Penis Morphology Research Articles

Two new species of Caribbiantes, with the redescription of the type species and a review of male genital patterns in Antillean Stenostygninae (Opiliones: Laniatores: Biantidae)

Caribbiantes cubanus Šilhavý, 1973, type species of genus Caribbiantes Šilhavý, 1973, is redescribed based on abundant material from the type locality, providing new data on its morphological variability and penis morphology. Two new species of Caribbiantes are described, C. obtusus sp. nov. and C. barbai sp. nov., based on additional specimens from central and eastern Cuba, for which we give information on their geographical distribution, intraspecific variability and habitat. A new diagnosis for Caribbiantes and updated geographic distributions of the included species are provided. The sexually dimorphic glandular structures on the metatarsus III of males for all Caribbiantes species are described. Male dimorphism, most evident in the robustness of the chelicerae, is reported for the studied species. The male genitalia patterns of Antillean stenostygnines species are described. The phylogenetic affinity of Antillean stenostygnines with Stenostygnus Simon, 1879, a genus from the north of South America, is discussed based on some morphological traits.

Impact of maternal stress on metabolism and penile morphology in young offspring rats.

Exposure to prolonged stress in pregnancy and/or lactation can lead to the future development of diseases. We aimed to study the effects of maternal stress on the biometry, metabolism, and penile morphology of young Wistar rats. Animals were divided into two experimental groups: Control Group (C) - pups from control mothers, without any intervention (n=5); and Chronic Stress Group (S) - pups from mothers who suffered variable stress in the third week of pregnancy (14th to 21st day; n=5). Food intake and body mass of the pups (n=10, in the C group and n=9 in the S group) were checked; at euthanasia (three months old), fat deposits and penis were removed. At birth and weaning, S animals were lighter than C animals, [-33.72% (p=0.0422) and -17.07% (p=0.0018)], respectively. However, the final body mass and body mass delta showed no differences. Food intake and fat deposits also did not differ. However, the S group was hyperglycemic at 30 and 60 days of life [+20.59% (p=0.0042) and +14.56% (p=0.0079), respectively], despite the glycemia measured at 90 days showing no difference between groups. Penile areas and surface densities of the corpora cavernosa components were similar between groups. The results indicate that maternal stress is an important metabolic programmer, which generates low birth weight and accelerated recovery of body mass after birth (catch-up). However, in an early analysis (90 days of life), exposure to gestational stress did not change the morphology of the offspring's penis in adulthood.

Two invalid genera in the family Bythinellidae Locard, 1893 (Caenogastropoda: Truncatelloidea)

Within the genus Bythinella Moquin-Tandon, 1856, with about 250 nominal species, the separation of several genera would be helpful in understanding the phylogenetic relationships between these snails, but neither morphology nor molecular loci studied so far can be used to distinguish any natural taxon over the range of species within this genus. Apart from Bythinella there are two other genera listed in the Bythinellidae by WoRMS: Terrestribythinella Sitnikova, Starobogatov et Anistratenko, 1992, and Strandzhia Georgiev et Glöer, 2013. Considering the cytochrome c oxidase subunit I (COI) sequences, as well as poor morphological data, Terrestribythinella should be considered a junior subjective synonym of Bythinella. In the case of Strandzhia, both COI and 18S sequences studied by us, as well as morphology re-examined (misinterpretation of the penis morphology in the original description) clearly show the assignment of Strandzhia to the genus Grossuana Radoman, 1983, thus Strandzhia becomes a junior objective synonym of Grossuana.

Integrative taxonomy supports one rather than several species of Palingenia in South-Eastern Europe (Insecta, Ephemeroptera, Palingeniidae)

Palingenia Burmeister, 1839, is a small but intensively debated genus of mayflies due to the controversial taxonomy of the species belonging to it. Once widespread throughout Europe, Palingenia longicauda (Olivier, 1791), an iconic species of large pristine rivers, has lost most of its original range, but conservation efforts are greatly hampered by its morphology, which is similar to the sympatric P. fuliginosa (Georgi, 1802) and the peripatric P. sublongicauda Tshernova, 1949. Based on the revision of Soldán’s original collection, supplemented with fresh material from southeastern Europe, we analyzed 213 adult male specimens from 15 different locations from the presently known distribution area of Palingenia in Europe. Principal Component Analysis (PCA) based on the morphometry results of penis morphology and eye distances showed no significant differences among the analyzed populations. Further, the mtCOI barcode sequence data of 73 individuals from the known range of Palingenia species in southeastern Europe represented highly similar populations genetically, with no differentiation. These results show the presence of only one species in southeastern Europe, P. longicauda, thus disproving the distribution of P. fuliginosa in this region. The taxonomic status of P. sublongicauda remains doubtful, as no type material or fresh material from the locus typicus of the species was available for this study. A comprehensive revision of Palingenia, including additional species from Asia and the Indomalayan regions, is highly recommended to reevaluate the species composition of Palingenia and detect the most closely related taxa of the single P. longicauda in Europe.

