Biuterina jensenae, Mariaux & Georgiev, 2020

Mariaux, Jean & Georgiev, Boyko B., 2020, Cestode parasites (Neodermata, Platyhelminthes) from Malaysian birds, with description of five new species, European Journal of Taxonomy 616, pp. 1-35 : 13-16

Biuterina jensenae sp. nov.

urn:lsid:zoobank.org:act:5B34DD7D-6AA3-43A3-A8B3-6423594ACD3E

Figs 14–21

Etymology

The species is dedicated to our colleague Prof. Kirsten Jensen, University of Kansas, Lawrence, in recognition of her remarkable contribution to tapeworms systematics.

Material examined

Holotype

MALAYSIA • Selangor, University of Malaya’s Gombak Field Station ; 3.32° N, 101.77° E; 280–350 m a.s.l.: 30 Jul. 2010; MHNG-PLAT-121156 .

Paratypes

MALAYSIA • 1 fragment; same collection data as for holotype; MHNG-PLAT-121157 .

Hologenophore

MHNG-PLAT- 121157. Partial COI sequence, Genbank MN590287 .

Other material

MALAYSIA • 3 juveniles from Tricholestes criniger (Blyth, 1845) ( Passeriformes , Pycnonotidae ); same locality as for type material; 5 Aug. 2010; partial COI sequence, Genbank MN590286 ; MHNG-PLAT-121158 .

Type host

Chloropsis cochinchinensis (Gmelin, 1789) ( Passeriformes , Irenidae ).

Description (from type material)

Worm with body of medium size, 36 mm long, with maximum width 1100 at level of gravid proglottides; consisting of 276 proglottides. Proglottides craspedote, wider than long except for very last gravid ones. Scolex poorly delineated from neck, 400 in diameter ( Fig. 14 ). Suckers muscular, rounded, 185–200 (190, n = 4) in diameter. Rostellum discoid, with strong conical anterior extremity, 128 in diameter, 95 in length, musculo-glandular, armed with a double crown of about 42 small triangular hooks of similar size, with short handle, more elongate in anterior row, more massive in posterior row, with reduced or indistinguishable epiphyseal thickenings. Length of anterior hooks 15.5–16 (n = 4), of posterior hooks 15–15.5 (n = 3) ( Fig. 15 ). Neck poorly marked, unsegmented zone extending to 900 from posterior margin of suckers. Genital pores irregularly alternating in short unequal series (e.g., … 5, 1, 1, 1, 3, 7, 1, 2, 1, 2, 1, 1, 2…); situated at anterior 40% of lateral proglottis margin. Ventral osmoregulatory canals up to 120 wide, connected posteriorly in each proglottis by transverse anastomosis. Dorsal osmoregulatory canals 10–15 wide. Genital ducts between osmoregulatory canals. Genital atrium simple, narrow, inconspicuous.

Testes 9–13 in number (11, n = 11), in a single dorso-central field ( Fig. 17 ). External vas deferens forming numerous compact coils situated in median field adjacent to antiporal extremity of cirrus-sac. Cirrus-sac cylindrical to pyriform, straight, thick-walled, not or just reaching excretory canals, 107– 122 × 41–51 (114 × 46, n = 14) ( Figs 16–17 ); internal vas deferens forming a few coils in its proximal half. Cirrus unarmed.

Vitellarium posterior, central, compact and transversely elongate, 90–120 × 35–50 (103 × 41, n =9). Ovary anterior and transversely elongate, poorly visible in our material. Vagina well-marked, with strong wall, opened posteriorly to male pore, then parallel to cirrus sac, straight. Seminal receptacle elongated and discrete, just poral to ovary or partially dorsal to it ( Fig. 17 ).

Uterus starts its development as an antero-dorsal sac, developing into a transverse sac and rapidly forming 2 connected postero-lateral sacs containing developing eggs. Paruterine organ simultaneously formed anteriorly, then progressively posteriorly over uterus. Paruterine organ with compact walls but loose internal tissues. Connecting (transverse) part of uterus widening and developing anteriorly into paruterine organ together with eggs. Eggs eventually passing into fully developed paruterine organ; vestigial uterine sacs empty and progressively disappearing ( Figs 18–20 ). Eggs oval, with thin outer envelope, 35–41 × 25–31 (38 × 27, n = 15) ( Fig. 21 ). Oncospheres 25–30 (26, n = 15). Lateral embryonic hooks 13–14 (13.1, n = 15) long, central embryonic hooks 14–15 (14.7, n = 10) long.

Additional data from juvenile specimens in T. criniger: Scolex diameter 370–385. Sucker diameter 190–217 (198, n = 12). Rostellum 116–135 in diameter, 96–100 in length. Hook number 42–44, 15.5–17 in length.

Remarks

With its distinctive pair of uterine sacs, paruterine organ and typical rostellum, our material unambiguously belongs to the genus Biuterina Fuhrmann, 1902 as defined by Georgiev & Kornyushin (1994). The last review of the group by Georgiev & Mariaux (2007) reported 34 species in the genus and presented an identification key to the species. To our knowledge, no additional species has been reported since this publication. None of the species in this genus is known from Irenidae or Pycnonotidae , and only 3 of them have an Oriental distribution, all of them in India. No species of Biuterina spp. are known from SE Asia yet.

The majority of the known species differ markedly from our material by a combination of their rostellar hook numbers and length (which are mostly both more numerous and longer), resulting in only 2 species showing similar metric characters:

– Biuterina chlorurae (Rausch & Schiller, 1949) , a parasite of Pipilo chlorurus (Audubon, 1839) (Passerellidae) in Wyoming, USA. It differs from our material by showing fewer proglottides (140 vs 276), slightly longer (up to 20) rostellar hooks in two rows differing in length and shape, smaller seminal receptacle (20 in diameter), different development of the uterus (with uterine sacs not clearly separated) and larger eggs (43–50 in diameter).

– Biuterina dicruri Singh, 1964 , from Dicrurus leucophaeus Vieillot, 1817 (Dicruridae) in North-East India. Its rostellar hooks are of different length on both rows. Although the testis number in this species overlaps that of our specimens, it most commonly has 7 testes against 11 on average in our material and its cirrus pouch is shorter (80–110 × 26–40).

The differences listed above, together with clearly different hosts and distributions lead us to place our material in a new species that we name Biuterina jensenae sp. nov.

We are well aware that, ideally, more material would be desirable to describe this species. However, given the unambiguous characters considered and the fact that access to these parasites is extremely scarce, we think it is worth taking the opportunity to describe and name it, even if additional information, especially concerning the variability of the metrical data, is to be provided when more specimens are available.

Specimens from T. criniger are juvenile and therefore not included in the type series. Their observable characters, especially the shape and organization of their rostellum and hooks, are, however, very similar to those of B. jensenae sp. nov. Unless access to fully developed specimens shows otherwise in the future, we consider them conspecific.

Figures

Figs 14–21. Biuterina jensenae sp. nov. 14. Scolex. 15. Rostellar hooks (I: anterior; II: posterior; a: from holotype; b: from Tricholestes criniger (Blyth, 1845)). 16. Cirrus-sac. 17. Mature proglottis, dorsal view. 18–20. Various stages of paruterine organ development. 21. Egg. Scale bars: 14, 17–19 = 100 µm; 15 = 10 µm; 16 = 50 µm; 20 = 250 µm; 21 = 20 µm.