New record of Anaticola mergiserrati ( Phthiraptera : Ischnocera : Philopteridae ) from Sindh Province , Pakistan , with its detailed morpho-taxonomy

During the chewing lice examination on ducks for the genus Anaticola Clay, 25 ducks of five species (5 birds for each species) were examined from different water bodies of Sindh Province of Pakistan. A total of 65 specimens of chewing lice of genus Anaticola were collected including two species, A. crassicornis (Scopoli, 1773) and A. mergiserrati (De Geer, 1778) from only two species of ducks, common teal Anas crecca (L.) and common pochard Aythya ferina (L.). It is recovered for the first time from a duck of the genus Anas, which make the new host record in the world and first time reported from Pakistan making new country record.


Introduction
Family Anatidae includes the group of water birds like ducks, geese and swans, which are resident as well as migratory birds in Sindh, Pakistan and other parts of the world near natural or artificial water bodies and also grain fields [1-3].These birds harbor a variety of chewing lice, reported throughout the world, mainly represented by 9 genera of chewing lice [4-9].The genus Anaticola Clay is specific mainly to the birds of order Anseriformes but also found on flamingoes (order Phoenicopteriformes).It is a large genus with 37 species parasitizing Anatid birds worldwide [5, 9, 10], with more elongated and narrow body.After Clay [10], this genus has been remained contradict in its taxonomical description with in species, however it has been considered as inquirenda and need to explicit its recognized characters [11][12][13][14][15]. Amongst all species of this genus only three species have been found on various bird species of the same subfamily within the family Anatidae, for instance A. anseris (L.), A. mergiserrati (de Geer) and A. crassicornis (Scopoli), A. mergiserrati is known from 16 species, mainly from the tribe Aythyini (subfamily Aythyinae) and tribe Mergini (subfamily Anatinae) but not yet reported from tribe Anatini (subfamily Anatinae) [9, 13, 16 -18].
In present study, the two species of genus Anaticola were found from a variety of ducks and it was first time that Anaticola mergiserrati was reported from a ducks species of genus Anas.During identification process, it was very difficult to determine the species especially when both closely related species of Anaticola were collected from same bird i.e.Anas crecca and Aythya ferina, hence it was considered a deep necessity to redescribe the present species.Previously from the same region Naz et al., [13] have reported and highlighted the morphotaxonomical characters of A. crassicornis.The morpho-taxonomical features of A. mergiserrati are rarely found scattered in the previous literature [19,20] and it was seemed a necessity to elucidate it.Therefore the detailed morpho-taxonomy of this species was needed to be elaborated in present with special reference to the male and female abdominal terminalia and male genitalia, especially when the two species of Anaticola were found together in a host.

Materials and methods
Total of 25 birds of different ducks of five species, Anas crecca, Anas clypeata, Anas platyrhynchos, Aythya ferina and Aythya fuligula were collected for the examination of their chewing lice mainly for the genus Anaticola from different water bodies of Sindh, Pakistan.Chewing lice were collected from ducks during October 2016 to April 2017, as this is the peak time for the migration of ducks from northern hemisphere to Pakistan.The methods for collection of chewing lice were followed those of Naz, et al. [13] and Naz [21].The preservation and slide mounting of the chewing lice specimens was followed as prescribed in literature [22,23].Drawings were made with the aid of a drawing tube attachment Olympus-UDA.For observation of genitalia, ten mature specimens were kept in 10% KOH solution in hot water for 8-10 hours and their genitalia were dissected and examined.The specimens then were pinned in micro-vial containing glycerin and deposited at the Museum Collection of Advanced Parasitology Research Laboratory (APR Lab), Department of Zoology, University of Sindh, Jamshoro.The following parasitological parameters were evaluated: (1) prevalence-the proportion of members of host taxon infested with ectoparasites; (2) intensity-the number of individuals of a chewing lice species on the infested hosts; (3) abundance Range-the minimum and maximum number of individual louse species found on particular host species; (4) Standard Deviation in lice species on both positive hosts.

Preantennal region
Narrow, longer than broad, rounded and smooth slightly sloped hyaline margin evident with horizontal furrows, marginal carina broken laterally, bearing three pairs of fine antero-lateral marginal setae and one pair of blade like seta present; marginal carinal nodus present; dorsal carina absent; pulvinus completed and surrounded with ventral carina.Antennal region Antennae heteromorphic (Figure 5), filiform; scape of male much elongated than female antenna, bearing partially sclerotized texture on it, with three median submarginal fine setae; segment II and III with thumb like lateral process; segment IV short bearing two discoidal sensillae and terminal conical sensillae; conus short and blunt, with anterior seta.

Postantennal region
As broader as long, slightly narrower at posterior, temples rounded and smooth, temporal marginal carina thin, temporal setae (ts) five small microstate with ts1, 2, 4, 5 microsetae and ts 3 normal seta but short in size; temporal median seta absent;  Female Terminalia (Figure 10) Female genital opening ventro-terminal, vulval margin slightly convex and wavy, subgenital plate not deeply concave, with latero-posterior corner without seta; inner margin of vulva bearing a small row of 5-6 marginal microsetae and 8 median microsetae on subgenital plate, terminal segment slightly concave posteriorly.5).

Meso-sternal plate
Meso-metasternal plate very weak; two pairs of microsetae present on the anterior and posterior margins of the mesometasternal plate.
Meso-meta sternal plate fused, wide, diamond shaped, bearing one pair of seta on anterior edges and one pair of seta at posterior (Figure 7).

Thorax
Prothorax short and Pterothorax long and narrow.
Pterothorax slightly partially divided at posterior margin.
Prothoracic and Pterothoracic segment are similar as in A. crassicornis.Only the difference is shoulders of pterothorax are wider in A. mergiserrati than that of A. crassicornis

Abdomen
Comparatively wider, oblong to elongate.Pleurites thin and less sclerotized; subgenital plate of female wide and long, deeply concave at median, bearing 6 pairs long fine setae and 2 pairs microsetae at posterior vulval margin.Male terminalia chaetotaxy as in Figure 9.
Narrower, elongated, slender.Pleurites thick and sclerotized; subgenital plate wide and short, shallowly concave, bearing 5 pairs of short spinous setae with large alveoli at vulval margin.Male terminalia chaetotaxy as in Figure 8.

Genitalia
Extending up to abdominal segment IV. Parameres short and narrow.Mesomere long, relatively wider, bearing two peg like setae, penis Y-shaped anteriorly thick with clearly bifurcated anterior end and posteriorly slightly curved, measuring 0.223-0.244mm.Lateral sclerites of endomere weak or absent (Figure 12B).
Extending up to abdominal segment III.Longer than the genitalia of A. crassicornis.Parameres long and narrow, extending behind basal apodeme.Mesomeral sclerite short and narrow; penis Y-shaped with anteriorly short bifurcation and thin and posterior end prominently curved, measuring 0.143-0.147mm(Figure 12A).

Table 1 . Prevalence, Range, Intensity and male and female ratio of the two species of genus Anaticola recovered from A. crecca and A. ferina during present study
*A.c.Anaticola crassicornis; A.m. Anaticola mergiserrati