM and RBZ leg.; UMAR-SIPU 149 . Comparative material ( Phascolosoma ( Phascolosoma ) perlucens Baird, 1868 ) MEXICO – Quintana Roo • 3 specs ; Playa del Carmen , Navega docks ; 23 Aug. 2003 ; MTH leg.; ECOSUR-S0044 . PANAMA • 2specs ; Colón , Portobelo ; 4Jun.2002 ; depth 1m ; JC and SSV leg.; in rocks ; ECOSUR-S0056 . VENEZUELA • 2 specs ; Cumana , Turpialito ; 22 Feb. 2002 ; depth 1.5 m ; IL leg.; inhabiting Millepora sp. ; ECOSUR-S0057 . Description (EMU-13443) Trunk 8 mm in length, pale brown body wall with scattered conical papillae ( Fig. 13A ), larger and denser towards anterior and posterior ends; with pre-anal area of pigmented small, conical papillae ( Fig. 13B ). Introvert twice as long as trunk; 12 small digitiform tentacles, aboral surface with longitudinal dark pigmented band ( Fig. 13C ), arranged in arc surrounding nuchal organ, dorsal to mouth; nuchal organ rounded and bilobed. Hooks curved ( Fig. 13D–E ), 52 µm long, with small secondary tooth, curved streak present, internal triangle separate from streak; hooks arranged in 15 complete rings. Longitudinal dorsal reddish band on posterior 80% of introvert towards anus. Dorsal conical papillae, posteriorly directed, on posterior half of introvert. Longitudinal musculature in 18 anastomosing bands. Four retractor muscles attached at 50% of trunk length, ventral pair attached to six bands of longitudinal musculature ( LMB 2–7), dorsal pair attached to two bands ( LMB 6–7), anterior to ventral pair. Paired nephridia approximately 50% of trunk length; Fig. 13. Phascolosoma ( Phascolosoma ) azteca sp. nov. (EMU-13443). A . Lateral overview, introvert contracted. B . Close-up of introvert base and anal area. C . Tentacles. D . Mid-posterior hook; asterisk indicates bubble inside clear streak. E . Illustration of hook. F . Internal anatomy. Abbreviations: see Material and methods. Scale bars: A, F = 2 mm; B–C = 0.5 mm; D–E = 20 µm. Fig. 14. Phascolosoma ( Phascolosoma ) perlucens Baird, 1868 (ECOSUR S0044). A . Lateral overview, introvert contracted. B . Close-up of introvert base and anal area. C . Tentacles; asterisk indicates position of mouth. D . Mid-posterior hook; asterisk indicates bubble inside clear streak. E . Illustration of hook. F . Internal anatomy. Abbreviations: see Material and methods. Scale bars: A, F = 4 mm; B = 2 mm; C = 0.7 mm; D = 20 µm. nephridiopores open anterior to anus. Spindle muscle attaches intestine to rectum anteriorly and to caudal region posteriorly ( Fig. 13F ). Variations Based on 20 paratypes and the extra material examined, the number of hook rings varies according to the size of the specimen, a specimen with a trunk length of 6 mm having 12 hook rings and a specimen with a trunk length of 10 mm having 20 complete rings. The number of tentacles also varies according to the size of the specimen from 10 to 14. The Caribbean specimens ( Fig. 14 ) have a greater trunk length, 13 mm long with 12–16 tentacles. Habitat Intertidal to subtidal ( 12 m ); inhabiting Porites sp. , in rocks, associated with sabellariid tubes, algae and oyster shells. Distribution Mexican Pacific: present along the central and northwestern Mexican Pacific coast, from Baja California to Michoacán . Remarks Specimens of Phascolosoma ( Phascolosoma ) azteca sp. nov. are morphologically close to P. ( P. ) perlucens Baird, 1868 . For comparative purposes some specimens of P . ( P .) perlucens from the Venezuelan coast were examined, and these specimens were consistent with the descriptions and redescriptions of that species ( Baird 1868 ; Rice & Stephen 1970 ). Morphological differences were found between specimens from the Caribbean and those from the central and northwestern Mexican Pacific. Specimens of Phascolosoma ( Phascolosoma ) perlucens are larger and have 12–16 tentacles, whereas P. ( P .) azteca sp. nov. has 10–14. Moreover, P. ( P .) perlucens has more longitudinal muscle bands, 20–22, while P. ( P .) azteca has 17–20. Furthermore, the ventral retractor muscles are attached to six longitudinal muscle bands (LMB 2–7) in P. ( P. ) azteca and to five (LBM 2–6) in P . ( P .) perlucens . Phascolosoma ( Phascolosoma ) perlucens has pre-anal pigmented papillae on 10–20% of the posterior introvert ( Fig. 14B ), while in P. ( P .) azteca sp. nov. they are restricted to 5% of the posterior introvert ( Fig 13B ). Finally, the hooks of P . ( P .) perlucens have a principal tooth that is slightly straight and the secondary tooth is somewhat like a hump ( Fig. 14D–E ), whereas in P. ( P. ) azteca the hooks have a more curved principal tooth and the inner margin is concave, making the secondary tooth look more projected and slightly acute, rather than like a hump ( Fig. 13D–E ). Since the morphology of Phascolosoma ( Phascolosoma ) azteca sp. nov. resembles that of P . ( P .) perlucens , the newly described species belongs to the P . ( P .) perlucens species complex, for which, as mentioned by Kawauchi & Giribet (2010) , there is evidence of multiple genetic clades, and some morphological differences can be shown between the populations as well. However, the morphological differences listed above indicate that P . ( P .) azteca from the northwestern Mexican Pacific is a valid species, distinct from P . ( P .) perlucens from the Caribbean.