Chewing lice of genus Ricinus (Phthiraptera, Ricinidae) deposited at the Zoological Institute of the Russian Academy of Sciences, Saint Petersburg, Russia, with description of a new species

We revised a collection of chewing lice deposited at the Zoological Institute of the Russian Academy of Sciences, Saint Petersburg, Russia. We studied 60 slides with 107 specimens of 10 species of the genus Ricinus (De Geer, 1778). The collection includes lectotype specimens of Ricinus ivanovi Blagoveshtchensky, 1951 and of Ricinus tugarinovi Blagoveshtchensky, 1951. We registered Ricinus elongatus Olfers, 1816 ex Turdus ruficollis, R. ivanovi ex Leucosticte tephrocotis and Ricinus serratus (Durrant, 1906) ex Calandrella acutirostris and Calandrella cheleensis which were not included in Price’s world checklist. New records for Russia are R. elongatus ex Turdus ruficollis; Ricinus fringillae De Geer, 1778 ex Emberiza aureola, Emberiza leucocephalos, Emberiza rustica, Passer montanus and Prunella modularis; Ricinus rubeculae De Geer, 1778 ex Erithacus rubecula and Luscinia svecica; Ricinus serratus (Durrant, 1906) ex Alauda arvensis. New records for Kyrgyzstan are R. fringillae ex E. leucocephalos and ex Fringilla coelebs. A new record for Tajikistan is R. serratus ex Calandrella acutirostris. The new species Ricinus vaderi Valan n. sp. is described with Calandra lark, Melanocorypha calandra; from Azerbaijan, as a type host.


Introduction
Ricinus De Geer, 1778 (Phthiraptera: Amblycera) is the largest genus of chewing lice found parasitizing Passeriformes [17]. Whereas chewing lice mainly feed on feathers, these lice and occurs on approximately one-third of the 70 families of Passeriformes. Major revisions of this genus were done separately for Old World [20] and New World species [17] and comprise the majority of known species.
Blagoveshtchensky [3] described Ricinus ivanovi Blagoveshtchensky, 1951 and Ricinus tugarinovi Blagoveshtchensky, 1951; he also mentioned additional records of this genus in the former USSR. Although he noted that Calandrella acutirostris acutirostris Hume, 1873 (Passeriformes: Alaudidae) was a host of Ricinus serratus (Durrant, 1906), this was not cited by Price et al. [19]. Price et al. [19] included only reliable sources, but because R. serratus is already known from several alaudid hosts, this prompted us to inspect material acquired by Blagoveshtchensky. These specimens are deposited at the Zoological Institute of the Russian Academy of Sciences, Saint Petersburg (ZISP) and are part of a larger collection, mainly assembled by him during the 1930s through the 1970s.
In this article, we present data obtained from the studies of Ricinus spp. deposited at the ZISP. We include new country records for Azerbaijan, Kyrgyzstan, Russia and Tajikistan.
Knowing that data about the biodiversity of chewing lice within the former USSR were published mainly in Russian and that the existing literature is scarcely accessible, we will refer only to those records we have been able to verify. Accordingly, species of Ricinus recorded so far in Azerbaijan are Ricinus frenatus Burmeister, 1838 ex Regulus regulus buturlini and R. fringillae ex Emberiza schoeniclus [2].

Materials and methods
Chewing lice of the genus Ricinus deposited at the ZISP were examined and described. In this article, we present all Ricinus species found in this collection. Host systematics follow Clements et al. [5]. To each louse species, we added notes as follows: number of females, males, nymphs, host (Order: Family) including common English name, country, location, number of specimens (slide number), date, collector (coll.) and identifier (det.). Slide numbers are equal to accession numbers, but only handwritten catalogues exist. For those slides without slide numbers, we allocated a new slide number in the form MVXY. Notes from slides about locality are rewritten from slide labels while transliterating from Cyrillic to the Latin alphabet without further changes, and we cannot guarantee their validity. Where information may be lacking, this should be considered as a deficiency of information noted by the collector or collection manager. The majority of the examined specimens are in poor condition, mainly due to mounting directly to medium without using any clearing agent prior to mounting. The medium is most likely Canada balsam, but there are no written notes about it. If the case happened to be otherwise, this will be noted below.
Species concept, morphological characters and system of chaetotaxy follow Nelson [17] (see Fig. 2). All measurements are in millimeters and were taken using QuickPhoto Micro 3.0. In order to achieve high quality, drawings were made as vectors using Adobe Illustrator C6.
The newly described chewing louse species is attributed to the first author.

