TENTACULARIID TRYPANORHYNCHS FROM THE NHM 



149 



nehereus, Houghly estuary, India. Other postlarvae identified as H. 

 minima sp. nov.: BMNH 1980.6.23.13 from Polynemus sp.; 

 1980.6.23. 14, A. Roy leg., Polynemus sp., Houghly estuary, India (4 

 postlarvae); 1992.7.1.189 from Harpodon nehereus; 1992.7.1.190- 

 192, A. Roy leg., Polynemus paradiseus. Sugar Island, Bay of 

 Bengal (5 postlarvae). 



DESCRIPTION. With the characters of the genus Heteronybelinia. 

 The scolex of the holotype as well as the scolex and basal and 

 metabasal tentacular armature of a specimen from P. paradiseus are 

 shown in Figs 34 and 35-38 respectively. The scolex is small, 

 differing in size and shape between specimens. Measurements (from 

 types 1980.12.2.1): SL=706, 926; SW=386, 642; pbo=427, 454; 

 pv=267, 397; pb=200, 252; app=280, 270; vel=84, 186; BL=191 

 (187-200), 237 (229-252); BW=54 (43-66), 83 (74-89); BR=3.5: 1 , 

 2.9:1; SP=2. 1 : 1 .3: 1, 1.8:1.6:1. The tentacles are long, in inverted 

 condition nearly reaching the apical end of the bulbs, with a TW=23- 

 28; TW increases towards the tip of the tentacles, a basal tentacular 

 swelling is absent. Prebulbar organs and muscular rings around the 

 basal part of the tentacle sheaths are absent. The retractor muscles 

 originate at the base of the bulbs (Fig. 34). 



The tentacular armature is homeoacanthous, heteromorphous and 

 a characteristic basal armature is absent (Figs 36-38). The hooks 

 diminish in size towards the basal part of the tentacle, the form of the 

 hooks differs from compact and rose-thorn shaped (bothridial) to 

 falcate hooks with a stout base (antibothridial). The hook size in the 

 metabasal armature ranged between L=20.8-24; B=15.2— 16.8 

 (bothridial) and L=24-27.2; B=5.6-7.2 (antibothridial), and the 

 hook size in the basal part of the tentacle was between L=12— 17.6; 

 B=7.2-12 (bothridial) and L=15.2-17.6;B=7.2-8.8 (antibothridial); 

 hsr=6. 



ETYMOLOGY. The new species is named for its small size. 



Remarks. H. minima sp. nov. is easily identifiable by its small 

 scolex size and the characteristic tentacular armature. The present 

 specimens from Harpodon nehereus, Polynemus paradiseus and 

 Polynemus sp. clearly demonstrate a heteromorphous armature, 

 where the hook form changes from rose-thorn shaped to falcate 

 hooks, giving the tentacles a heteroacanthous appearance. However, 

 the quincunx formation of the hooks is still recognisable. The 

 absence of a characteristic basal armature places the species in 

 subgroup IIAa of Palm et al. (1997). 



14. Heteronybelinia robusta (Linton, 1890) (Figs 3<MU) 



Material examined. BMNH 1976.11.5.42-43, R. van der Elst 

 leg., 1 adult from the gut of Carcharhinus limbatus. South Africa. 

 Additional material: USNPC 7727, E. Linton leg., 3 adults from 

 Dasyatis centroura. Woods Hole, USA. 



Description (Figs 39-41). With the characters of the genus 

 Heteronybelinia. Measurements: SL=1020; SW=699; pbo=510; 

 pv=377; pb=257; vel=294; BL=246 (233-257); BW=82 (79-84); 

 BR=3:1; SP=2: 1.5:1. The tentacles are slender, and increase in 

 width towards the metabasal and decrease towards the apical part of 

 the tentacle; TW=24-30; a basal swelling is absent. The tentacle 

 sheaths have two spiral coils; TSW=24-27. Prebulbar organs and 

 muscular rings around the basal part of the tentacle sheaths are 

 absent. The retractor muscles originate at the basal part of the bulbs. 

