Gobifaustula, Dronen & Blend & Mohammed & Bannai, 2021

Dronen, Norman O., Blend, Charles K., Mohammed, Essa T. & Bannai, Majid, 2021, Reconsideration of the species assigned to Faustula Poche, 1926 (Digenea: Microphalloidea) with the proposal of five new genera in the Faustulidae Poche, 1926, Zootaxa 5027 (2), pp. 231-253 : 242

Gobifaustula n. gen.

( Fig. 6 )

Type species: Gobifaustula qikouensis (Qiu & Li in Shen & Qiu, 1995) n. comb. Type and only species.

(Syn. Faustula qikouensis Qiu & Li in Shen & Qiu, 1995)

Diagnosis: Body small, somewhat pyriform (see fig. 26 of Qiu & Li 1995 in Shen & Qiu 1995); tegument aspinose. Forebody occupies less than one-half of body length. Oral sucker subterminal, muscular, nearly circular, somewhat globular. Ventral sucker muscular, larger than oral sucker, located well anterior to midlevel of body. Prepharynx short to absent. Pharynx small, oval, muscular. Esophagus, simple, relatively long. Intestinal bifurcation largely in forebody immediately anterior to ventral sucker which may overlap posterior aspect of bifurcation and located well anterior to midlevel of body. Ceca relatively short, terminate about midlevel of body. Testes 2, spherical, entire, symmetrical, contiguous on midline of body, located near midlevel of hindbody. Cirrus sac claviform, surpasses ventral sucker posteriorly by short distance; seminal vesicle originally described as saccular but may be bipartite (see fig. 26 of original description by Qiu & Li 1995), occupies slightly more than one-half of cirrus sac; details of cirrus, ejaculatory duct, pars prostatica unknown. Genital pore median or nearly so, immediately anterior to ventral sucker at juncture of esophagus and intestinal bifurcation. Genital atrium unknown. Ovary pretesticular, intercecal, trilobed in form of triangle, located immediately right of and contiguous with left cecum, occupies area from about midlevel of cecum posteriorly to short distance anterior to level of cecal ends. Laurer’s canal unknown. Seminal receptacle contiguous with posterior end of and nestled between posterior 2 lobes of ovary. Vitelline follicles distributed in 2 clusters, 1 on each side of body from about midlevel of ceca or anterior margin of ovary to cecal ends. Uterus occupying bulk of posttesticular space, extends from level of testes to near posterior extremity. Eggs numerous, small, operculate. Excretory vesicle and extent of excretory arms unknown; excretory pore terminal to somewhat dorsally located. Reported as intestinal parasites of gobiid fishes in freshwater tributaries entering the Yellow Sea.

Etymology: The genus is named based on the type of fish (goby; Latin gobio) infected by Gobifaustula qikouensis and its similarities to members of the Faustulidae (Faustula) .

Remarks: Faustula qikouensis (= G. qikouensis ) was described from the Asian freshwater goby, S. ommaturus ( Perciformes : Gobiidae ), from near the mouth of a river that opens into the Bo-Hai Sea (considered to be the more inland portions of the Yellow Sea of China). It is similar to species of Faustula by having relatively small suckers where the ventral sucker is slightly larger than the oral sucker; gonads that are in the hindbody; a uterus that reaches posterior beyond the testes, mainly concentrated in the hindbody; a median to slightly submedian genital pore; a cirrus sac that overreaches the ventral sucker, surpassing it by a short distance posteriorly and a ventral sucker that is not close to the posterior extremity (located near the posterior aspect of the anterior one-third of body). It differs from species of Faustula by having a somewhat pyriform, aspinose body that is markedly tapered anteriorly and broadly rounded posteriorly; a ventral sucker that overlaps the intestinal bifurcation anteriorly; a relatively long hindbody (approximately 60% of the body length); side by side, contiguous testes that are located near the midlevel of the hindbody well posterior to the ventral sucker; a genital pore opening anterior to the intestinal bifurcation near the posterior end of the esophagus; a cirrus sac that encloses a bipartite seminal vesicle; vitelline fields that are in 2 clusters composed of relatively few follicles (6–7/side) that are confined to the middle one-third on each side of the body and a pretesticular, trilobed ovary. Bray (2008 b) suggested that this species does not belong in Faustula and probably should be transferred to Bacciger Nicoll, 1914 ; however, only species of Allofellodistomum Yamaguti, 1971 ; Baccigeroides Dutta, 1995 ; Echinobreviceca Dronen, Blend & McEachran, 1994 ; Paradiscogaster Yamaguti, 1934 ; Triganocryptus Martin, 1958; and Yamagutia Srivistava, 1937 have a pretesticular ovary, but none of these genera contain species where the ovary is lobed. Based largely on the combination of the above characteristics, especially the definitely trilobed, pretesticular ovary and a bipartite seminal vesicle, we feel that F. qikouensis is most similar to species of Baccigeroides . Since no species assigned to Baccigeroides as currently diagnosed has a lobed pretesticular ovary, we propose the erection of Gobifaustula to support Gobifaustula qikouensis (Syn. F. qikouensis ) (see fig. 26 of Qiu & Li 1995 in Shen & Qiu 1995).

Figures

FIGURES 5–6. Diagrammatic illustrations of faustulids (ventral views): 5. Faustula gangetica (Srivastava, 1935) Yamaguti, 1958 based on Srivastava (1935). 6. Gobiofaustula qikouensis (Qiu & Li, 1995) n. comb. based on Qiu & Li (1995); representative of Gobiofaustula n. gen.