Results and discussion
In total, we examined 107 specimens of the genus Ricinus mounted on 60 slides and no samples in fixatives were found. The majority of these specimens (78) are females, with only 7 males and 22 nymphs. Specimens had been collected from various locations and by several collectors. Specimens from Tajikistan had mostly been examined and data presented by Blagoveshtchensky [3]. Studies of lice obtained in Azerbaijan have also been published [2], with the exception of Ricinus sp. from Melanocorypha calandra. As expected, the sex ratio is unbalanced (1-11.14) and our results correspond with Nelson [17]  Remarks: Grube [8] reported Physostomum mystax (junior synonym of R. elongatus) on T. ruficollis. Balát [1] in his study, cited Grube [8] and included T. ruficollis as a host of R. elongatus without examining any material. In revision of Ricinus occurring in the Old World [20], Rheinwald did not report any notes about this association and this is probably why it was not cited by Price et al. [19]. We have unfortunately not been able to check Grube's notes and assume that specimens are not available for study. Having previous unreliable reports and only one specimen in this collection creates an aggravating circumstance. However, R. elongatus is known as a parasite of   Remarks: Blagoveshtchensky [3] based his description of R. ivanovi on 1$. Unfortunately, Blagoveshtchensky did not provide a slide number. Neither Rheinwald [20] nor Nelson [17] examined the type specimen. The specimen examined in this study has the same notes about locality and date as given in the original description. Accordingly, this specimen is designated a lectotype specimen of R. ivanovi. Nelson [17] examined 8$ and 3# of R. ivanovi ex Leucosticte tephrocotis (Swainson, 1832) and none from L. brandti. Nelson's record was included by Emerson [6] in a chewing lice checklist of North America. Nevertheless, this was probably missed accidentally by Price et al. [19]. Remarks: Chewing lice on C. a. acutirostris and G. cristata in Tajikistan have been recorded [3]. The record of R. serratus ex C. a. acutirostris was not provided in the checklist by Price et al. [19]. Ricinus serratus is known from 14 species of birds from three families of which nine species belong to the family Alaudidae [19]. The world checklist [19] included two hosts from the genus Calandrella and besides C. a. acutirostris, the records for Calandrella cheleensis (Swinhoe, 1871) recorded by Mey [15] were missed. Mey had found only two nymphs [15] and that could possibly be the reason for excluding the record from the checklist. Nevertheless, even juvenile instars of R. serratus are easily distinguishable from other Ricinus species by the presence of unique serrated pleural nodi. We suggest C. a. acutirostris and C. cheleensis be considered as valid hosts of R. serratus.