A new genus and new species of springsnails (Gastropoda, Hydrobiidae) from North-East Morocco

Recent field surveys on snails conducted in the oriental region of Morocco have led to the discovery of a new species belonging to a new genus, described here as Znassela bnisnasensis gen. et sp. nov. It can be distinguished from the other hydrobiid snails by the morphology of the shell and male anatomy. The new hydrobiid snail differs mainly by its elongated ovate shell with 4.5 whorls, slightly convex with a shallow suture, and by the penis showing a swelling near the penis tip; the latter has two penial appendices located on the same side. Znassela bnisnasensis has been found in the Béni-Snassen massif, considered a Protected Area in the north-eastern part of Morocco and which is a Site of Ecological and Biological Interest (known as SEBI or SIBE). Photographs of the holotype and paratypes are presented, with the penis morphology, habitat and information on its autecology.

Testing Morphological Relationships Between Female and Male Copulatory Structures in Bats.

The lower reproductive tract of female mammals has several competing functions including mating, tract health maintenance, and parturition. Diverse vaginal anatomy suggests interactions between natural and sexual selection, yet despite its importance, female copulatory morphology remains under-studied. We undertook a comparative study across the species-rich mammalian order Chiroptera (bats) with a focus on the suborder Yangochiroptera (Vespertilioniformes) to examine how female vaginal features may have coevolved with male penis morphology to minimize mechanical damage to their tissues during copulation. The penis morphology is diverse, presenting great potential for post-copulatory sexual selection and coevolution with the female morphology, but vaginas have not been carefully examined. Here we test the hypotheses that vaginal thickness and collagen density have coevolved with features of the male penis including the presence of spines and a baculum. We present histological data from females of 24 species from 7 families of bats, and corresponding data on male penis anatomy. We also examine the role of phylogenetic history in the morphological patterns we observe. We found evidence that female vaginal thickness has coevolved with the presence of penile spines, but not with baculum presence or width. Collagen density did not appear to covary with male penile features. Our findings highlight the importance of considering interactions between the sexes in influencing functional reproductive structures and examine how these structures have been under selection in bats.

A new freshwater gastropod species of the genus Pseudamnicola Paulucci, 1878 from Algeria (Gastropoda: Hydrobiidae)

Pseudamnicola thawintae sp. n. (Gastropoda, Hydrobiidae) is described from Ait-Bouaddou, Tizi-Ouzou (Algeria) by the shells and the anatomy. In addition, photos of the shell and the penis morphology are given and photos of the type locality.

The description of a new species of Anarthrotarsus Šilhavý from Greece and a discussion about the genus (Arachnida: Opiliones: Trogulidae)

Anarthrotarsus trichasi sp. nov., a second species of the genus Anarthrotarsus Šilhavý, 1967 is described based on fresh material from the northeastern part of the island of Crete, Greece. The male holotype of the type species of the genus Anarthrotarsus was discovered on the island of Corfu, Ionian Islands, Greece, but no other conspecific specimens were found there ever since. This also holds true for the population from Crete, from where a female paratype was collected. Genital morphology of male specimens from both populations markedly differs, and that of the holotype from Corfu is even unique among Trogulidae. Though the tarsal formula (1-1-1-1 in the four walking legs) is identical in both populations, penis morphology, the main generic character of Anarthrotarsus, clearly separates them. A close relationship of A. trichasi sp. nov. with species of the genus Calathocratus Simon, 1879 is supposed but awaits molecular genetic affirmation.

Penile shape discriminates two cryptic species of Akodon Meyen, 1833 (Mammalia, Rodentia, Cricetidae) from eastern Brazil.

Glans penis morphology has been used as a powerful tool in mammal taxonomy to differentiate cryptic species. Neotropical rodent species Akodoncursor and A.montensis are cryptic, and interspecific hybrids are like their parental species. We investigated non-metric and metric phallic characters aiming to differentiate A.cursor from A.montensis. We also evaluated the parental species' influence of the phallic characters on hybrids. We analysed 96 male adults-56 A.cursor, 27 A.montensis, and 13 hybrids, subgrouping species by locality and hybrids by parental species (paternal vs maternal). We verified that A.cursor and A.montensis are distinguishable by penile-shape morphology: A.cursor has an elongated penile form with a flare in the distal portion and A.montensis has a barrel-shaped form. Also, dark spots in ventral view, if present in A.montensis, distinguish A.montensis from A.cursor. Although the non-metric characters differentiate the species, they do not distinguish the subgroups of A.cursor, A.montensis, and hybrids. The metric phallic characters indicated a significant difference between species and hybrids. These characters also differentiate the population groups of A.cursor. However, A.montensis subgroups and hybrids subgroups did not present a significant difference. This study shows the importance of penis morphology in the taxonomy of the cryptic rodent species A.cursor and A.montensis, representing a powerful tool to discriminate male specimens in mammal collections without karyotyping or sequencing, even though the specimens occurred in sympatric areas. Since most taxidermy protocols do not preserve the penis in mammal preparations, liquid preservation of some specimens or the removal of the penis before taxidermy for liquid preservation could be beneficial. We also recommend the organisation in museum collections of a penis bank for the A.cursor species group (or even all rodent species) to avoid losing this important information for species identification.