 The tentacular armature is homeoacanthous, heteromorphous and 

 a characteristic basal armature is absent. The form of the hooks 

 changes slightly from compact and rose-thorn shaped (bothridial) to 

 more slender hooks with a stout base (antibothridial) (Fig. 40). The 



hook size in the metabasal armature ranged between L=l 1.7-12.5; 

 B=7.2-9.2 (bothridial) and L=l 3.0-14.0; B=5.6-7.2 (antibothridial), 

 and hooks of the basal part of the tentacle (Fig. 41) were minute, 

 between L=5.6-7.2; B=5.6-7.2 (bothridial) and L=4-5.6; B=4-5.6 

 (antibothridial), continuously increasing towards the tip; hsr=6-7. 

 The strobila of the small specimen consists of 71 acraspedote 

 proglottids. Measurements of the proglottids were as follows: proglot- 

 tid 20: length=48, width=320; proglottid 48: length=140, width=400; 

 proglottid 62: length=490, width=656; proglottid 70: length=610, 

 width=746. Genital pores ventro-lateral, in the anterior third of the 

 proglottids, alternate irregularly; cirrus sac elongate, directed 

 anteromedially, reaching the anterior end of the proglottids. Other 

 internal structures were not seen. 



Remarks. The present specimen corresponds to 3 specimens 

 described as N. robusta by Linton (1924). Scolex measurements and 

 the characteristic tentacular armature lie within the same range. 

 Thus the present specimen is identified as belonging to the same 

 species. However, as the type material of N. robusta is not available 

 at the USNPC, the taxonomy of A 7 , robusta still needs to be clarified. 

 There are several species which have rose-thorn-shaped hetero- 

 morphous hooks along the tentacle. H. robusta differs from all 

 adequately described species due to the small scolex size with 

 minute basal hooks, continuously increasing in size from 5 to 12.5 

 (bothridial) and 4 to 14 urn (antibothridial). The general hook form 

 remains rose-thorn shaped along the tentacles. Thus, the present 

 specimen belongs into subgroup IIAa of Palm et al. (1997). 



15. Heteronybelinia yamagutii (Dollfus, 1960) nov. comb. 



(Fig. 42^4) 



Material examined. BMNH 1976.1 1.5.41, R. van der Elst leg. , 

 1 adult from the stomach of Sphyrna lewini, South Africa. 



Description. Nybelinia yamagutii was described in detail by 

 Dollfus (1960, see figures 1-5) and Palm et al. ( 1997). The follow- 

 ing measurements were taken: SL=2646; SW=1080; pbo=1134; 

 pv=1000; pb=1455; vel=140; BL= 1430 (1418-1455); BW= 236 

 (220-247); BR=6.1:1; SP=0.8:0.7:1. The tentacles are long and 

 slender and deminish in size along the tentacle; TW metabasal=90- 

 98, TW apical=66-75. A basal tentacular swelling is not present. 

 The tentacle sheaths are sinuous; TSW=51-56. Prebulbar organs 

 and muscular rings around the basal part of the tentacle sheaths are 

 absent. The retractor muscles originate in the basal part of the bulbs. 



The armature is homeoacanthous, heteromorphous, and a charac- 

 teristic basal armature with bill-hooks is present. The hooks of the 

 metabasal armature are different in shape and size on bothridial and 

 antibothridial tentacle surfaces. The form of the hooks is described 

 in detail in Dollfus (1960). The hook size in the metabasal armature 

 was between L=69-75 (bothridial) and L=60-65 (antibothridial). 

 The size of the basal hooks was between L=18-23. The bill-hooks 

 were in rows 3-4 with a total length of 41^46. 



The 12.5 cm long worm has a craspedote strobilar with several 

 hundred segments increasing in size (Figs 42-44); last proglottid 

 with rounded proximal end. The size varies in the first 2 cm of the 

 strobila between 70-100 long and 300^120 wide, from 4-5 cm 

 between 195-220 and 780-900 (Fig. 42), from 7-8 cm between 

 360-420 and 1260-1400 (Fig. 43), and at the final proglottids 

 between 360-400 and 1680-1820 (Fig. 44). In mature proglottids, 

 the elongate cirrus sac is directed anteromedially, and alternates 

 irregularly (Fig. 42). Testes often ovoid, in double layer, often not in 

 middle of segments. Testes number per proglottis (62-70 and 80-90), 

 size (40-55 and 50-70 in diameter) and size of vitellaria (13-16 and 

 15-33 in diameter) increases between the first 3 cm and after 7 cm 