Ricinus subdiffusus Nelson, 1972
Ricinus subdiffusus Nelson, 1972 Remarks: This specimen was examined and mentioned by Blagoveshtchensky [4]. Remarks: Blagoveshtchensky [3] based his description of R. tugarinovi on 2$, but he did not provide a slide number for the type specimen. Subsequently, Rheinwald [20], in his revision of the Old World species of Ricinus, re-described R. tugarinovi without examining the type material. Since the specimen examined in this study shares notes about locality and date with two specimens examined by Blagoveshtchensky [3], and inasmuch as we lack information on where the other specimen is deposited, the remaining specimen mounted on slide no. 153 is designated as a lectotype.  Table 1).
Etymology: This species name is derived from Darth Vader, a fictional character in the Star Wars trilogy. The first author's fiancée noticed a similarity between the head of the R. vaderi and Darth Vader's helmet.
Authorship: Note that the authors of the new taxon are different from the authors of this paper; Article 50.1 and Recommendation 50A of the International Code of Zoological Nomenclature [12].
Description: Female (n = 2). Head wider than longer, with characteristic shape as ( Fig. 2A); frons convex with rounded lateral margins, bearing dorsally pair of df setae and marginally 10 f setae; margin not continuous with that of marginal carinae. Lateral margin broadly concave. Temples expanded, outer margin curves inwardly, ending without hook-like structure; t3 one half the size of t1 and t2. Setae a1 short, each associated with two sensillae; a2 positioned marginal; a3 absent. Lunar nodi present, twice the size of tentorial nodi. Setae along antennal lappets reduced and create diastoma, numbers vary in range 6-9 with 3-4 setae associated with po setae. Preantennal setae spinose. Setae m4 same size as pa setae. Mandibles as in Figure 2D, monomorphic without finger-like extension. Ovoid sclerite round, compact with deeply pitted ornamentation. Labrum with setal pattern as in Figure 2A, pair 4 positioned slightly anteriorly to other setae in posterior row. Labium with 13 setae and pattern as in Figure 2A. Mental setae longer than maxillary setae; maxillary palpi genticuloid, extending past edge of head; maxillary plate sausage-shaped, relatively narrow. Gular plate as in Figure 2A with extensions reflexed outwardly; bearing two setae on each side. Thorax (Fig. 2B). Setae L3 and L4 slightly pilose, one L6 seta and small seta L9. Prosternal plate without nodi, pear-shaped; prosternal setae narrowly separated (0.04 mm).
Two tactile setae on coxa I. q2-q4 large and spinose, q4 sometimes absent; w series composed of four setae with anterior two spinose and twice as large as posterior two pilose setae; c1 spinose and larger than c2; c2-c4 pilose. Sternal plate as in Figure 2B bearing one moderately long posterior seta and two or three short anterior setae.
Terminal segments of abdomen as in Figures 2C and 2E. Chaetotaxy in segments II through VII follow Ricinus pattern, two setae with inner less than half the length of the outer. One pair of long setae on sternite VIII and one vulval seta. Setae in anal fringe: ADF, 41-42; AVF, 42-43. Ventral pleural chaetotaxy as in Figures 2C and 2E: II, SSS; III, sss; IV, SIS; V, iIi; VI, iIi; VII, iIi and VIII, iIi. Terminal setae as in Figure 2C with small outer pair of setae, followed by two long setae, and two pairs of small inner setae. Pleural nodi unique (Fig. 2E).
Dimensions as follows: total length = 3.73-3.82; total width = 1.11; head length = 0.72-0.73; head width = 0.83; HI = 86-87 (head index = ratio of head length to head width · 100); labrum width = 0.36-0.37; prothorax length = 0.39-0.40; prothorax width = 0.73-0.75; distance between prosternal setae = 0.039-0.040. Alauda arvensis (L., 1758) 2 + Ricinus sp. 1 Buteo lagopus (Pontoppidan, 1763) 1 + Ricinus sp. 1 Strix Diagnosis: Our specimens of R. vaderi have ornamented ovoid sclerites, present only in the diffusus, serratus and subangulatus species groups. Ricinus vaderi cannot be placed into any of these groups. In the subangulatus species group, the frontal margin is continuous with that of marginal carinae, but not in R. vaderi n. sp. or the diffusus and serratus species groups. Ricinus vaderi n. sp. has a characteristic head shape with broadly concave lateral head margins; the head is wider than the length (HI = 86-87); setae along the antennal lappets are reduced with diastoma; the setal pattern on the terminal tergite iiIIi · iIIii. In the diffusus species group, the lateral margin is almost straight; HI is 100-110, with the exception of R. thoracicus (HI = 93); there is no reduction or diastoma along the antennal lappets and the pattern on terminal tergite iIIim · miIIi (where ''m'' means moderately long seta). Ricinus serratus, the only member of its group, has serrated pleural nodi, the head has a postfrontal constriction, the gular plate has no posterior extensions, the a1 setae are long and there is one tactile seta on coxa I.
Remarks: The condition of these specimens is poor and we were not able to identify them. These two specimens differ from R. serratus, the only known Ricinus from this host species, in not having a laterally positioned, serrated structure on the pleurites.