Description of a new valvatoid Pikasia smenensis n. gen. n. sp. (Gastropoda, Hydrobiidae) from Morocco

Recent field surveys conducted in the northern part of Morocco have led to the discovery of a new species belonging to a new genus Pikasia n. gen. described here. Photos of the holotype and paratype are presented in addition to the penis morphology and the female sex tract, the map of the sampling area with the type localities, and the habitat description

Comparative Morphology of the Male Genitalia of Japanese Muroidea Species

We examined the morphology of the male genitalia of six Muridae and five Cricetidae in the Muroidea focusing on the medial and lateral bacular mounds, as well as their ossification patterns to discuss the diversity and the movement mechanism of the trident structure. All examined species possessed a medial bacular mound and two lateral bacular mounds, which collectively formed a trident structure. In the Muridae species, the medial bacular mound was ossified or consisted of cartilage, while the lateral bacular mounds were composed of soft tissue. By contrast, both the medial and lateral bacular mounds were ossified in the Cricetidae species. Among the Muridae species, the medial bacular mound was well developed, and the lateral bacular mounds were small in Mus and Micromys species while the medial bacular mound was highly developed, and the lateral bacular mounds were developed in Apodemus speciosus. Different combinations of developmental characteristics of the medial and lateral bacular mounds produced variation in the glans penis morphology. Histological examination of A. speciosus and Craseomys rufocanus suggested that the movement of the lateral bacular mounds was driven by blood flowing into the cavernous space, and the movement increases the cross-sectional area of the glans penis.

Penis morphology of two European mole species (Soricomorpha, Talpidae)

The penis of the recently described mole Talpa martinorum and its relative, the European mole Talpa europaea, are described and compared. Considerable differences in the morphology of the glans penis were found: the apical part is narrow and rod-like in T. martinorum and conical in T. europaea; the keratinous papillae covering the basal part of the glans are shorter and in fewer groups in T. martinorum than in T. europaea. The os penis is nearly 30 % longer in T. martinorum than in the other species. The corpora cavernosa in both mole species are well developed and uniformly organized from the base of the penis to its apical region. The urethra is dorsoventrally flattened and widened in the apical part. Seasonal development of the keratinous papillae is observed in both species: they are found only during the breeding season. This phenomenon has never been reported before in any mammalian group.

3D genital shape complexity in female marine mammals.

Comparisons of 3D shapes have recently been applied to diverse anatomical structures using landmarking techniques. However, discerning evolutionary patterns can be challenging for structures lacking homologous landmarks. We used alpha shape analyses to quantify vaginal shape complexity in 40 marine mammal specimens including cetaceans, pinnipeds, and sirenians. We explored phylogenetic signal and the potential roles of natural and sexual selection on vaginal shape evolution. Complexity scores were consistent with qualitative observations. Cetaceans had a broad range of alpha complexities, while pinnipeds were comparatively simple and sirenians were complex. Intraspecific variation was found. Three‐dimensional surface heat maps revealed that shape complexity was driven by invaginations and protrusions of the vaginal wall. Phylogenetic signal was weak and metrics of natural selection (relative neonate size) and sexual selection (relative testes size, sexual size dimorphism, and penis morphology) did not explain vaginal complexity patterns. Additional metrics, such as penile shape complexity, may yield interesting insights into marine mammal genital coevolution. We advocate for the use of alpha shapes to discern patterns of evolution that would otherwise not be possible in 3D anatomical structures lacking homologous landmarks.

Two new species of the genera Islamia and Mercuria (Gastropoda, Hydrobiidae) from Morocco

Two new hydrobiid species Islamia karawiyiensis n. sp and Mercuria atlasica n. sp. are described here from Fez prefecture of Morocco. Samples were collected in 2020. Photos of the holotypes are presented in addition to the penis morphology of the new Mercuria. The map of the sampling area with the type locality and the habitat description are given.

Bythinella charpentieri (Roth, 1855), found again after 165 years (Mollusca: Gastropoda: Bythinellidae)

In this paper the finding of a living specimens of Bythinella charpentieri (Roth, 1855), including description of the penis morphology is given.

