Cruzia americana Maplestone

Panti-May, Jesús Alonso, Chan-Casanova, Anyela Jackelin, Canche-Pool, Elsy, Tello-Martín, Raúl, Ruiz-Piña, Hugo, Concha-Guillermo, Henry, Guiascón, Oscar Retana-, Vega, Pedro Pablo Martínez, Chablé-Santos, Juan, Martínez, Erendira Estrella-, Moguel-Chin, Wilson Isaias, Hernández-Orts, Jesús S., Hernández-Mena, David I., Mendoza-Garfias, Berenit & García-Prieto, Luis, 2024, Morphological and molecular data on helminths of Didelphis virginiana and Philander vossi (Mammalia: Didelphidae) from the Yucatán Peninsula, southeast Mexico, Zootaxa 5463 (1), pp. 1-24 : 7

Cruzia americana Maplestone

Site of infection: Caecum.

Host species: Didelphis virginiana and Philander vossi .

Localities: Mérida, Umán (Yucatán) and Chetumal (Quintana Roo).

Prevalence: Didelphis virginiana 66.7% (4/6), Philander vossi 100% (1/1).

Mean intensity: Didelphis virginiana 273 (range 11‒606), Philander vossi 60.

Specimens deposited: CNHE 12870‒12872.

GenBank accession numbers: PP662455‒PP662457.

Comments: The characteristics observed in studied nematodes agree with the redescription by Li (2019). Cephalic extremity with three small lips, almost equal in size, each with one pair of small teeth at inner margin; dorsal lip with two submedian papillae and each subventral lip with one subventral papilla and one prominent amphid ( Figure 3A ). Male 7,050 ‒14,000 in body length. Pharynx (160‒220 long) armed with three longitudinal rows of 13‒15 pharyngeal lamellae each ( Figure 3B ). Esophagus (1,720 ‒2,500 long) consisting of cylindrical corpus (gradually becoming narrower toward posterior part and forming a small anterior bulb at end), inconspicuous isthmus and terminating in conspicuous valved posterior bulb. Intestinal diverticulum present. Posterior extremity of body slightly curved ventrally, with 11 pairs of caudal papillae (three pairs precloacal, three pairs paracloacal and five pairs postcloacal) plus a single precloacal medioventral papilla ( Figure 3C‒D ). Spicules subequal, 820‒1,060 long. Gubernaculum 140‒205 long with two sharp edges ( Figure 3E ). Female 7,250 ‒16,230 in body length. Vulva slit-like, 3750‒6,900 from the anterior end. Eggs oval, 105‒120 long by 50‒68 wide. According to Li (2019), C. americana can be differentiated from Cruzia tentaculata (Rudolphi) by the number of pharyngeal lamellae, 13‒17 in C. americana and 10 in C. tentaculata . However, these structures are not easy to observe under light microscopy ( Li 2019). In the studied nematodes the exact number of pharyngeal lamellae was observed only by cutting the pharynx. In all C. americana males dissected to examine the pharyngeal lamellae, the gubernaculum had sharp edges. This characteristic was reported by Crites (1956) in C. americana and Adnet et al. (2009) in C. tentaculata , while Li (2019) described a blunt gubernaculum at distal end in C. americana . The taxonomic status of C. americana has been under debate due to the morphological similarities with C. tentaculata . Wolfgang (1951) considered C. americana synonym of C. tentaculata . In contrast, Crites (1956) and, more recently, Li (2019) redescribed C. americana based on newly collected specimens from the type-host D. virginiana in the USA. We agree with the proposal of Li (2019) on the necessity of clarifying the taxonomical relationships of C. americana and C. tentaculata using an integrative approach that includes molecular markers in the future.

Cruzia americana has been recorded from D. virginiana in Colima, Guerrero, Oaxaca, Veracruz ( Monet-Mendoza et al. 2005), and Zacatecas ( Martínez-Flores & Martínez-Salazar 2016). This is the first report of C. americana in the Yucatán Peninsula.

Figures

FIGURE 3. Males of Cruzia americana and Cruzia tentaculata from Didelphis virginiana. A. SEM micrograph of C. americana anterior end, apical view. B. SEM micrograph of internal structures of pharynx (columnar structures of cuticular lamellae) of C. americana, longitudinal section. C. SEM micrograph of C. americana posterior end, lateral view. D. Cruzia americana posterior end, ventral view. E. Gubernaculum of C. americana, ventral view. F. Internal structures of pharynx (columnar structures of cuticular lamellae) of C. tentaculata, longitudinal section. G. Gubernaculum of C. tentaculata, ventral view. Abbreviations: amphid (a), dorsal lip (dl), ventral lip (vl), papillae (p), pharyngeal lamellae (pl), paracloacal papillae (pac), precloacal papillae (pec), poscloacal papillae (poc), single precloacal papilla (spec), teeth (t).