Prochristianella butlerae Beveridge, 1990

Schaeffner, Bjoern C. & Beveridge, Ian, 2012, Prochristianella Dollfus, 1946 (Trypanorhyncha: Eutetrarhynchidae) from elasmobranchs off Borneo and Australia, including new records and the description of four new species, Zootaxa 3505, pp. 1-25 : 18-20

Prochristianella butlerae Beveridge, 1990

Synonym: Prochristianella macracantha Palm, 2004 (new synonym).

Material examined: Holotype from Dasyatis fluviorum Ogilby off Deception Bay, Queensland, Australia ( SAM V4131); paratypes from D. fluviorum off Caloundra, Queensland, Australia ( SAM AHC 18315/2, 3, 5); 14 voucher specimens from Pa. atrus (labeled as Dasyatis sephen ) off Fog Bay, Northern Territory, and Nickol Bay, Western Australia ( SAM AHC 18314/1–5, 18316/1–9); 6 voucher specimens from Pa. atrus (labeled as Da. sephen ) off Heron Island, Queensland, Australia (QM G217566–217572); 1 specimen from Pastinachus sephen (Forsskål) ( Pa. atrus ?) off Pelabuhan Ratu, Indonesia (holotype of P. macracantha ; ZMB 7361); New material: 2 specimens from Aetomylaeus nichofii (Bloch & Schneider) off Mukah, Sarawak, Malaysia ( SAM AHC 35383; BO-34); 22 specimens from Aetomylaeus vespertilio (Bleeker) off Weipa, Queensland ( SAM AHC 35390; CM03- 61) and off Darwin (Buffalo Creek), Northern Territory, Australia ( SAM AHC 35386–35387; AU-42, AU-43); 31 specimens from N. kuhlii off Pulau Balambangan, Sabah, Malaysia (LRP 7850–7853; SAM AHC 35385 (13x); USNPC 105184 (4x); BO-322) and Lizard Island, Queensland, Australia (QM G233651–52); 1 specimen from Neotrygon cf. ningalooensis (sensu Naylor et al. 2012) off Nhulunbuy (West Woody Island), Northern Territory, Australia ( SAM AHC 35391; NT-8); 8 specimens from Pa. atrus off Weipa, Queensland, Australia ( SAM AHC 35388; CM03-02); 2 specimens from T. lymma 1 (sensu Naylor et al. 2012) off Semporna, Sabah, Malaysia ( SAM AHC 35384; BO-84); 3 specimens from T. lymma 2 (sensu Naylor et al. 2012) off Nhulunbuy (West Woody Island) Northern Territory ( SAM AHC 35392–35393; NT-10, NT-13); 9 specimens from Urogymnus asperrimus 1 (sensu Naylor et al. 2012) off Weipa, Queensland, Australia ( SAM AHC 35389; CM03-53).

Site: Spiral intestine.

Remarks: Prochristianella butlerae was initially described by Beveridge (1990) from the spiral intestines of two species of stingrays of the genus Dasyatis Rafinesque (Dasyatidae) from several localities in Australia. Specimens of this species are readily distinguished from congeners by a unique oncotaxy, with a distinctive basal armature showing only very few rows of billhooks on the basal swelling and a metabasal armature with a dissimilar number of hooks in opposing principle rows (i.e. 8 and 10 hooks). The latter characteristic was not included in the original description of the species, where the opposing hook rows were described to consist of eight hooks each.

Morphological observations of the type-series, voucher specimens and new material of P. butlerae revealed similarities to one of its congeners, P. macracantha , in morphological features and in metrical data (see Table 1). The latter species was described by Palm (2004) in his monograph on trypanorhynch cestodes. Although several specimens were used for the original description, only the holotype, deposited in the ZMB, was available for study. The single specimen of P. macracantha reported by Campbell & Beveridge (2009) from Pa. atrus from the Wessel Islands (Northern Territory, Australia) has been re-examined. It is badly preserved and the identification is doubtful. Recently, Haseli et al. (2010) have reported P. m a c r a c a n t h a from Pastinachus cf. sephen from the Persian Gulf (26º15’– 27º07’N, 52º53’– 56º28’E). Allegedly, this poorly known species can easily be distinguished from congeners by two to three slender, uncinate hooks on the bothrial surface at the base of each tentacle (see Palm 2004), whereas the other hooks in the most basal tentacular region are not enlarged. Palm (2004) considered the specimens to be closely related to P. odonoghuei . The latter species, however, possesses a basal swelling with hook size increasing towards one greatly enlarged billhook (16–18 in length, base 7–9 long; see Beveridge 1990) in hook row eight on the ʻexternal’ surface of each tentacle, which is also surrounded by enlarged hooks.