Geometric morphometrics of mandibular shape in the dwarf fat-tailed jerboa: relevancy for trinomial taxonomy

Abstract We explore the pattern of spatial variation in mandibular morphology in relation to subspecific taxonomy in the dwarf fat-tailed jerboa, Pygeretmus pumilio. The unguided k-means clustering on mandible shape scores, partitioned populations into two clusters, corresponding to western and eastern populations. These clusters nearly perfectly matched the two subspecies groups (pumilio and potanini groups) recognized in an independent study based on the morphology of the glans penis. The mandible, although under environmental pressure, has retained a sufficient amount of taxonomic information to retrieve grouping closely resembling the one derived from a sexually selective trait. We recommend morphometrics of the mandible as a routine step in addressing variations in mammals at species and subspecies levels. We also stress the advantage of unsupervised k-clustering in testing null expectation in subspecies taxonomies. However, the power of this approach has its limitations and in our analysis, the k-clustering failed to retrieve subspecies in the potanini group.

Penis morphology facilitates identification of cryptic African bat species

AbstractAfrica hosts a high number of bat species, many of which have been poorly studied. Among African vesper bats (Vespertilionidae), some species are morphologically similar to each other, hampering identification in the field. Consequently, basic information on these species’ population dynamics, distributions, or behaviors is vague and/or incorrectly documented. Among some Vespertilionidae, variation in flaccid penis shape enables species identification. This variation in morphology is thought to have resulted from sexual selection operating on the erect penis. Furthermore, in the context of strong postcopulatory competition, divergence in sperm traits may have evolved among closely related species. These male reproductive characters have hitherto not been investigated in southern African vespertilionid bats. In this study, we present the morphology of flaccid penis, erect penis, and sperm, of six small vesper species, based on the prediction that these characters have evolved sufficiently toward different optima to allow species discrimination. Species identification based solely on the morphological characters of the penis entirely matched species identification based on traditional (craniodental) characters. We illustrate penis morphology of these species to assist with field identifications for future ecological, conservation, or behavioral studies. Sperm morphology was sufficient to discriminate between the different genera, but could not reliably separate Neoromicia nana, Ne. zuluensis, and Ne. capensis. Hence, we demonstrate that these difficult to identify species can be readily distinguished based on traits directly observable in the field and on living animals, which will lead to more focused field studies on these otherwise morphologically cryptic species. Finally, our comparisons of penis morphology support the suggestion that Hypsugo anchietae is better placed within the genus Neoromicia.

Two new valvatoid genera (Gastropoda, Hydrobiidae) from Morocco

Recent field surveys conducted on the Middle Atlas of Morocco have led to the discovery of two new species belonging to two new genera (Ifrania n. gen. and Fessia n. gen.) described here. Photos of the holotypes are presented in addition to the penis morphology of the new genera, the map of the sampling area with the type localities and the habitat description. Ongoing investigations will possibly reveal more new genera and species from the country.

<span lang="IT">A new genus and two new species (Gastropoda, Hydrobiidae) from Morocco</span>

From 2014 to 2019 at more than 100 localities freshwater molluscs were collected along the basin of Moulouya River and Oriental Region of Morocco. These samples revealed two new hydrobiid species which are described here. One new species of Islamia and one species of a new genus. Photos of the holotypes are presented in addition to the penis morphology of the new genus and a map of the sampling area with the type localities.

Qorimayus, a new genus of relictual, high-altitude harvestmen from western Argentina (Arachnida, Opiliones, Gonyleptidae) reveals trans-Andean phylogenetic links.

A new genus of Gonyleptidae Pachylinae, Qorimayus gen. nov., is described to place the high-altitude species originally named Parabalta alticola Ringuelet, endemic to Sierra de Famatina, western Argentina. While classical exomorphological features do not separate this new genus from Parabalta Roewer or Pachyloides Holmberg (to which the species was formerly combined), male genitalic features, especially the shape of the ventral process of stylus, differ clearly. In turn, penis morphology suggests the systematic relationship of Qorimayus gen. nov. with the Chilean genera Metabalta Roewer and Nanophareus Roewer. A cladistic analysis was performed to test the phylogenetic affinities of the new genus; 28 terminals were used, comprising selected species of Parabalta, Pachyloides, Metabalta and Nanophareus, as well as other Gonyleptidae to represent the 'subtropical' and the 'Chilean' opiliofaunistic elements; the most external outgroups included one cosmetid, one metasarcid and one nomoclastid. Results supported the recognition of Qorimayus as an independent genus, and its close relationship with the Chilean genera Metabalta and Nanophareus. A detailed redescription of Qorimayus alticola comb. nov., along with some habitat notes are given. The presumed zoogeographical links of this endemic species with the central Chilean opiliofauna are briefly discussed.