Prochristianella butlerae appears as a morphologically variable species in terms of its metric data, with an identical oncotaxy in all specimens observed. Since we consider the hook pattern as one of the main characteristics to differentiate trypanorhynchs at a lower taxonomic level, we tentatively retain P. butlerae as a single species. However, further studies might show a polyphyletic nature of P. butlerae on molecular grounds. The metric data for P. m a c r a c a n t h a fall within the values for P. butlerae (see Table 1). Prochristianella macracantha possesses three slender, uncinate basal hooks on the bothrial surface of each tentacle. Observation of the type material of P. butlerae also revealed three enlarged, uncinate hooks on the bothrial surface of the basal tentacular armature, which were not mentioned in its original description (see Beveridge 1990). Of all the specimens observed, these basal hooks differ in size. The basal hook in the middle is slightly displaced anteriorly and usually represents the largest hook. The other two basal hooks are at the same level and are of almost the same size. The principle hook rows in the metabasal armature of P. macracantha start on the antibothrial surface and terminate on the bothrial surface. In the original description of P. butlerae , hook rows were described to commence from the internal towards the external tentacular surface (see Beveridge 1990). Later, Beveridge & Jones (2000) amended this feature and in accordance to Heinz & Dailey’s (1974) description of P. fragilis considered hook rows of P. b u t l e r a e, P. clarkeae and P. mooreae to start on the bothrial and to finish on the antibothrial surfaces. However, all specimens of P. butlerae observed in the present study reveal an orientation of the principle hook rows from the antibothrial to the bothrial tentacular surfaces, identical to that in P. macracantha . In addition, the billhooks on the basal swelling of each tentacle are of similar shape and size and the numbers of hooks in the metabasal tentacular armature are identical in both species. Prochristianella macracantha possesses a dissimilar number of hooks on both opposing principle rows, as is seen in P. butlerae . The hook number is 8 and 10 on opposing rows, rather than 8 to 9 (see Palm 2004). The strongly recurved hooks 3(3’)–6(6’) of P. macracantha are considered to represent intraspecific variation. The number and distribution of testes as stated for P. macracantha are similar to P. butlerae . Prochristianella macracantha possesses 58–62 testes, with 28–31 being located anterior to the genital opening, whereas P. butlerae has 40–58 testes, 30–46 of which are preporal. The ovarian lobes are of a similar size in both species. There appear no significant differences between the oncotaxy and morphological features of P. butlerae and P. macracantha . Based on these findings we consider P. macracantha a new synonym for P. butlerae .

continued.

P. m a c r a c a n t h a

Present study Palm, 2004 Haseli et al., 2010

Range N Range** Range** N Mean SL 1,650 1 1,425 1,214–1,601 4 1,362 PBoL 190* 1 200–250** 209–294 4 248 PVaL 1,050 1 1,175–1,225** 747–966 4 867 PBuL 600 1 575–580** 411–588 4 502 BuL 580–590 2 575–580** 380–576 4 487 BuW 75 2 70–75** 49–146 4 92 BaHL 11–13 4 14 –15** 14–17 4 16 BaHB 5–7 3 7–9** 7– 11 4 9 BiHL 5 2 5–6** 5 4 5 BiHB 6–7 2 9–10 ** 8– 10 4 9 Ratios

PBo: PVa 1.0: 5.5 1 – 1.0: 3.5 4 – PBo: PBu 1.0: 3.2 1 – 1.0: 1.7 4 – BuW: BuL 1.0: 7.7–7.9 2 1.0: 7.7–8.3 1.0: 5.3 4 – *, pars bothrialis twisted. **, numbers unknown.

Seven new host records are provided, which increase the known host range of P. butlerae to a total of 10 different batoid species. In addition, the geographical distribution of this species is greatly expanded, with three additional records from Malaysian Borneo, one from Indonesia (type-locality of P. macracantha ), one from the Persian Gulf (formerly of P. m a c r a c a n t h a) and four records from northern Australia. This makes P. butlerae a common species in Australian waters, with one of the most widespread geographical distributions within Prochristianella , through the Indo-Malayan archipelago to the Persian Gulf.